局部内部类的特点与使用

特点

1. 不能用public private static 修饰类
2. 访问方法内的变量必须是finnal类型
3. 在方法体内返回实例
4. 外部类必然无法实例局部类

使用

import lombok.extern.java.Log;
import lombok.extern.slf4j.Slf4j;
@Slf4j
public class LocalInnerClassTest {
    private String outpara1="out param 1";
    private static String outpara2="out param 2";
    
    interface Inner{
        void print();
    }

    public Inner testLocalClass(){
        final String localInput="localInput";
       class LocalClass implements Inner{
                private String innerpara1="out param 1";
                
                private final   String innerpara2="out param 2";

            @Override
            public void print() {
              log.info("begin print"); 
              log.info("print {}",localInput);
              log.info("out param1 :{}",outpara1); 
            }

        }
        return new LocalClass();
    }
    public static Inner testLocalClass2(){
        class LocalClass implements Inner{
                 private  String innerpara1="iner param 1";
                 
                 private   String innerpara2="iner param 2";
 
             @Override
             public void print() {
               log.info("begin print"); 
               log.info("inner param1 :{}",innerpara1); 
               log.info("inner param2  :{}",innerpara2); 
             }
 
         }
         return new LocalClass();
     }
    public static void main(String[] args) {
        LocalInnerClassTest test=new LocalInnerClassTest();
        test.testLocalClass().print();
        testLocalClass2().print();
    }
}