对象的分组列表,其中每个对象都是 2 个元素数组

Grouping list of objects where each object is 2 elements array

List<Object[]> values =  query.getResultList();
    //values = [obj1,obj2,obj3]
    //obj1 = "1", "01";
    //obj2 = "1", "02";
    //obj3 = "1:, "03";

Map<String, List<String>> resultMap = values.stream().collect(Collectors.groupingBy(???));

我需要一个分组为 - {"1",["01","02","03"]}

的地图

我看到的参考资料很少,但似乎没有任何效果。我应该用什么来代替“???” ?如果您需要其他任何东西,请发表评论。 提前致谢。

参考:

Shortcut for adding to List in a HashMap

如果你的对象[]是字符串[]。我想代码是这样的:

package com.test.dal;

import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

public class LTest {

    public static void main(String[] args) {
        List<String[]> values = getResultList();
        //values = [obj1,obj2,obj3]
        //obj1 = "1", "01";
        //obj2 = "1", "02";
        //obj3 = "1:, "03";

        Map<String, List<String>> resultMap = values.stream().collect(Collectors.groupingBy(o -> ((String[]) o)[0], Collectors.mapping(o -> ((String[]) o)[1], Collectors.toList())));
        System.out.println(resultMap);
    }

    public static List<String[]> getResultList() {
        String[][] inits = {
                {
                        "1", "01"
                }, {
                "1", "02"
        }, {
                "1", "03"
        }
        };
        List<String[]> tbList = Arrays.asList(inits);
        return tbList;
    }
}