实现Comparable接口和重写compareTo方法

当对象实现了Comparable接口重写了compareTo方法

如下：

public class User implements Comparable<User>{
    private int age;

    private String name;
    
    public User() {

    }

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

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }


    @Override
    public int compareTo(User o) {
        //年龄从小到大
        if(this.getAge() - o.getAge() > 0){
            return 1;
        }else if(this.getAge() - o.getAge() == 0){
            return this.getName().compareTo(o.getName());
        }

        return -1;
    }
}

测试：

        @Test
        public void userTestTwo(){
            User u1 = new User(12,"b");
            User u2 = new User(22,"y");
            User u3 = new User(22,"a");

            User[] users = {u1,u2,u3};

            System.out.println("排序前:");

            for (User user:users) {
                System.out.println(user.toString());
            }

            System.out.println();

            //进行排序
            Arrays.sort(users);

            System.out.println("排序后：");
            for (User user:users) {
                System.out.println(user.toString());
            }

        }

控制台打印结果：

排序前:
User{age=12, name='b'}
User{age=22, name='y'}
User{age=22, name='a'}

排序后：
User{age=12, name='b'}
User{age=22, name='a'}
User{age=22, name='y'}