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标题: java List 排序 Collections.sort() 对 List 排序 [打印本页]

作者: 心如止水_00 时间: 2012-10-24 13:54
标题: java List 排序 Collections.sort() 对 List 排序
/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());
  }

}
}

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