java流式计算Stream (重点)

简单例子

下面我们给出一段代码

public class Test {
    public static void main(String[] args) {
        User u1 =new User(1,"a",21);
        User u2 =new User(2,"b",22);
        User u3 =new User(3,"c",23);
        User u4 =new User(4,"d",24);
        User u5 =new User(6,"e",25);
        //集合就是存储
        List<User> list = Arrays.asList(u1, u2, u3, u4, u5);
        //计算交给Stream
    }
}

给你一个题目

而实现方法就要靠我们NB的Stream流了！

package com.jie.stream;

import java.lang.reflect.Array;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;

public class Test {
    public static void main(String[] args) {
        User u1 =new User(1,"a",21);
        User u2 =new User(2,"b",22);
        User u3 =new User(3,"c",23);
        User u4 =new User(4,"d",24);
        User u5 =new User(6,"e",25);
        //集合就是存储
        List<User> list = Arrays.asList(u1, u2, u3, u4, u5);
        //计算交给Stream
        //链式编程
        list.stream()
                .filter(u-> u.getId()%2==0)
                .filter(u-> u.getAge()>23)
                .map(u-> u.getName().toUpperCase())
                .sorted(Comparator.reverseOrder())
                .limit(1)
                .forEach(System.out::println);
    }
}

具体API说明

https://www.jianshu.com/p/354e2db0a06e