package cn.itcast_06;

import java.util.TreeSet;

import cn.itcast_06.Student;

/*
 * 需求:请按照姓名的长度排序
 */
public class TreeSetDemo {
  public static void main(String[] args) {
    // 创建集合对象
    TreeSet<Student> ts = new TreeSet<Student>();

    // 创建学生对象
    Student s1 = new Student("linqingxia", 27);
    Student s2 = new Student("zhangguorong", 29);
    Student s3 = new Student("wanglihong", 23);
    Student s4 = new Student("linqingxia", 27);
    Student s5 = new Student("liushishi", 22);
    Student s6 = new Student("wuqilong", 40);
    Student s7 = new Student("fengqingyang", 22);
    Student s8 = new Student("linqingxia", 29);

    // 添加元素
    ts.add(s1);
    ts.add(s2);
    ts.add(s3);
    ts.add(s4);
    ts.add(s5);
    ts.add(s6);
    ts.add(s7);
    ts.add(s8);

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



package cn.itcast_06;

/*
 * 如果一个类的元素要想能够进行自然排序,就必须实现自然排序接口
 */
public class Student implements Comparable<Student> {
  private String name;
  private int age;

  public Student() {
    super();
    // TODO Auto-generated constructor stub
  }

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

  public String getName() {
    return name;
  }

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

  public int getAge() {
    return age;
  }

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

  public int compareTo(Student s) {
    // 主要条件
    int num = this.name.length() - s.name.length();
    // 姓名的长度相同,不代表姓名的内容相同
    int num2 = num == 0 ? this.name.compareTo(s.name) : num;
    // 姓名的长度和内容相同,不代表年龄相同,所以还得继续判断年龄
    int num3 = num2 == 0 ? (this.age - s.age) : num2;
    return num3;
  }
}