Lambda语法格式

package com.zwq;

import org.junit.Test;

import java.util.Comparator;
import java.util.function.Consumer;

/**
 * @author zhangwq
 *
 * Lambda语法格式
 * 1、无参数，无返回值 ()->System.out.println("hello world!");
 * 2、有一个参数无返回值  (x)->System.out.println(x);
 * 3、有一个参数，小括号可以不写
 * 4、有两个及以上参数，有返回值，lambda体有多条语句，需要{}需要return
 * 5、lambda体只有一条语句，return和{}可以省略
 * 6、lambda表达式数据类型可以省略，“类型推断”
 * 7、函数式接口支持，只有一个抽象方法
 */
public class LambdaLearn {
    @Test
    public void test(){
        //1
        Runnable runnable = ()-> System.out.println("hello");
        runnable.run();
        //2
        Consumer<Integer> con = (x)-> System.out.println("接收到值："+x);
        con.accept(1);
        //3
        Consumer<Integer> consumer = x-> System.out.println("接收到值："+x);
        consumer.accept(2);
        //4
        Comparator<Integer> comparator = (Integer x,Integer y)->{
            System.out.println("多条语句");
            return Integer.compare(x,y);
        };
        System.out.println(comparator.compare(1,2));
        //5
        Comparator<Integer> com = (Integer x,Integer y)-> Integer.compare(x,y);
        System.out.println(com.compare(2,1));
        //6
        Comparator<Integer> comNoType = (x,y)-> Integer.compare(x,y);
        System.out.println(comNoType.compare(2,2));
        //7
        String wlfsb = oprator("man",(x) ->  "I am a "+x);
        System.out.println(wlfsb);
    }

    public String oprator(String str,MyFunction myFunction){
        return myFunction.doMyOperation(str);
    }

}