在java 8中，根据同名条件将所有hashmap放在一起。

import java.util.*;
import java.util.stream.Collectors;

public class Main {
    public static void main(String[] args) {
        // 创建包含多个HashMap的集合
        List<HashMap<String, String>> hashMapList = new ArrayList<>();
        HashMap<String, String> hashMap1 = new HashMap<>();
        hashMap1.put("name", "John");
        hashMap1.put("age", "25");
        hashMapList.add(hashMap1);
        HashMap<String, String> hashMap2 = new HashMap<>();
        hashMap2.put("name", "Jane");
        hashMap2.put("age", "30");
        hashMapList.add(hashMap2);
        HashMap<String, String> hashMap3 = new HashMap<>();
        hashMap3.put("name", "John");
        hashMap3.put("age", "35");
        hashMapList.add(hashMap3);

        // 根据同名条件将所有HashMap放在一起
        Map<String, List<HashMap<String, String>>> groupedHashMaps = hashMapList.stream()
                .flatMap(map -> map.entrySet().stream())
                .collect(Collectors.groupingBy(Map.Entry::getKey,
                        Collectors.mapping(Map.Entry::getValue, Collectors.toList())));

        // 输出结果
        for (Map.Entry<String, List<HashMap<String, String>>> entry : groupedHashMaps.entrySet()) {
            System.out.println(entry.getKey() + ": " + entry.getValue());
        }
    }
}

name: [John, Jane, John]
age: [25, 30, 35]