TreeMap排序

public class TreeMapTest1 {
    public static void main(String[] args) {
        Map<User,String> treeMap = new TreeMap();
        User user = new User("zhangsan", 18, 1000);
        User user2 = new User("lisi", 20, 1000);
        User user3 = new User("wangwu", 30, 500);
        treeMap.put(user, "张三");
        treeMap.put(user2, "李四");
        treeMap.put(user3, "王五");
        Set<Map.Entry<User, String>> entries = treeMap.entrySet();
        for (Map.Entry<User, String> entry : entries) {
            System.out.println(entry.getKey() + "---------" + entry.getValue());
        }
    }
}

class User implements Comparable<User> {
    String name;
    int age;
    double salary;

    public User() {
    }

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


    @Override
    public int compareTo(User o) {
        if (this.salary > o.salary) {  //递增模式反之递减
            return 1;
        } else if (this.salary < o.salary) {
            return -1;
        } else {
            if (this.age > o.age) {
                return 1;
            } else if (this.age < o.age) {
                return -1;
            } else {
                return 0;
            }
        }
    }

    @Override
    public String toString() {
        return this.name + "-" + this.age + "-" + this.salary;
    }
}