day23 lambda表达式

lambda推导

定义函数式接口

1 interface ILike{
2      void lambda();
3  }

实现类

1  class Like implements ILike{
2  
3      @Override
4      public void lambda() {
5          System.out.println("I like lambda");
6      }
7  }

静态内部类

1 static class Like2 implements ILike{
2  
3      @Override
4      public void lambda() {
5          System.out.println("I like lambda2");
6      }
7  }

局部内部类

1  class Like3 implements ILike{
2  
3      @Override
4      public void lambda() {
5          System.out.println("I like lambda3");
6      }
7  }

匿名内部类

1 like = new ILike() {
2      @Override
3      public void lambda() {
4          System.out.println("I like lambda4");
5      }
6  };

lambda表达式简化

1  like = () ->{
2      System.out.println("I like lambda5");
3  };

主函数：

 1  public static void main(String[] args) {
 2      ILike like = new Like();
 3      like.lambda();
 4      like = new Like2();
 5      like.lambda();
 6      //4. 局部内部类
 7      class Like3 implements ILike{
 8  
 9          @Override
10          public void lambda() {
11              System.out.println("I like lambda3");
12          }
13      }
14      like = new Like3();
15      like.lambda();
16      //5. 匿名内部类 没有类的名称，必须借助接口或者父类
17      like = new ILike() {
18          @Override
19          public void lambda() {
20              System.out.println("I like lambda4");
21          }
22      };
23      like.lambda();
24      //6. 用lambda表达式简化
25      like = () ->{
26          System.out.println("I like lambda5");
27      };
28      like.lambda();
29  
30  }