Java 8 Lambda 表达式

绿林寻猫
2021-12-08 / 0 评论 / 125 阅读 / 正在检测是否收录...

 

package com.example.demo;

public class Java8Tester {
    public static void main(String args[]){
        Java8Tester tester = new Java8Tester();

        // 类型声明
        MathOperation addition = (int a, int b) -> a + b;

        // 不用类型声明
        MathOperation subtraction = (a, b) -> a - b;

        // 大括号中的返回语句
        MathOperation multiplication = (int a, int b) -> { return a * b; };

        // 没有大括号及返回语句
        MathOperation division = (int a, int b) -> a / b;

        System.out.println("10 + 5 = " + tester.operate(10, 5, addition));
        System.out.println("10 - 5 = " + tester.operate(10, 5, subtraction));
        System.out.println("10 x 5 = " + tester.operate(10, 5, multiplication));
        System.out.println("10 / 5 = " + tester.operate(10, 5, division));

        // 不用括号
        GreetingService greetService1 = message ->
                System.out.println("Hello " + message);

        // 用括号
        GreetingService greetService2 = (message) ->
                System.out.println("Hello " + message);

        greetService1.sayMessage("Runoob");
        greetService2.sayMessage("Google");
    }

    interface MathOperation {
        int operation(int a, int b);
    }

    interface GreetingService {
        void sayMessage(String message);
    }

    private int operate(int a, int b, MathOperation mathOperation){
        return mathOperation.operation(a, b);
    }
}

输出结果:

 

 

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