List集合中的对象按照某个字段去重实现

总感觉自己太菜，还在基础上摸爬滚打。

package com.huixin;

import java.util.*;

/**
 * 根据对象属性字段给list集合去重
 *
 * @author Lance
 * @date 2017/03/14
 */
public class ListQC {
public static void main(String[] args) {
        List<User> userList = new ArrayList<User>();
        User user1 = new User("张三", "001");
        userList.add(user1);
        User user2 = new User("李四", "001");
        userList.add(user2);
        User user3 = new User("王五", "002");
        userList.add(user3);
for (User u : userList) {
            System.out.println(u.getName());
        }
        System.out.println("去重后=======>");
        List<User> userListNoDupAndSort = removeDuplicateUser(userList);
for (User u : userListNoDupAndSort) {
            System.out.println(u.getName());
        }
    }
private static ArrayList<User> removeDuplicateUser(List<User> users) {
        Set<User> set = new TreeSet<User>(new Comparator<User>() {
@Override
public int compare(User o1, User o2) {
//字符串,则按照asicc码升序排列
return o1.getUserId().compareTo(o2.getUserId());
            }
        });
        set.addAll(users);
return new ArrayList<User>(set);
    }
}
class User {
private String name;
private String userId;

public User(String name, String userId) {
this.name = name;
this.userId = userId;
    }

public String getName() {
return name;
    }

public void setName(String name) {
this.name = name;
    }

public String getUserId() {
return userId;
    }

public void setUserId(String userId) {
this.userId = userId;
    }
}

效果：

张三
李四
王五
去重后=======>
张三
王五

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List集合中的对象按照某个字段去重实现

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