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3.1 快速⼊⻔

<properties>

<project.build.sourceEncoding>

UTF-8

</project.build.sourceEncoding>

<maven.compiler.encoding>

UTF-8

</maven.compiler.encoding>

<java.version>

1.8

</java.version>

<maven.compiler.source>

1.8

</maven.compiler.source>

<maven.compiler.target>

1.8

</maven.compiler.target>

</properties>

<!--mybatis

坐标

-->

<dependency>

<groupId>

org.mybatis

</groupId>

<artifactId>

mybatis

</artifactId>

<version>

3.4.5

</version>

</dependency>

<!--mysql

驱动坐标

-->

<dependency>

<groupId>

mysql

</groupId>

<artifactId>

mysql-connector-java

</artifactId>

<version>

5.1.6

</version>

<scope>

runtime

</scope>

</dependency>

<!--

单元测试坐标

-->

<dependency>

<groupId>

junit

</groupId>

<artifactId>

junit

</artifactId>

<version>

4.12

</version>

<scope>

test

</scope>

</dependency>

<!--

⽇志坐标

-->

<dependency>

<groupId>

log4j

</groupId>

<artifactId>

log4j

</artifactId>

<version>

1.2.12

</version>

</dependency>

 创建数据库表，使用原来zdy_mybatis的user表

package com.ch.pojo;public class User {    private Integer id;    private String username;    public Integer getId() {        return id;    }    public void setId(Integer id) {        this.id = id;    }    public String getUsername() {        return username;    }    public void setUsername(String username) {        this.username = username;    }    @Override    public String toString() {        return "User{" +                "id=" + id +                ", username='" + username + '\'' +                '}';    }}

4）编写UserMapper映射⽂件

     
         
          
             select * from user    
     

5) 编写MyBatis核⼼⽂件

 6） 编写测试代码

package com.ch.test;import com.ch.pojo.User;import org.apache.ibatis.io.Resources;import org.apache.ibatis.session.SqlSession;import org.apache.ibatis.session.SqlSessionFactory;import org.apache.ibatis.session.SqlSessionFactoryBuilder;import org.junit.Test;import java.io.IOException;import java.io.InputStream;import java.util.List;public class MybatisTest {    @Test    public void test() throws IOException {        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);        SqlSession sqlSession = sqlSessionFactory.openSession();        List
    
      userList = sqlSession.selectList("user.findAll");        for (User user:userList) {            System.out.println("用户数据"+user);        }    }}
    

运行结果

用户数据User{id=1, username='zhangsan'}

用户数据User{id=2, username='lisi'}

     
          insert into user values(#{id},#{username})
     

@Testpublic void testInsert() throws IOException {    InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");    SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);    SqlSession sqlSession = sqlSessionFactory.openSession();    User user = new User();    user.setId(4);    user.setUsername("test");     sqlSession.insert("user.saveUser",user);     //增删改的时候必须提交事务     sqlSession.commit();          sqlSession.close();}

执行成功

 测试结果

测试结果

 

//Resource:工具类，配置文件的加载，把配置文件加载成字节输入流InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");//解析配置文件，创建了sqlSessionFactory工厂SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);//生产了sqlSessionSqlSession sqlSession = sqlSessionFactory.openSession();//默认开启了一个事务，但是不会自动提交                                                       //在增删改时要手动提交事务,传入参数为true的时候会自动提交事务//4.sqlSession调用方法：查询所有调用selectList，查询单个调用selectOne，添加：insert 修改调用update，删除调用deleteList
     
       userList = sqlSession.selectList("user.findAll");
     

 

<

T

>

T

selectOne

(

String

statement

,

Object

parameter

)

<

E

>

List

<

E

>

selectList

(

String

statement

,

Object

parameter

)

int

insert

(

String

statement

,

Object

parameter

)

int

update

(

String

statement

,

Object

parameter

)

int

delete

(

String

statement

,

Object

parameter

)

操作事务的⽅法主要有：

void

commit

()

void

rollback

()

public interface IUserDao {    //查询所有用户    public List
     
       findAll();}
     

package com.ch.dao;import com.ch.pojo.User;import org.apache.ibatis.io.Resources;import org.apache.ibatis.session.SqlSession;import org.apache.ibatis.session.SqlSessionFactory;import org.apache.ibatis.session.SqlSessionFactoryBuilder;import java.io.IOException;import java.io.InputStream;import java.util.List;public class UserDaoImpl implements IUserDao{    @Override    public List
     
       findAll() throws IOException {        //Resource:工具类，配置文件的加载，把配置文件加载成字节输入流        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");        //解析配置文件，创建了sqlSessionFactory工厂        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);        //生产了sqlSession        SqlSession sqlSession = sqlSessionFactory.openSession();//默认开启了一个事务，但是不会自动提交        //在增删改时要手动提交事务,传入参数为true的时候会自动提交事务        //4.sqlSession调用方法：查询所有调用selectList，查询单个调用selectOne，添加：insert 修改调用update，删除调用delete        List
      
        userList = sqlSession.selectList("user.findAll");        for (User user:userList) {            System.out.println("用户数据"+user);        }        return userList;    }}
      
     

测试传统方式

@Testpublic void test5() throws IOException {    IUserDao userDao=new UserDaoImpl();    List
    
      all = userDao.findAll();    System.out.println("查询全部数据"+all);}
    

测试结果锅

查询全部数据[User{id=2, username='修改'}, User{id=4, username='test'}]

@Testpublic void test5() throws IOException {    InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");    SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);    SqlSession sqlSession = sqlSessionFactory.openSession();    IUserDao userDao=sqlSession.getMapper(IUserDao.class);    List
     
       all = userDao.findAll();    System.out.println("用户信息"+all);    sqlSession.close();}