java 2个list合并，如果id相同的对象则属性合并到一起，不同id的对象也要保留

Question

问题遇到的现象和发生背景

想要两个list合并成同一个list，然后再当前list中相同id属性的对象进行合并，不同的也要保留

用代码块功能插入代码，请勿粘贴截图

List<Info> list1 = new ArrayList<>();
        Info info1 = new Info();
        info1.setId(1);
        info1.setCount1(100);
        Info info2 = new Info();
        info2.setId(2);
        info2.setCount1(200);
        Info info3 = new Info();
        info3.setId(3);
        info3.setCount1(300);
        list1.add(info1);
        list1.add(info2);
        list1.add(info3);

        List<Info> list2 = new ArrayList<>();
        Info info4 = new Info();
        info4.setId(1);
        info4.setCount2(100);
        Info info5 = new Info();
        info5.setId(2);
        info5.setCount2(200);
        Info info6 = new Info();
        info6.setId(4);
        info6.setCount2(400);
        list2.add(info4);
        list2.add(info5);
        list2.add(info6);

 
@Data
public class Info{
    private Integer id;
    private BigDecimal count1;
    private BigDecimal count2;
}
 

我的解答思路和尝试过的方法

我尝试根据id合并为同一个list，但是不同id的无法保留下来
例 处理完的list：[Info(id=1, count1=100, count2=100), Info(id=2, count1=200, count2=200)]
之后在根据处理完的list跟原list1，list2取差集

我想要达到的结果

最好合并后都进行保留
[Info(id=1, count1=100, count2=100), Info(id=2, count1=200, count2=200), Info(id=3, count1=300, count2=null), Info(id=4, count1=null, count2=400)]

Answer 1

import lombok.Data;

import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.List;

@Data
public class Info {
    private Integer id;
    private Integer count1;
    private Integer count2;

    public static void main(String[] args) {
        List<Info> list1 = new ArrayList<>();
        Info info1 = new Info();
        info1.setId(1);
        info1.setCount1(100);
        Info info2 = new Info();
        info2.setId(2);
        info2.setCount1(200);
        Info info3 = new Info();
        info3.setId(3);
        info3.setCount1(300);
        list1.add(info1);
        list1.add(info2);
        list1.add(info3);

        List<Info> list2 = new ArrayList<>();
        Info info4 = new Info();
        info4.setId(1);
        info4.setCount2(100);
        Info info5 = new Info();
        info5.setId(2);
        info5.setCount2(200);
        Info info6 = new Info();
        info6.setId(4);
        info6.setCount2(400);
        list2.add(info4);
        list2.add(info5);
        list2.add(info6);

        labe1:
        for (int i = 0; i < list2.size(); i++) {
            Info info_2 = list2.get(i);
            for (int j = 0; j < list1.size(); j++) {
                Info info_1 = list1.get(j);
                if (info_2.getId().equals(info_1.getId())) {
                    if (info_2.getCount1() != null) {
                        info_1.setCount1(info_2.getCount1());
                    }
                    if (info_2.getCount2() != null) {
                        info_1.setCount2(info_2.getCount2());
                    }
                    continue labe1;
                }
            }
            list1.add(info_2);
        }

        System.out.println(list1);
    }
}