Java List Stream流，去空，字段赋值，去重

罗恩呀

已于 2024-04-02 17:13:44 修改

阅读量1.1w

点赞数 2

CC 4.0 BY-SA版权

分类专栏：笔记文章标签： java list windows

于 2021-04-30 17:23:28 首次发布

本文链接：https://blog.youkuaiyun.com/weixin_44414188/article/details/116307164

笔记专栏收录该内容

5 篇文章

订阅专栏

本文介绍了如何使用Java 8的ListStream API对用户实体类进行操作，包括去除空值、属性赋值，并实现去重，展示了Stream API在处理集合数据时的高效性和简洁性。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

Java List Stream流，去空，字段赋值，去重

1.实体类

/**
 * @description 用户
 * @author ln
 */
@Data
public class User {
    
	private String id;
    private String name;
    private String nickname;
    private String sex;
    private String age;
  	private String type;
}

2.去空

public void removeEmpty() {
    
    List<User> userList=new ArrayList<>();  
    userList.add(new("1","用户1","yonghu1","女"，"22","0"));
    userList.add(new("2","用户2","yonghu2","男"，"24","0"));
	userList.add(new("3","用户3","yonghu3","女"，"24","0"));
    userList.add(new("4","用户4","yonghu4","男"，"23","0"));
    List<User> list= userList.stream()
    .filter(User -> User.getId()!=null &&  User.getName()!=null)
    .collect(Collectors.toList());
}

3.赋值

public void setValue() {
    
    List<User> userList=new ArrayList<>();  
    userList.add(new("1","用户1","yonghu1","女"，"22","0"));
    userList.add(new("2","用户2","yonghu2","男"，"24","0"));
	userList.add(new("3","用户3","yonghu3","女"，"24","0"));
    userList.add(new("4","用户4","yonghu4","男"，"23","0"));
    List<User> list= userList.stream()      
        .map(object -> {
            User user = new User();
            BeanUtils.copyProperties(object, user);
            user.setType("1");
            return user;
        })
        .collect(Collectors.toList());
}

4.去重

public void removeRepeat() {
    List<User> userList=new ArrayList<>();  
    userList.add(new("1","用户1","yonghu1","女"，"22","0"));
    userList.add(new("2","用户2","yonghu2","男"，"24","0"));
	userList.add(new("3","用户3","yonghu3","女"，"24","0"));
    userList.add(new("4","用户4","yonghu4","男"，"23","0"));
	// 去重
    userList= userList.stream().collect(
                Collectors.collectingAndThen(
                Collectors.toCollection(() -> new TreeSet<>
                (Comparator.comparing(User::getId))), ArrayList::new)
        );
}