Java 集合类 简单Demo

package net.xxt.basic;

import java.util.Comparator;
import java.util.List;
import java.util.ArrayList;
import java.util.Collections;

/**
* 描述:List实现Comparable接口或者为其指定比较器
* 一个java文件只能有一个类是public 的，招执行时从main方法开始
* @author cjz  2009-7-29
*
*/
class User implements Comparable {
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;
}
public int compareTo(Object o) {
User user = (User) o;
int flag = this.getAge().compareTo(user.getAge());
return flag == 0 ? flag : this.getName().compareTo(user.getName());
}
}

class ComparatorUser implements Comparator {


public int compare(Object arg0, Object arg1) {
User user0 = (User) arg0;
User user1 = (User) arg1;
int flag = user0.getAge().compareTo(user1.getAge());
return flag != 0 ? flag : user0.getName().compareTo(user1.getName());
}
//定义的一个比较器

}

/**
* 描述:
* @author cjz  2009-7-29
*
*/
public class CollectionsTest {
public static void main(String[] args) {
List<User> userlist = new ArrayList<User>();
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", "3"));
userlist.add(new User("cc", "3"));
userlist.add(new User("gg", "6"));

ComparatorUser comparator = new ComparatorUser(); //创建一个比较器
  Collections.sort(userlist, comparator);
// Collections.sort(userlist);
for (int i = 0; i < userlist.size(); i++) {
User user_temp = (User) userlist.get(i);
System.out.println(user_temp.getAge() + "," + user_temp.getName());
}
}
}