package com.bjpowernode.java_learning;

import java.util.*;

/**

 * java.util.Set

 *   java.util.SortedSet;无序不可以重复，但是存进去的元素可以按照元素大小顺序自动进行排列

 *     java.utile.TreeSet;

 */

import java.text.*;

public class D89_1_SortedSet {

  public static void main(String[] args) throws ParseException{

    //创建集合

    SortedSet ss = new TreeSet();

    //添加元素

    ss.add(10);//自动装箱

    ss.add(12);

    ss.add(5);

    ss.add(78);

   

    Iterator i = ss.iterator();

    while(i.hasNext()) {

      Object element = i.next();

      System.out.println(element);

    }

    //String

    SortedSet sts = new TreeSet();

    sts.add("Jack");

    sts.add("SUN");

    sts.add("COOK");

    sts.add("LUCKY");

    Iterator i2 = sts.iterator();

    while(i2.hasNext()) {

      Object element = i2.next();

      System.out.println(element);

    }

    //日期Date

    String t1 = "2008-08-08";

    String t2 = "2009-08-08";

    String t3 = "2008-09-08";

    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");

    Date dt1 = sdf.parse(t1);

    Date dt2 = sdf.parse(t2);

    Date dt3 = sdf.parse(t3);

   

   

    SortedSet sss = new TreeSet();

    sss.add(t1);

    sss.add(t2);

    sss.add(t3);

   

    //遍历

    Iterator its = sss.iterator();

    while(its.hasNext()) {

      Object element = its.next();

      if(element instanceof Date) {

        Date d = (Date)element;

        System.out.println(sdf.format(d));

      }   

    }

  }

}

 

package com.bjpowernode.java_learning;

​


import java.util.*;

import java.lang.*;

​


public class D89_2_ImplementComparable {

  public static void main(String[] args) {

    SortedSet s = new TreeSet();

    User89 u1 = new User89(3);

    User89 u2 = new User89(45);

    User89 u3 = new User89(12);

    User89 u4 = new User89(25);

    s.add(u1);

    s.add(u2);

    s.add(u3);

    s.add(u4);

   

    Iterator i = s.iterator();

    while(i.hasNext()) {

      Object o = i.next();

      System.out.println(o.toString());

    }

  }

​


}

class User89 implements Comparable{

  int age;

  User89(int age){

    this.age = age;

  }

  public String toString() {

    return age+"";

  }

  //实现java.lang.Comparable;接口中的compareTo方法

  //该方法程序员负责，SUN提供的程序已经调用了该方法


  //需求：按照User89的年龄进行排序

  public int compareTo(Object o) {

    //编写一个规则

    int age1 = this.age;

    int age2 = ((User89)o).age;

    return age2-age1;

   

  }

}