Java从入门到实战之（28）Java 目录操作之练习
发布日期：2021-05-14 00:18:26
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分类：博客文章
本文共 82236 字，大约阅读时间需要 274 分钟。
1、递归创建目录
使用 File 类的 mkdirs() 实现递归创建目录？
import java.io.File; public class Main { public static void main(String[] args) { String directories = "D:\\a\\b\\c\\d\\e\\f\\g\\h\\i"; File file = new File(directories); boolean result = file.mkdirs(); System.out.println("Status = " + result); }} 结果：
Status = true
2、删除目录
使用 File 类的 ofdir.isDirectory(), dir.list() 和 deleteDir() 方法在一个个删除文件后删除目录？
import java.io.File; public class Main { public static void main(String[] argv) throws Exception { // 删除当前目录下的 test 目录 deleteDir(new File("./test")); } public static boolean deleteDir(File dir) { if (dir.isDirectory()) { String[] children = dir.list(); for (int i = 0; i < children.length; i++) { boolean success = deleteDir (new File(dir, children[i])); if (!success) { return false; } } } if(dir.delete()) { System.out.println("目录已被删除！"); return true; } else { System.out.println("目录删除失败！"); return false; } }} 结果：
目录已被删除！
3、判断目录是否为空
使用 File 类的 file.isDirectory() 和 file.list() 方法来判断目录是否为空？
import java.io.File; public class Main{ public static void main(String[] args) { File file = new File("./testdir"); // 当前目录下的 testdir目录 if(file.isDirectory()){ if(file.list().length>0){ System.out.println("目录不为空!"); }else{ System.out.println("目录为空!"); } }else{ System.out.println("这不是一个目录!"); } }} 结果：
目录 D://Java/file.txt 不为空！
4、判断文件是否隐藏
使用 File 类的 file.isHidden() 方法来判断文件是否隐藏？
import java.io.File; public class Main { public static void main(String[] args) { File file = new File("C:/Demo.txt"); System.out.println(file.isHidden()); }} 结果：
True
5、获取目录大小
使用 File 类的 FileUtils.sizeofDirectory(File Name) 来获取目录的大小？
package Practice;import org.apache.commons.io.FileUtils;import java.io.File;/** * @program: FlinkUdf * @description: 文件目录 * @author: BigData * @create: 2020-11-09 14:19 **/public class Test1 { public static void main(String[] args) { String directories = "C:\\文档\\个人学习资料\\IOTest\\"; dirSize(directories); } /** * @Description: 目录文件的大小 * @Param: [dir] * @return: void * @Author: BigData * @Date: 2020/11/9 */ public static void dirSize(String dir) { File file=new File(dir); long size= FileUtils.sizeOfDirectory(file); System.out.println(dir+"的目录大小是："+size+"bytes"); }} 结果：
"C:\Program Files\Java\jdk1.8.0_221\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\lib\idea_rt.jar=50891:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_221\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\resources.jar;C:\Program 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Practice.Test1C:\文档\个人学习资料\IOTest\的目录大小是：79bytesProcess finished with exit code 0
6、在指定目录中查找文件
使用 File 类的 dir.list() 方法在指定目录中查找所有文件列表？
package Practice;import org.apache.commons.io.FileUtils;import java.io.File;/** * @program: FlinkUdf * @description: 文件目录 * @author: BigData * @create: 2020-11-09 14:19 **/public class Test1 { public static void main(String[] args) { String directories = "C:\\文档\\个人学习资料\\IOTest\\"; dirFindFile(directories); } /** * @Description: 在指定目录中查找文件 * @Param: [dir] * @return: void * @Author: BigData * @Date: 2020/11/9 */ private static void dirFindFile(String dir) { File file=new File(dir); String[] s=file.list(); if(s==null) { System.out.println("目录不存在"); } else { for(String x:s) { System.out.println("文件名:"+x); } } }} 结果：
"C:\Program Files\Java\jdk1.8.0_221\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\lib\idea_rt.jar=51845:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_221\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\resources.jar;C:\Program 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Practice.Test1文件名:01.txt文件名:a文件名:HelloWorld.txt文件名:rainbow1.txt文件名:rainbow2.txt文件名:rainbowTest.txtProcess finished with exit code 0
import java.io.*; class Main { public static void main(String[] args) { File dir = new File("C:"); FilenameFilter filter = new FilenameFilter() { public boolean accept (File dir, String name) { return name.startsWith("b"); } }; String[] children = dir.list(filter); if (children == null) { System.out.println("目录不存在或它不是一个目录"); } else { for (int i=0; i < children.length; i++) { String filename = children[i]; System.out.println(filename); } } }} 结果：
buildbuild.xml
7、获取文件的上级目录
使用 File 类的 file.getParent() 方法来获取文件的上级目录？
package Practice;import org.apache.commons.io.FileUtils;import java.io.File;/** * @program: FlinkUdf * @description: 文件目录 * @author: BigData * @create: 2020-11-09 14:19 **/public class Test1 { public static void main(String[] args) { String directories = "C:\\文档\\个人学习资料\\IOTest\\"; getParentDir(directories); } /** * @Description: 获取文件父级目录 * @Param: [dir] * @return: void * @Author: BigData * @Date: 2020/11/9 */ private static void getParentDir(String dir) { File file=new File(dir); System.out.println("文件上级目录是:"+file.getParent()); }} 结果：
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Files\Java\jdk1.8.0_221\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\resources.jar;C:\Program 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ltuser0\.m2\repository\org\scala-lang\scala-reflect\2.11.12\scala-reflect-2.11.12.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\scala-library\2.11.12\scala-library-2.11.12.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\scala-compiler\2.11.12\scala-compiler-2.11.12.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\modules\scala-xml_2.11\1.0.5\scala-xml_2.11-1.0.5.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\modules\scala-parser-combinators_2.11\1.0.4\scala-parser-combinators_2.11-1.0.4.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-common\1.11.1\flink-table-common-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-core\1.11.1\flink-core-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-annotations\1.11.1\flink-annotations-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-metrics-core\1.11.1\flink-metrics-core-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\com\esotericsoftware\kryo\kryo\2.24.0\kryo-2.24.0.jar;C:\Users\defaultuser0\.m2\repository\com\esotericsoftware\minlog\minlog\1.2\minlog-1.2.jar;C:\Users\defaultuser0\.m2\repository\org\objenesis\objenesis\2.1\objenesis-2.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\commons\commons-compress\1.20\commons-compress-1.20.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-asm-7\7.1-11.0\flink-shaded-asm-7-7.1-11.0.jar;C:\Users\defaultuser0\.m2\repository\com\alibaba\fastjson\1.2.73\fastjson-1.2.73.jar;C:\Users\defaultuser0\.m2\repository\org\slf4j\slf4j-log4j12\1.7.7\slf4j-log4j12-1.7.7.jar;C:\Users\defaultuser0\.m2\repository\log4j\log4j\1.2.17\log4j-1.2.17.jar;C:\Users\defaultuser0\.m2\repository\net\sf\json-lib\json-lib\2.4\json-lib-2.4-jdk15.jar;C:\Users\defaultuser0\.m2\repository\commons-beanutils\commons-beanutils\1.8.0\commons-beanutils-1.8.0.jar;C:\Users\defaultuser0\.m2\repository\commons-collections\commons-collections\3.2.1\commons-collections-3.2.1.jar;C:\Users\defaultuser0\.m2\repository\commons-lang\commons-lang\2.5\commons-lang-2.5.jar;C:\Users\defaultuser0\.m2\repository\commons-logging\commons-logging\1.1.1\commons-logging-1.1.1.jar;C:\Users\defaultuser0\.m2\repository\net\sf\ezmorph\ezmorph\1.0.6\ezmorph-1.0.6.jar;C:\Users\defaultuser0\.m2\repository\org\json\json\20180813\json-20180813.jar" Practice.Test1文件上级目录是:C:\文档\个人学习资料Process finished with exit code 0
8、获取目录最后修改时间
使用 File 类的 file.lastModified() 方法来获取目录的最后修改时间?
package Practice;import org.apache.commons.io.FileUtils;import java.io.File;import java.util.Date;/** * @program: FlinkUdf * @description: 文件目录 * @author: BigData * @create: 2020-11-09 14:19 **/public class Test1 { public static void main(String[] args) { String directories = "C:\\文档\\个人学习资料\\IOTest\\"; getLastModify(directories); } /** * @Description: 获取目录最后修改时间 * @Param: [dir] * @return: void * @Author: BigData * @Date: 2020/11/9 */ private static void getLastModify(String dir) { File file=new File(dir); System.out.println(dir+"的最后修改时间是："+new Date(file.lastModified())); }} 结果：
"C:\Program Files\Java\jdk1.8.0_221\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\lib\idea_rt.jar=52675:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_221\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\rt.jar;C:\app\FlinkUdf\target\test-classes;C:\Users\defaultuser0\.m2\repository\junit\junit\4.11\junit-4.11.jar;C:\Users\defaultuser0\.m2\repository\org\hamcrest\hamcrest-core\1.3\hamcrest-core-1.3.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-api-java-bridge_2.11\1.11.1\flink-table-api-java-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-api-java\1.11.1\flink-table-api-java-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-java\1.11.1\flink-java-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\commons\commons-lang3\3.3.2\commons-lang3-3.3.2.jar;C:\Users\defaultuser0\.m2\repository\org\apache\commons\commons-math3\3.5\commons-math3-3.5.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-runtime_2.11\1.11.1\flink-runtime_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-queryable-state-client-java\1.11.1\flink-queryable-state-client-java-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-hadoop-fs\1.11.1\flink-hadoop-fs-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\commons-io\commons-io\2.4\commons-io-2.4.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-netty\4.1.39.Final-11.0\flink-shaded-netty-4.1.39.Final-11.0.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-jackson\2.10.1-11.0\flink-shaded-jackson-2.10.1-11.0.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-zookeeper-3\3.4.14-11.0\flink-shaded-zookeeper-3-3.4.14-11.0.jar;C:\Users\defaultuser0\.m2\repository\commons-cli\commons-cli\1.3.1\commons-cli-1.3.1.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\akka\akka-actor_2.11\2.5.21\akka-actor_2.11-2.5.21.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\config\1.3.3\config-1.3.3.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\modules\scala-java8-compat_2.11\0.7.0\scala-java8-compat_2.11-0.7.0.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\akka\akka-stream_2.11\2.5.21\akka-stream_2.11-2.5.21.jar;C:\Users\defaultuser0\.m2\repository\org\reactivestreams\reactive-streams\1.0.2\reactive-streams-1.0.2.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\ssl-config-core_2.11\0.3.7\ssl-config-core_2.11-0.3.7.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\akka\akka-protobuf_2.11\2.5.21\akka-protobuf_2.11-2.5.21.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\akka\akka-slf4j_2.11\2.5.21\akka-slf4j_2.11-2.5.21.jar;C:\Users\defaultuser0\.m2\repository\org\clapper\grizzled-slf4j_2.11\1.3.2\grizzled-slf4j_2.11-1.3.2.jar;C:\Users\defaultuser0\.m2\repository\com\github\scopt\scopt_2.11\3.5.0\scopt_2.11-3.5.0.jar;C:\Users\defaultuser0\.m2\repository\org\xerial\snappy\snappy-java\1.1.4\snappy-java-1.1.4.jar;C:\Users\defaultuser0\.m2\repository\com\twitter\chill_2.11\0.7.6\chill_2.11-0.7.6.jar;C:\Users\defaultuser0\.m2\repository\com\twitter\chill-java\0.7.6\chill-java-0.7.6.jar;C:\Users\defaultuser0\.m2\repository\org\lz4\lz4-java\1.6.0\lz4-java-1.6.0.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-guava\18.0-11.0\flink-shaded-guava-18.0-11.0.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1-tests.jar;C:\Users\defaultuser0\.m2\repository\org\slf4j\slf4j-api\1.7.15\slf4j-api-1.7.15.jar;C:\Users\defaultuser0\.m2\repository\com\google\code\findbugs\jsr305\1.3.9\jsr305-1.3.9.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\force-shading\1.11.1\force-shading-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-planner-blink_2.11\1.11.1\flink-table-planner-blink_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-api-scala_2.11\1.11.1\flink-table-api-scala_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-api-scala-bridge_2.11\1.11.1\flink-table-api-scala-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-runtime-blink_2.11\1.11.1\flink-table-runtime-blink_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\codehaus\janino\janino\3.0.9\janino-3.0.9.jar;C:\Users\defaultuser0\.m2\repository\org\codehaus\janino\commons-compiler\3.0.9\commons-compiler-3.0.9.jar;C:\Users\defaultuser0\.m2\repository\org\apache\calcite\avatica\avatica-core\1.16.0\avatica-core-1.16.0.jar;C:\Users\defaultuser0\.m2\repository\org\reflections\reflections\0.9.10\reflections-0.9.10.jar;C:\Users\defaultuser0\.m2\repository\org\javassist\javassist\3.19.0-GA\javassist-3.19.0-GA.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-streaming-scala_2.11\1.11.1\flink-streaming-scala_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-scala_2.11\1.11.1\flink-scala_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\scala-reflect\2.11.12\scala-reflect-2.11.12.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\scala-library\2.11.12\scala-library-2.11.12.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\scala-compiler\2.11.12\scala-compiler-2.11.12.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\modules\scala-xml_2.11\1.0.5\scala-xml_2.11-1.0.5.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\modules\scala-parser-combinators_2.11\1.0.4\scala-parser-combinators_2.11-1.0.4.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-common\1.11.1\flink-table-common-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-core\1.11.1\flink-core-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-annotations\1.11.1\flink-annotations-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-metrics-core\1.11.1\flink-metrics-core-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\com\esotericsoftware\kryo\kryo\2.24.0\kryo-2.24.0.jar;C:\Users\defaultuser0\.m2\repository\com\esotericsoftware\minlog\minlog\1.2\minlog-1.2.jar;C:\Users\defaultuser0\.m2\repository\org\objenesis\objenesis\2.1\objenesis-2.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\commons\commons-compress\1.20\commons-compress-1.20.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-asm-7\7.1-11.0\flink-shaded-asm-7-7.1-11.0.jar;C:\Users\defaultuser0\.m2\repository\com\alibaba\fastjson\1.2.73\fastjson-1.2.73.jar;C:\Users\defaultuser0\.m2\repository\org\slf4j\slf4j-log4j12\1.7.7\slf4j-log4j12-1.7.7.jar;C:\Users\defaultuser0\.m2\repository\log4j\log4j\1.2.17\log4j-1.2.17.jar;C:\Users\defaultuser0\.m2\repository\net\sf\json-lib\json-lib\2.4\json-lib-2.4-jdk15.jar;C:\Users\defaultuser0\.m2\repository\commons-beanutils\commons-beanutils\1.8.0\commons-beanutils-1.8.0.jar;C:\Users\defaultuser0\.m2\repository\commons-collections\commons-collections\3.2.1\commons-collections-3.2.1.jar;C:\Users\defaultuser0\.m2\repository\commons-lang\commons-lang\2.5\commons-lang-2.5.jar;C:\Users\defaultuser0\.m2\repository\commons-logging\commons-logging\1.1.1\commons-logging-1.1.1.jar;C:\Users\defaultuser0\.m2\repository\net\sf\ezmorph\ezmorph\1.0.6\ezmorph-1.0.6.jar;C:\Users\defaultuser0\.m2\repository\org\json\json\20180813\json-20180813.jar" Practice.Test1C:\文档\个人学习资料\IOTest\的最后修改时间是：Mon Nov 09 14:27:33 CST 2020Process finished with exit code 0
9、打印目录结构
使用 File 类的 file.getName() 和 file.listFiles() 方法来打印目录结构？
package Practice;import org.apache.commons.io.FileUtils;import java.io.File;import java.io.IOException;import java.util.Date;/** * @program: FlinkUdf * @description: 文件目录 * @author: BigData * @create: 2020-11-09 14:19 **/public class Test1 { public static void main(String[] args) { String directories = "C:\\文档\\个人学习资料\\IOTest\\"; showDir(1,new File(directories)); } /** * @Description: 打印目录结构 * @Param: [indent, file] * @return: void * @Author: BigData * @Date: 2020/11/9 */ private static void showDir(int indent, File file) { for (int i = 0; i < indent; i++) System.out.print('-'); System.out.println(file.getName()); if (file.isDirectory()) { File[] files = file.listFiles(); for (int i = 0; i < files.length; i++) showDir(indent + 4, files[i]); } }} 结果：
"C:\Program Files\Java\jdk1.8.0_221\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\lib\idea_rt.jar=52901:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_221\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\rt.jar;C:\app\FlinkUdf\target\test-classes;C:\Users\defaultuser0\.m2\repository\junit\junit\4.11\junit-4.11.jar;C:\Users\defaultuser0\.m2\repository\org\hamcrest\hamcrest-core\1.3\hamcrest-core-1.3.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-api-java-bridge_2.11\1.11.1\flink-table-api-java-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-api-java\1.11.1\flink-table-api-java-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-java\1.11.1\flink-java-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\commons\commons-lang3\3.3.2\commons-lang3-3.3.2.jar;C:\Users\defaultuser0\.m2\repository\org\apache\commons\commons-math3\3.5\commons-math3-3.5.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-runtime_2.11\1.11.1\flink-runtime_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-queryable-state-client-java\1.11.1\flink-queryable-state-client-java-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-hadoop-fs\1.11.1\flink-hadoop-fs-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\commons-io\commons-io\2.4\commons-io-2.4.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-netty\4.1.39.Final-11.0\flink-shaded-netty-4.1.39.Final-11.0.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-jackson\2.10.1-11.0\flink-shaded-jackson-2.10.1-11.0.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-zookeeper-3\3.4.14-11.0\flink-shaded-zookeeper-3-3.4.14-11.0.jar;C:\Users\defaultuser0\.m2\repository\commons-cli\commons-cli\1.3.1\commons-cli-1.3.1.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\akka\akka-actor_2.11\2.5.21\akka-actor_2.11-2.5.21.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\config\1.3.3\config-1.3.3.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\modules\scala-java8-compat_2.11\0.7.0\scala-java8-compat_2.11-0.7.0.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\akka\akka-stream_2.11\2.5.21\akka-stream_2.11-2.5.21.jar;C:\Users\defaultuser0\.m2\repository\org\reactivestreams\reactive-streams\1.0.2\reactive-streams-1.0.2.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\ssl-config-core_2.11\0.3.7\ssl-config-core_2.11-0.3.7.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\akka\akka-protobuf_2.11\2.5.21\akka-protobuf_2.11-2.5.21.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\akka\akka-slf4j_2.11\2.5.21\akka-slf4j_2.11-2.5.21.jar;C:\Users\defaultuser0\.m2\repository\org\clapper\grizzled-slf4j_2.11\1.3.2\grizzled-slf4j_2.11-1.3.2.jar;C:\Users\defaultuser0\.m2\repository\com\github\scopt\scopt_2.11\3.5.0\scopt_2.11-3.5.0.jar;C:\Users\defaultuser0\.m2\repository\org\xerial\snappy\snappy-java\1.1.4\snappy-java-1.1.4.jar;C:\Users\defaultuser0\.m2\repository\com\twitter\chill_2.11\0.7.6\chill_2.11-0.7.6.jar;C:\Users\defaultuser0\.m2\repository\com\twitter\chill-java\0.7.6\chill-java-0.7.6.jar;C:\Users\defaultuser0\.m2\repository\org\lz4\lz4-java\1.6.0\lz4-java-1.6.0.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-guava\18.0-11.0\flink-shaded-guava-18.0-11.0.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1-tests.jar;C:\Users\defaultuser0\.m2\repository\org\slf4j\slf4j-api\1.7.15\slf4j-api-1.7.15.jar;C:\Users\defaultuser0\.m2\repository\com\google\code\findbugs\jsr305\1.3.9\jsr305-1.3.9.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\force-shading\1.11.1\force-shading-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-planner-blink_2.11\1.11.1\flink-table-planner-blink_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-api-scala_2.11\1.11.1\flink-table-api-scala_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-api-scala-bridge_2.11\1.11.1\flink-table-api-scala-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-runtime-blink_2.11\1.11.1\flink-table-runtime-blink_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\codehaus\janino\janino\3.0.9\janino-3.0.9.jar;C:\Users\defaultuser0\.m2\repository\org\codehaus\janino\commons-compiler\3.0.9\commons-compiler-3.0.9.jar;C:\Users\defaultuser0\.m2\repository\org\apache\calcite\avatica\avatica-core\1.16.0\avatica-core-1.16.0.jar;C:\Users\defaultuser0\.m2\repository\org\reflections\reflections\0.9.10\reflections-0.9.10.jar;C:\Users\defaultuser0\.m2\repository\org\javassist\javassist\3.19.0-GA\javassist-3.19.0-GA.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-streaming-scala_2.11\1.11.1\flink-streaming-scala_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-scala_2.11\1.11.1\flink-scala_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\scala-reflect\2.11.12\scala-reflect-2.11.12.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\scala-library\2.11.12\scala-library-2.11.12.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\scala-compiler\2.11.12\scala-compiler-2.11.12.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\modules\scala-xml_2.11\1.0.5\scala-xml_2.11-1.0.5.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\modules\scala-parser-combinators_2.11\1.0.4\scala-parser-combinators_2.11-1.0.4.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-common\1.11.1\flink-table-common-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-core\1.11.1\flink-core-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-annotations\1.11.1\flink-annotations-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-metrics-core\1.11.1\flink-metrics-core-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\com\esotericsoftware\kryo\kryo\2.24.0\kryo-2.24.0.jar;C:\Users\defaultuser0\.m2\repository\com\esotericsoftware\minlog\minlog\1.2\minlog-1.2.jar;C:\Users\defaultuser0\.m2\repository\org\objenesis\objenesis\2.1\objenesis-2.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\commons\commons-compress\1.20\commons-compress-1.20.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-asm-7\7.1-11.0\flink-shaded-asm-7-7.1-11.0.jar;C:\Users\defaultuser0\.m2\repository\com\alibaba\fastjson\1.2.73\fastjson-1.2.73.jar;C:\Users\defaultuser0\.m2\repository\org\slf4j\slf4j-log4j12\1.7.7\slf4j-log4j12-1.7.7.jar;C:\Users\defaultuser0\.m2\repository\log4j\log4j\1.2.17\log4j-1.2.17.jar;C:\Users\defaultuser0\.m2\repository\net\sf\json-lib\json-lib\2.4\json-lib-2.4-jdk15.jar;C:\Users\defaultuser0\.m2\repository\commons-beanutils\commons-beanutils\1.8.0\commons-beanutils-1.8.0.jar;C:\Users\defaultuser0\.m2\repository\commons-collections\commons-collections\3.2.1\commons-collections-3.2.1.jar;C:\Users\defaultuser0\.m2\repository\commons-lang\commons-lang\2.5\commons-lang-2.5.jar;C:\Users\defaultuser0\.m2\repository\commons-logging\commons-logging\1.1.1\commons-logging-1.1.1.jar;C:\Users\defaultuser0\.m2\repository\net\sf\ezmorph\ezmorph\1.0.6\ezmorph-1.0.6.jar;C:\Users\defaultuser0\.m2\repository\org\json\json\20180813\json-20180813.jar" Practice.Test1-IOTest-----01.txt-----a---------b-------------c-----------------d---------------------e-------------------------f-----------------------------g---------------------------------h-----HelloWorld.txt-----rainbow1.txt-----rainbow2.txt-----rainbowTest.txtProcess finished with exit code 0
10、遍历指定目录下的所有目录
如何使用 File 类的 list 方法来遍历指定目录下的所有目录？
package Practice;import org.apache.commons.io.FileUtils;import java.io.File;import java.io.FileFilter;import java.io.IOException;import java.util.Date;/** * @program: FlinkUdf * @description: 文件目录 * @author: BigData * @create: 2020-11-09 14:19 **/public class Test1 { public static void main(String[] args) { String directories = "C:\\文档\\个人学习资料\\IOTest\\"; ergodicDir(directories); } /** * @Description: 遍历指定目录下的所有目录 * @Param: [dir] * @return: void * @Author: BigData * @Date: 2020/11/9 */ private static void ergodicDir(String dir) { File file=new File(dir); File[] files=file.listFiles(); FileFilter fileFilter=new FileFilter() { @Override public boolean accept(File file1) { return file1.isDirectory(); } }; files=file.listFiles(fileFilter);// System.out.println(files.length); if(files.length==0) { System.out.println("目录不存在或它不是一个目录"); } else { for(File x:files) { System.out.println(x.toString()); } } }} 结果：
"C:\Program Files\Java\jdk1.8.0_221\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\lib\idea_rt.jar=53058:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_221\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\rt.jar;C:\app\FlinkUdf\target\test-classes;C:\Users\defaultuser0\.m2\repository\junit\junit\4.11\junit-4.11.jar;C:\Users\defaultuser0\.m2\repository\org\hamcrest\hamcrest-core\1.3\hamcrest-core-1.3.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-api-java-bridge_2.11\1.11.1\flink-table-api-java-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-api-java\1.11.1\flink-table-api-java-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-java\1.11.1\flink-java-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\commons\commons-lang3\3.3.2\commons-lang3-3.3.2.jar;C:\Users\defaultuser0\.m2\repository\org\apache\commons\commons-math3\3.5\commons-math3-3.5.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-runtime_2.11\1.11.1\flink-runtime_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-queryable-state-client-java\1.11.1\flink-queryable-state-client-java-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-hadoop-fs\1.11.1\flink-hadoop-fs-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\commons-io\commons-io\2.4\commons-io-2.4.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-netty\4.1.39.Final-11.0\flink-shaded-netty-4.1.39.Final-11.0.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-jackson\2.10.1-11.0\flink-shaded-jackson-2.10.1-11.0.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-zookeeper-3\3.4.14-11.0\flink-shaded-zookeeper-3-3.4.14-11.0.jar;C:\Users\defaultuser0\.m2\repository\commons-cli\commons-cli\1.3.1\commons-cli-1.3.1.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\akka\akka-actor_2.11\2.5.21\akka-actor_2.11-2.5.21.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\config\1.3.3\config-1.3.3.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\modules\scala-java8-compat_2.11\0.7.0\scala-java8-compat_2.11-0.7.0.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\akka\akka-stream_2.11\2.5.21\akka-stream_2.11-2.5.21.jar;C:\Users\defaultuser0\.m2\repository\org\reactivestreams\reactive-streams\1.0.2\reactive-streams-1.0.2.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\ssl-config-core_2.11\0.3.7\ssl-config-core_2.11-0.3.7.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\akka\akka-protobuf_2.11\2.5.21\akka-protobuf_2.11-2.5.21.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\akka\akka-slf4j_2.11\2.5.21\akka-slf4j_2.11-2.5.21.jar;C:\Users\defaultuser0\.m2\repository\org\clapper\grizzled-slf4j_2.11\1.3.2\grizzled-slf4j_2.11-1.3.2.jar;C:\Users\defaultuser0\.m2\repository\com\github\scopt\scopt_2.11\3.5.0\scopt_2.11-3.5.0.jar;C:\Users\defaultuser0\.m2\repository\org\xerial\snappy\snappy-java\1.1.4\snappy-java-1.1.4.jar;C:\Users\defaultuser0\.m2\repository\com\twitter\chill_2.11\0.7.6\chill_2.11-0.7.6.jar;C:\Users\defaultuser0\.m2\repository\com\twitter\chill-java\0.7.6\chill-java-0.7.6.jar;C:\Users\defaultuser0\.m2\repository\org\lz4\lz4-java\1.6.0\lz4-java-1.6.0.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-guava\18.0-11.0\flink-shaded-guava-18.0-11.0.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1-tests.jar;C:\Users\defaultuser0\.m2\repository\org\slf4j\slf4j-api\1.7.15\slf4j-api-1.7.15.jar;C:\Users\defaultuser0\.m2\repository\com\google\code\findbugs\jsr305\1.3.9\jsr305-1.3.9.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\force-shading\1.11.1\force-shading-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-planner-blink_2.11\1.11.1\flink-table-planner-blink_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-api-scala_2.11\1.11.1\flink-table-api-scala_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-api-scala-bridge_2.11\1.11.1\flink-table-api-scala-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-runtime-blink_2.11\1.11.1\flink-table-runtime-blink_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\codehaus\janino\janino\3.0.9\janino-3.0.9.jar;C:\Users\defaultuser0\.m2\repository\org\codehaus\janino\commons-compiler\3.0.9\commons-compiler-3.0.9.jar;C:\Users\defaultuser0\.m2\repository\org\apache\calcite\avatica\avatica-core\1.16.0\avatica-core-1.16.0.jar;C:\Users\defaultuser0\.m2\repository\org\reflections\reflections\0.9.10\reflections-0.9.10.jar;C:\Users\defaultuser0\.m2\repository\org\javassist\javassist\3.19.0-GA\javassist-3.19.0-GA.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-streaming-scala_2.11\1.11.1\flink-streaming-scala_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-scala_2.11\1.11.1\flink-scala_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\scala-reflect\2.11.12\scala-reflect-2.11.12.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\scala-library\2.11.12\scala-library-2.11.12.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\scala-compiler\2.11.12\scala-compiler-2.11.12.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\modules\scala-xml_2.11\1.0.5\scala-xml_2.11-1.0.5.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\modules\scala-parser-combinators_2.11\1.0.4\scala-parser-combinators_2.11-1.0.4.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-common\1.11.1\flink-table-common-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-core\1.11.1\flink-core-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-annotations\1.11.1\flink-annotations-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-metrics-core\1.11.1\flink-metrics-core-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\com\esotericsoftware\kryo\kryo\2.24.0\kryo-2.24.0.jar;C:\Users\defaultuser0\.m2\repository\com\esotericsoftware\minlog\minlog\1.2\minlog-1.2.jar;C:\Users\defaultuser0\.m2\repository\org\objenesis\objenesis\2.1\objenesis-2.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\commons\commons-compress\1.20\commons-compress-1.20.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-asm-7\7.1-11.0\flink-shaded-asm-7-7.1-11.0.jar;C:\Users\defaultuser0\.m2\repository\com\alibaba\fastjson\1.2.73\fastjson-1.2.73.jar;C:\Users\defaultuser0\.m2\repository\org\slf4j\slf4j-log4j12\1.7.7\slf4j-log4j12-1.7.7.jar;C:\Users\defaultuser0\.m2\repository\log4j\log4j\1.2.17\log4j-1.2.17.jar;C:\Users\defaultuser0\.m2\repository\net\sf\json-lib\json-lib\2.4\json-lib-2.4-jdk15.jar;C:\Users\defaultuser0\.m2\repository\commons-beanutils\commons-beanutils\1.8.0\commons-beanutils-1.8.0.jar;C:\Users\defaultuser0\.m2\repository\commons-collections\commons-collections\3.2.1\commons-collections-3.2.1.jar;C:\Users\defaultuser0\.m2\repository\commons-lang\commons-lang\2.5\commons-lang-2.5.jar;C:\Users\defaultuser0\.m2\repository\commons-logging\commons-logging\1.1.1\commons-logging-1.1.1.jar;C:\Users\defaultuser0\.m2\repository\net\sf\ezmorph\ezmorph\1.0.6\ezmorph-1.0.6.jar;C:\Users\defaultuser0\.m2\repository\org\json\json\20180813\json-20180813.jar" Practice.Test1C:\文档\个人学习资料\IOTest\aProcess finished with exit code 0
11、输出指定目录下的所有文件
如何使用 File 类的 list 方法来输出指定目录下的所有文件？
package Practice;import org.apache.commons.io.FileUtils;import java.io.File;import java.io.FileFilter;import java.io.IOException;import java.util.Date;/** * @program: FlinkUdf * @description: 文件目录 * @author: BigData * @create: 2020-11-09 14:19 **/public class Test1 { public static void main(String[] args) { String directories = "C:\\文档\\个人学习资料\\IOTest\\"; ergodicFile(directories); } /** * @Description: 遍历指定目录下的所有文件 * @Param: [dir] * @return: void * @Author: BigData * @Date: 2020/11/9 */ private static void ergodicFile(String dir) { File file = new File(dir); String list[]=file.list(); if(list==null) { System.out.println("目录不存在或它不是一个目录"); } else { for (String x:list) { System.out.println(x); } } }} 结果：
"C:\Program Files\Java\jdk1.8.0_221\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\lib\idea_rt.jar=53139:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_221\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\rt.jar;C:\app\FlinkUdf\target\test-classes;C:\Users\defaultuser0\.m2\repository\junit\junit\4.11\junit-4.11.jar;C:\Users\defaultuser0\.m2\repository\org\hamcrest\hamcrest-core\1.3\hamcrest-core-1.3.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-api-java-bridge_2.11\1.11.1\flink-table-api-java-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-api-java\1.11.1\flink-table-api-java-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-java\1.11.1\flink-java-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\commons\commons-lang3\3.3.2\commons-lang3-3.3.2.jar;C:\Users\defaultuser0\.m2\repository\org\apache\commons\commons-math3\3.5\commons-math3-3.5.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-runtime_2.11\1.11.1\flink-runtime_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-queryable-state-client-java\1.11.1\flink-queryable-state-client-java-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-hadoop-fs\1.11.1\flink-hadoop-fs-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\commons-io\commons-io\2.4\commons-io-2.4.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-netty\4.1.39.Final-11.0\flink-shaded-netty-4.1.39.Final-11.0.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-jackson\2.10.1-11.0\flink-shaded-jackson-2.10.1-11.0.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-zookeeper-3\3.4.14-11.0\flink-shaded-zookeeper-3-3.4.14-11.0.jar;C:\Users\defaultuser0\.m2\repository\commons-cli\commons-cli\1.3.1\commons-cli-1.3.1.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\akka\akka-actor_2.11\2.5.21\akka-actor_2.11-2.5.21.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\config\1.3.3\config-1.3.3.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\modules\scala-java8-compat_2.11\0.7.0\scala-java8-compat_2.11-0.7.0.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\akka\akka-stream_2.11\2.5.21\akka-stream_2.11-2.5.21.jar;C:\Users\defaultuser0\.m2\repository\org\reactivestreams\reactive-streams\1.0.2\reactive-streams-1.0.2.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\ssl-config-core_2.11\0.3.7\ssl-config-core_2.11-0.3.7.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\akka\akka-protobuf_2.11\2.5.21\akka-protobuf_2.11-2.5.21.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\akka\akka-slf4j_2.11\2.5.21\akka-slf4j_2.11-2.5.21.jar;C:\Users\defaultuser0\.m2\repository\org\clapper\grizzled-slf4j_2.11\1.3.2\grizzled-slf4j_2.11-1.3.2.jar;C:\Users\defaultuser0\.m2\repository\com\github\scopt\scopt_2.11\3.5.0\scopt_2.11-3.5.0.jar;C:\Users\defaultuser0\.m2\repository\org\xerial\snappy\snappy-java\1.1.4\snappy-java-1.1.4.jar;C:\Users\defaultuser0\.m2\repository\com\twitter\chill_2.11\0.7.6\chill_2.11-0.7.6.jar;C:\Users\defaultuser0\.m2\repository\com\twitter\chill-java\0.7.6\chill-java-0.7.6.jar;C:\Users\defaultuser0\.m2\repository\org\lz4\lz4-java\1.6.0\lz4-java-1.6.0.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-guava\18.0-11.0\flink-shaded-guava-18.0-11.0.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1-tests.jar;C:\Users\defaultuser0\.m2\repository\org\slf4j\slf4j-api\1.7.15\slf4j-api-1.7.15.jar;C:\Users\defaultuser0\.m2\repository\com\google\code\findbugs\jsr305\1.3.9\jsr305-1.3.9.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\force-shading\1.11.1\force-shading-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-planner-blink_2.11\1.11.1\flink-table-planner-blink_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-api-scala_2.11\1.11.1\flink-table-api-scala_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-api-scala-bridge_2.11\1.11.1\flink-table-api-scala-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-runtime-blink_2.11\1.11.1\flink-table-runtime-blink_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\codehaus\janino\janino\3.0.9\janino-3.0.9.jar;C:\Users\defaultuser0\.m2\repository\org\codehaus\janino\commons-compiler\3.0.9\commons-compiler-3.0.9.jar;C:\Users\defaultuser0\.m2\repository\org\apache\calcite\avatica\avatica-core\1.16.0\avatica-core-1.16.0.jar;C:\Users\defaultuser0\.m2\repository\org\reflections\reflections\0.9.10\reflections-0.9.10.jar;C:\Users\defaultuser0\.m2\repository\org\javassist\javassist\3.19.0-GA\javassist-3.19.0-GA.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-streaming-scala_2.11\1.11.1\flink-streaming-scala_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-scala_2.11\1.11.1\flink-scala_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\scala-reflect\2.11.12\scala-reflect-2.11.12.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\scala-library\2.11.12\scala-library-2.11.12.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\scala-compiler\2.11.12\scala-compiler-2.11.12.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\modules\scala-xml_2.11\1.0.5\scala-xml_2.11-1.0.5.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\modules\scala-parser-combinators_2.11\1.0.4\scala-parser-combinators_2.11-1.0.4.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-common\1.11.1\flink-table-common-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-core\1.11.1\flink-core-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-annotations\1.11.1\flink-annotations-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-metrics-core\1.11.1\flink-metrics-core-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\com\esotericsoftware\kryo\kryo\2.24.0\kryo-2.24.0.jar;C:\Users\defaultuser0\.m2\repository\com\esotericsoftware\minlog\minlog\1.2\minlog-1.2.jar;C:\Users\defaultuser0\.m2\repository\org\objenesis\objenesis\2.1\objenesis-2.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\commons\commons-compress\1.20\commons-compress-1.20.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-asm-7\7.1-11.0\flink-shaded-asm-7-7.1-11.0.jar;C:\Users\defaultuser0\.m2\repository\com\alibaba\fastjson\1.2.73\fastjson-1.2.73.jar;C:\Users\defaultuser0\.m2\repository\org\slf4j\slf4j-log4j12\1.7.7\slf4j-log4j12-1.7.7.jar;C:\Users\defaultuser0\.m2\repository\log4j\log4j\1.2.17\log4j-1.2.17.jar;C:\Users\defaultuser0\.m2\repository\net\sf\json-lib\json-lib\2.4\json-lib-2.4-jdk15.jar;C:\Users\defaultuser0\.m2\repository\commons-beanutils\commons-beanutils\1.8.0\commons-beanutils-1.8.0.jar;C:\Users\defaultuser0\.m2\repository\commons-collections\commons-collections\3.2.1\commons-collections-3.2.1.jar;C:\Users\defaultuser0\.m2\repository\commons-lang\commons-lang\2.5\commons-lang-2.5.jar;C:\Users\defaultuser0\.m2\repository\commons-logging\commons-logging\1.1.1\commons-logging-1.1.1.jar;C:\Users\defaultuser0\.m2\repository\net\sf\ezmorph\ezmorph\1.0.6\ezmorph-1.0.6.jar;C:\Users\defaultuser0\.m2\repository\org\json\json\20180813\json-20180813.jar" Practice.Test101.txtaHelloWorld.txtrainbow1.txtrainbow2.txtrainbowTest.txtProcess finished with exit code 0
12、查看系统根目录
使用 File 类的 listRoots() 方法来输出系统所有根目录？
package Practice;import org.apache.commons.io.FileUtils;import java.io.File;import java.io.FileFilter;import java.io.IOException;import java.util.Date;/** * @program: FlinkUdf * @description: 文件目录 * @author: BigData * @create: 2020-11-09 14:19 **/public class Test1 { public static void main(String[] args) { String directories = "C:\\文档\\个人学习资料\\IOTest\\"; ergodicRootDir(); } /** * @Description: 遍历根目录 * @Param: [dir] * @return: void * @Author: BigData * @Date: 2020/11/9 */ private static void ergodicRootDir() { //技巧：Ctrl+Alt+V快速生成变量名 File[] roots = File.listRoots(); System.out.println("系统所有根目录："); for (File s:roots) { System.out.println(s.toString()); } }} 结果：
"C:\Program Files\Java\jdk1.8.0_221\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\lib\idea_rt.jar=53342:C:\Program Files\JetBrains\IntelliJ IDEA 2019.3.3\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_221\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_221\jre\lib\rt.jar;C:\app\FlinkUdf\target\test-classes;C:\Users\defaultuser0\.m2\repository\junit\junit\4.11\junit-4.11.jar;C:\Users\defaultuser0\.m2\repository\org\hamcrest\hamcrest-core\1.3\hamcrest-core-1.3.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-api-java-bridge_2.11\1.11.1\flink-table-api-java-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-api-java\1.11.1\flink-table-api-java-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-java\1.11.1\flink-java-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\commons\commons-lang3\3.3.2\commons-lang3-3.3.2.jar;C:\Users\defaultuser0\.m2\repository\org\apache\commons\commons-math3\3.5\commons-math3-3.5.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-runtime_2.11\1.11.1\flink-runtime_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-queryable-state-client-java\1.11.1\flink-queryable-state-client-java-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-hadoop-fs\1.11.1\flink-hadoop-fs-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\commons-io\commons-io\2.4\commons-io-2.4.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-netty\4.1.39.Final-11.0\flink-shaded-netty-4.1.39.Final-11.0.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-jackson\2.10.1-11.0\flink-shaded-jackson-2.10.1-11.0.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-zookeeper-3\3.4.14-11.0\flink-shaded-zookeeper-3-3.4.14-11.0.jar;C:\Users\defaultuser0\.m2\repository\commons-cli\commons-cli\1.3.1\commons-cli-1.3.1.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\akka\akka-actor_2.11\2.5.21\akka-actor_2.11-2.5.21.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\config\1.3.3\config-1.3.3.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\modules\scala-java8-compat_2.11\0.7.0\scala-java8-compat_2.11-0.7.0.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\akka\akka-stream_2.11\2.5.21\akka-stream_2.11-2.5.21.jar;C:\Users\defaultuser0\.m2\repository\org\reactivestreams\reactive-streams\1.0.2\reactive-streams-1.0.2.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\ssl-config-core_2.11\0.3.7\ssl-config-core_2.11-0.3.7.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\akka\akka-protobuf_2.11\2.5.21\akka-protobuf_2.11-2.5.21.jar;C:\Users\defaultuser0\.m2\repository\com\typesafe\akka\akka-slf4j_2.11\2.5.21\akka-slf4j_2.11-2.5.21.jar;C:\Users\defaultuser0\.m2\repository\org\clapper\grizzled-slf4j_2.11\1.3.2\grizzled-slf4j_2.11-1.3.2.jar;C:\Users\defaultuser0\.m2\repository\com\github\scopt\scopt_2.11\3.5.0\scopt_2.11-3.5.0.jar;C:\Users\defaultuser0\.m2\repository\org\xerial\snappy\snappy-java\1.1.4\snappy-java-1.1.4.jar;C:\Users\defaultuser0\.m2\repository\com\twitter\chill_2.11\0.7.6\chill_2.11-0.7.6.jar;C:\Users\defaultuser0\.m2\repository\com\twitter\chill-java\0.7.6\chill-java-0.7.6.jar;C:\Users\defaultuser0\.m2\repository\org\lz4\lz4-java\1.6.0\lz4-java-1.6.0.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-guava\18.0-11.0\flink-shaded-guava-18.0-11.0.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-streaming-java_2.11\1.11.1\flink-streaming-java_2.11-1.11.1-tests.jar;C:\Users\defaultuser0\.m2\repository\org\slf4j\slf4j-api\1.7.15\slf4j-api-1.7.15.jar;C:\Users\defaultuser0\.m2\repository\com\google\code\findbugs\jsr305\1.3.9\jsr305-1.3.9.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\force-shading\1.11.1\force-shading-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-planner-blink_2.11\1.11.1\flink-table-planner-blink_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-api-scala_2.11\1.11.1\flink-table-api-scala_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-api-scala-bridge_2.11\1.11.1\flink-table-api-scala-bridge_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-runtime-blink_2.11\1.11.1\flink-table-runtime-blink_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\codehaus\janino\janino\3.0.9\janino-3.0.9.jar;C:\Users\defaultuser0\.m2\repository\org\codehaus\janino\commons-compiler\3.0.9\commons-compiler-3.0.9.jar;C:\Users\defaultuser0\.m2\repository\org\apache\calcite\avatica\avatica-core\1.16.0\avatica-core-1.16.0.jar;C:\Users\defaultuser0\.m2\repository\org\reflections\reflections\0.9.10\reflections-0.9.10.jar;C:\Users\defaultuser0\.m2\repository\org\javassist\javassist\3.19.0-GA\javassist-3.19.0-GA.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-streaming-scala_2.11\1.11.1\flink-streaming-scala_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-scala_2.11\1.11.1\flink-scala_2.11-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\scala-reflect\2.11.12\scala-reflect-2.11.12.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\scala-library\2.11.12\scala-library-2.11.12.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\scala-compiler\2.11.12\scala-compiler-2.11.12.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\modules\scala-xml_2.11\1.0.5\scala-xml_2.11-1.0.5.jar;C:\Users\defaultuser0\.m2\repository\org\scala-lang\modules\scala-parser-combinators_2.11\1.0.4\scala-parser-combinators_2.11-1.0.4.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-table-common\1.11.1\flink-table-common-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-core\1.11.1\flink-core-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-annotations\1.11.1\flink-annotations-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-metrics-core\1.11.1\flink-metrics-core-1.11.1.jar;C:\Users\defaultuser0\.m2\repository\com\esotericsoftware\kryo\kryo\2.24.0\kryo-2.24.0.jar;C:\Users\defaultuser0\.m2\repository\com\esotericsoftware\minlog\minlog\1.2\minlog-1.2.jar;C:\Users\defaultuser0\.m2\repository\org\objenesis\objenesis\2.1\objenesis-2.1.jar;C:\Users\defaultuser0\.m2\repository\org\apache\commons\commons-compress\1.20\commons-compress-1.20.jar;C:\Users\defaultuser0\.m2\repository\org\apache\flink\flink-shaded-asm-7\7.1-11.0\flink-shaded-asm-7-7.1-11.0.jar;C:\Users\defaultuser0\.m2\repository\com\alibaba\fastjson\1.2.73\fastjson-1.2.73.jar;C:\Users\defaultuser0\.m2\repository\org\slf4j\slf4j-log4j12\1.7.7\slf4j-log4j12-1.7.7.jar;C:\Users\defaultuser0\.m2\repository\log4j\log4j\1.2.17\log4j-1.2.17.jar;C:\Users\defaultuser0\.m2\repository\net\sf\json-lib\json-lib\2.4\json-lib-2.4-jdk15.jar;C:\Users\defaultuser0\.m2\repository\commons-beanutils\commons-beanutils\1.8.0\commons-beanutils-1.8.0.jar;C:\Users\defaultuser0\.m2\repository\commons-collections\commons-collections\3.2.1\commons-collections-3.2.1.jar;C:\Users\defaultuser0\.m2\repository\commons-lang\commons-lang\2.5\commons-lang-2.5.jar;C:\Users\defaultuser0\.m2\repository\commons-logging\commons-logging\1.1.1\commons-logging-1.1.1.jar;C:\Users\defaultuser0\.m2\repository\net\sf\ezmorph\ezmorph\1.0.6\ezmorph-1.0.6.jar;C:\Users\defaultuser0\.m2\repository\org\json\json\20180813\json-20180813.jar" Practice.Test1系统所有根目录：C:\Process finished with exit code 0
13、查看当前工作目录
使用 System 的 getProperty() 方法来获取当前的工作目录？
class Main { public static void main(String[] args) { String curDir = System.getProperty("user.dir"); System.out.println("你当前的工作目录为 :" + curDir); }} 结果：
你当前的工作目录为 :/www/java
14、遍历目录
使用 File 类的 dir.isDirectory() 和 dir.list() 方法来遍历目录？
import java.io.File; public class Main { public static void main(String[] argv) throws Exception { System.out.println("遍历目录"); File dir = new File("/www/java"); //要遍历的目录 visitAllDirsAndFiles(dir); } public static void visitAllDirsAndFiles(File dir) { System.out.println(dir); if (dir.isDirectory()) { String[] children = dir.list(); for (int i = 0; i < children.length; i++) { visitAllDirsAndFiles(new File(dir, children[i])); } } }} 结果：
遍历目录/www/java/www/java/Car.class/www/java/FileUtil.class/www/java/FileUtil.java/www/java/HelloWorld.class/www/java/HelloWorld.java/www/java/HelloWorldDebug.class/www/java/HelloWorldDebug.java/www/java/Main$1.class/www/java/Main.class/www/java/Main.java/www/java/MainClass.class/www/java/MainClass.java/www/java/MyClass.class/www/java/outfilename/www/java/test.log
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