Lambda常用写法

Posted 2021-02-21 xiaofengfree

1、排序

import lombok.Data;
import java.util.*;
import java.util.stream.Collectors;

public class StreamStudy {

    public static void main(String[] args) {
        User u1 = new User("陈一",32);
        User u2 = new User("陈二",23);
        User u3 = new User("陈三",33);
        List<User> users = new ArrayList<>();
        users.add(u1);
        users.add(u2);
        users.add(u3);
        List<User> collect1 = users.stream().sorted(Comparator.comparing(User::getAge)).collect(Collectors.toList());
        System.out.println(collect1);
        List<User> collect2 = users.stream().sorted(Comparator.comparing(User::getAge).reversed()).collect(Collectors.toList());
        System.out.println(collect2);
    }
}

@Data
class User {
    public User() {}
    public User(String name, int age) {
        this.name = name;
        this.age = age;
    }
    String name;
    int age;
}