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导入期工具类

import org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider;import org.springframework.context.annotation.ComponentScan;import org.springframework.context.annotation.ImportSelector;import org.springframework.core.io.support.PropertiesLoaderUtils;import org.springframework.core.type.AnnotationMetadata;import org.springframework.core.type.filter.AspectJTypeFilter;import org.springframework.core.type.filter.TypeFilter;import java.io.IOException;import java.util.HashSet;import java.util.Map;import java.util.Properties;import java.util.Set;public class CustomerImportSelector implements ImportSelector {
       private String expression;    public CustomerImportSelector(){
           try {
               //初始化时指定加载的properties文件名,就是你文件名            Properties loadAllProperties = PropertiesLoaderUtils.loadAllProperties("******.properties");            //设定加载的属性名，就是类似Myclass=com.lzb.dao.UserDao,com.lzb.dao.PersonDao            //****就对应key的值(Myclass)            expression = loadAllProperties.getProperty("****");        } catch (IOException e) {
               // TODO Auto-generated catch block            e.printStackTrace();        }    }    @Override    public String[] selectImports(AnnotationMetadata importingClassMetadata) {
           //1.定义扫描包的名称        String[] basePackages = null;        //2.判断有@Import注解的类上是否有@ComponentScan注解        if (importingClassMetadata.hasAnnotation(ComponentScan.class.getName())) {
               //3.取出@ComponentScan注解的属性            Map<String, Object> annotationAttributes = importingClassMetadata.getAnnotationAttributes(ComponentScan.class.getName());            //4.取出属性名称为basePackages属性的值            basePackages = (String[]) annotationAttributes.get("basePackages");        }        //5.判断是否有此属性（如果没有ComponentScan注解则属性值为null，如果有ComponentScan注解，则basePackages默认为空数组）        if (basePackages == null || basePackages.length == 0) {
               String basePackage = null;            try {
                   //6.取出包含@Import注解类的包名                basePackage = Class.forName(importingClassMetadata.getClassName()).getPackage().getName();            } catch (ClassNotFoundException e) {
                   e.printStackTrace();            }            //7.存入数组中            basePackages = new String[] {
   basePackage};        }        //8.创建类路径扫描器        ClassPathScanningCandidateComponentProvider scanner = new ClassPathScanningCandidateComponentProvider(false);        //9.创建类型过滤器(此处使用切入点表达式类型过滤器)        TypeFilter typeFilter = new AspectJTypeFilter(expression,this.getClass().getClassLoader());        //10.给扫描器加入类型过滤器        scanner.addIncludeFilter(typeFilter);        //11.创建存放全限定类名的集合        Set<String> classes = new HashSet<>();        //12.填充集合数据        for (String basePackage : basePackages) {
               scanner.findCandidateComponents(basePackage).forEach(beanDefinition -> classes.add(beanDefinition.getBeanClassName()));        }        //13.按照规则返回        return classes.toArray(new String[classes.size()]);    }}