使用Collections.sort()方法对list排序，,一个POJO例子clas

使用Collections.sort()方法对list排序，,一个POJO例子clas

一个POJO例子

class User { String name; String age; public User(String name,String age){  this.name=name;  this.age=age; } public String getAge() {  return age; } public void setAge(String age) {  this.age = age; } public String getName() {  return name; } public void setName(String name) {  this.name = name; } }

具体的比较类，实现Comparator接口

import java.util.Comparator;import java.util.List;import java.util.ArrayList;import java.util.Collections;public class ComparatorUser implements Comparator{ public int compare(Object arg0, Object arg1) {  User user0=(User)arg0;  User user1=(User)arg1;   //首先比较年龄，如果年龄相同，则比较名字  int flag=user0.getAge().compareTo(user1.getAge());  if(flag==0){   return user0.getName().compareTo(user1.getName());  }else{   return flag;  }   }}

测试类

public class SortTest { public static void main(String[] args){  List userlist=new ArrayList();  userlist.add(new User("dd","4"));  userlist.add(new User("aa","1"));  userlist.add(new User("ee","5"));  userlist.add(new User("bb","2"));    userlist.add(new User("ff","5"));  userlist.add(new User("cc","3"));  userlist.add(new User("gg","6"));  ComparatorUser comparator=new ComparatorUser();  Collections.sort(userlist, comparator);  for (int i=0;i<userlist.size();i++){   User user_temp=(User)userlist.get(i);      System.out.println(user_temp.getAge()+","+user_temp.getName());   } }}

也可以不定义Comparator类，直接将此类的实现inline，如下代码：

Collections.sort(myList, new Comparator<User>() {         public int compare(User user0, User user1) {             int flag=user0.getAge().compareTo(user1.getAge());            if(flag==0){                return user0.getName().compareTo(user1.getName());            }else{                return flag;            }          }     });

首先年龄排序，如果年龄相同，则按名字排序

结果:

   1, aa   2, bb   3, cc   4, dd   5, ee                    //注意:同样是5岁的人，则比较名字(ee,ff)，然后排序   5, ff   6, gg