Java自然排序Comparable使用方法解析

public class TreeSetDemo {
  public static void main(String[] args) {
    //创建集合对象
    TreeSet<Student> treeSet = new TreeSet<Student>();

    //创建学生对象
    Student s1 = new Student("xishi",29);
    Student s2 = new Student("wangzhaojun",30);
    Student s3 = new Student("diaocan",28);
    Student s4 = new Student("yangyuhuan",31);

    //添加元素
    treeSet.add(s1);
    treeSet.add(s2);
    treeSet.add(s3);
    treeSet.add(s4);

    //遍历
    for (Student s : treeSet){
      System.out.println(s);
    }
  }
}

@Override
  public int compareTo(Student o) {
    return 0;
  }
  /*
    运行结果：xishi,29
   */

@Override
  public int compareTo(Student o) {
    return 1;
  }
  /*
    运行结果：
        xishi,29
        wangzhaojun,30
        diaocan,28
        yangyuhuan,31
   */

@Override
  public int compareTo(Student o) {
    return -1;
  }
  /*
    运行结果：
        yangyuhuan,31
        diaocan,28
        wangzhaojun,30
        xishi,29
   */

@Override
  public int compareTo(Student s) {
    int num = this.age - s.age;
    return num;
  }
  /*
    运行结果：
        diaocan,28
        xishi,29
        wangzhaojun,30
        yangyuhuan,31
   */

//操作类代码
public class TreeSetDemo {
  public static void main(String[] args) {
    //创建集合对象
    TreeSet<Student> treeSet = new TreeSet<Student>();

    //创建学生对象
    Student s1 = new Student("xishi",29);
    Student s2 = new Student("wangzhaojun",30);
    Student s3 = new Student("diaocan",28);
    Student s4 = new Student("yangyuhuan",31);
    Student s5 = new Student("linqingxia",31);

    //添加元素
    treeSet.add(s1);
    treeSet.add(s2);
    treeSet.add(s3);
    treeSet.add(s4);
    treeSet.add(s5);

    //遍历
    for (Student s : treeSet){
      System.out.println(s.getName()+","+s.getAge());
    }
  }
}

//学生类中重写代码部分及运行结果
@Override
  public int compareTo(Student s) {
    int num = this.age - s.age;
    //如果年龄相同则比较姓名字母顺序(升序)排列。
    int num2 = num == 0 ? this.name.compareTo(s.name) : num;
    return num2;
  }
  /*
    运行结果：
        diaocan,28
        xishi,29
        wangzhaojun,30
        linqingxia,31
        yangyuhuan,31
   */