TreeMap练习：对学生对象的姓名进行升序排序

package map;

import java.util.*;

public class MapDemo4 {

 /**

  * @TreeMap练习

  *

  * 对学生对象的姓名进行升序排序

  *

  * 因为数据是以键值对形式存在的。

  * 所以要使用可以排序的Map集合。TreeMap。

  *

  *

  */

 public static void main(String[] args) {

  TreeMap<Student,String> tm = new TreeMap<Student,String>(new StuNameComparator());

  

  tm.put(new Student("blisi3",23),"nanjing");

  tm.put(new Student("lisi1",21),"beijing");

  tm.put(new Student("lisi1",21),"tianjing");

  tm.put(new Student("alisi4",24),"wuhan");

  tm.put(new Student("lisi2",22),"shanghai");

  

  Set<Map.Entry<Student, String>> entrySet = tm.entrySet();

  

  Iterator<Map.Entry<Student, String>> it = entrySet.iterator();

  

  while(it.hasNext()){

   Map.Entry<Student, String> me = it.next();

   

   Student stu = me.getKey();

   String addr = me.getValue();

   System.out.println(stu+"..."+addr);

  }

  

  

 }

}

class StuNameComparator implements Comparator<Student>{

 public int compare(Student s1,Student s2){

  int num = s1.getName().compareTo(s2.getName());

  if(num==0)

   return new Integer(s1.getAge()).compareTo(new Integer(s2.getAge()));

  return num;

  

 }

}