不带，以及带参数，带返回值的Lambda表达式

无参数无返回值

package com.wcy;
//lambda推导必须存在类型
public class Lambda {
    //静态内部类
    static class Like2 implements ILike{
        @Override
        public void lambda() {
            System.out.println("I like lambda2");
        }
    }
    public static void main(String[] args) {
        ILike like = new Like();
        like.lambda();
        like = new Like2();
        like.lambda();
        //局部内部类
        class Like3 implements ILike{
            public void lambda() {
                System.out.println("I like lambda3");
            }
        }
        like = new Like3();
        like.lambda();
        //匿名内部类
        like = new ILike() {
            public void lambda() {
                System.out.println("I like lambda4");
            }    
        };
        like.lambda();
        //lambda
        like = ()->{
            System.out.println("I like lambda5");
        };
        like.lambda();
    }
}

interface ILike{
    void lambda();
}
//外部类
class Like implements ILike{
    @Override
    public void lambda() {
        System.out.println("I like lambda1");
    }
}

带参数

package com.wcy;
public class Lambda2{
    public static void main(String[] args) {
        ILove love=(int a)->{    //可以省略int，自定跟接口匹配。只有一个参数的时候（）也可以省略，如果只有一行代码，{ }也可以省略！
            System.out.println("i love lambda  "+a);
        };
        love.lambda(100);
        
        love=(a)->{    //省略int 自定跟接口匹配
            System.out.println("i love lambda  "+a);
        };
        love.lambda(99);

        love=a->{    //只有一个参数的时候 ()也可以省略
            System.out.println("i love lambda  "+a);
        };
        love.lambda(98);
    }
}
interface ILove{
    void lambda(int a);
}

带参数的带返回值的

package com.wcy;
public class Lambda3 {
    public static void main(String[] args) {
        ILove love=(int a,int b)->{  
            System.out.println("i love lambda  "+(a+b));
            return a+b;
        };
        System.out.println(love.lambda(100,200));
    } 
}
interface ILove{
    int lambda(int a,int b);
}

带参数的带返回值的

package com.wcy;
public class Lambda3 {
    public static void main(String[] args) {
        ILove love=(int a,int b)->{  
            System.out.println("i love lambda  "+(a+b));
            return a+b;
        };
        love.lambda(12, 16);
        
        love=(a,b)->{  
            System.out.println("i love lambda  "+(a+b));
            return a+b;
        };
        love.lambda(12, 10);
        
        love=(a,b)->{ 
            return a+b;
        };
        System.out.println(love.lambda(12, 8));
        
        love=(a,b)->a+b;
        System.out.println(love.lambda(12, 6));
    } 
}
interface ILove{
    int lambda(int a,int b);
}