day23 lambda表达式

lambda推导

1. 定义函数式接口

interface ILike{
     void lambda();
 }

 

2. 实现类

 class Like implements ILike{
 ​
     @Override
     public void lambda() {
         System.out.println("I like lambda");
     }
 }

 

3. 静态内部类

static class Like2 implements ILike{
 ​
     @Override
     public void lambda() {
         System.out.println("I like lambda2");
     }
 }

 

4. 局部内部类

 class Like3 implements ILike{
 ​
     @Override
     public void lambda() {
         System.out.println("I like lambda3");
     }
 }

 

5. 匿名内部类

like = new ILike() {
     @Override
     public void lambda() {
         System.out.println("I like lambda4");
     }
 };

 

6. lambda表达式简化

 like = () ->{
     System.out.println("I like lambda5");
 };

 

主函数：

 public static void main(String[] args) {
     ILike like = new Like();
     like.lambda();
     like = new Like2();
     like.lambda();
     //4. 局部内部类
     class Like3 implements ILike{
 ​
         @Override
         public void lambda() {
             System.out.println("I like lambda3");
         }
     }
     like = new Like3();
     like.lambda();
     //5. 匿名内部类 没有类的名称，必须借助接口或者父类
     like = new ILike() {
         @Override
         public void lambda() {
             System.out.println("I like lambda4");
         }
     };
     like.lambda();
     //6. 用lambda表达式简化
     like = () ->{
         System.out.println("I like lambda5");
     };
     like.lambda();
 ​
 }