第十节第八部分：Lambda表达式、Lambda表达式的省略规则

Lambda表达式介绍

Lambda表达式Comparator接口的匿名形式

Lambda表达式简化setAll方法中匿名内部类

进一步简化Lambda表达式

代码

代码一：认识Lambda表达式

package com.itheima.Lambda;public class LambdaTest1 {public static void main(String[] args) {//目标：认识Lambda表达式Animal a = new Animal() {@Overridepublic void run() {System.out.println("狗跑得贼快~~~");}};a.run();//注意:Lambda表达式并不是说能简化全部名内部类的写法，只能简化函数式接口的匿名内部类。//错误的代码!
//        Animal b = ()->{
//            System.out.println("狗跑得贼快~~~");
//        };
//        b.run();Swimming s1 = new Swimming() {@Overridepublic void swim() {System.out.println("学生游泳~~~");}};s1.swim();Swimming s2 =()->{System.out.println("学生游泳~~~");};s2.swim();}
}abstract class Animal{public abstract void run();
}interface Swimming{void swim();
}```![结果1](https://i-blog.csdnimg.cn/direct/53a1d1ddc8234885ae93226c1faf1031.png#pic_center)
## 代码二：使用Lambda简化函数式接口。```java
package com.itheima.Lambda;import com.itheima.Arrays.Student;import java.util.Arrays;
import java.util.Comparator;
import java.util.function.IntToDoubleFunction;public class LambdaTest2 {public static void main(String[] args) {// 目标:使用Lambda简化函数式接口。//案例一double[] prices = {100,300,200};//                  0   1   2//把所有的价格都打八折，然后又存进去。
//        Arrays.setAll(prices, new IntToDoubleFunction() {
//            @Override
//            public double applyAsDouble(int value) {
//                //value = 0  1  2
//                return prices[value] * 0.8;
//            }
//        });
//        Arrays.setAll(prices,(int value)->{ return prices[value] * 0.8;});//Arrays.setAll(prices,(value)->{ return prices[value] * 0.8;});//        Arrays.setAll(prices,value->{ return prices[value] * 0.8;});Arrays.setAll(prices,value-> prices[value] * 0.8);System.out.println(Arrays.toString(prices));//案例二Student[] students = new Student[3];students[0] = new Student("飞鸟马时",18,165);students[1] = new Student("枣伊吕波",17,155);students[2] = new Student("珈百璃",19,150);//        Arrays.sort(students, new Comparator<Student>() {
//            @Override
//            public int compare(Student o1, Student o2) {
//                return Double.compare(o2.getHeight(), o1.getHeight());//降序
//            }
//        });//        Arrays.sort(students, (Student o1, Student o2)-> {
//                return Double.compare(o2.getHeight(), o1.getHeight());//降序
//            }
//        );//        Arrays.sort(students, ( o1,  o2)-> {
//                    return Double.compare(o2.getHeight(), o1.getHeight());//降序
//                }
//        );Arrays.sort(students, ( o1,  o2)->Double.compare(o2.getHeight(), o1.getHeight()));System.out.println(Arrays.toString(students));}
}