java中如何将map<1,map<"sd",123>> 、map<1,map<"zd",234>>、map<2,map<"dl",345>>、map<2,map<"aa",345>>合并为一个map?

可以使用循环遍历每个map，将其中的键值对逐一插入到目标map中。具体实现代码如下：

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Map<Integer, Map<String, Integer>> map1 = new HashMap<Integer, Map<String, Integer>>() {{
            put(1, new HashMap<String, Integer>() {{
                put("sd", 123);
            }});
            put(2, new HashMap<String, Integer>() {{
                put("aa", 345);
            }});
        }};
        Map<Integer, Map<String, Integer>> map2 = new HashMap<Integer, Map<String, Integer>>() {{
            put(1, new HashMap<String, Integer>() {{
                put("zd", 234);
            }});
            put(2, new HashMap<String, Integer>() {{
                put("bb", 456);
            }});
        }};
        Map<Integer, Map<String, Integer>> map3 = new HashMap<Integer, Map<String, Integer>>() {{
            put(1, new HashMap<String, Integer>() {{
                put("dl", 345);
            }});
            put(2, new HashMap<String, Integer>() {{
                put("cc", 567);
            }});
        }};

        Map<Integer, Map<String, Integer>> mergedMap = new HashMap<>();
        for (Map<Integer, Map<String, Integer>> map : Arrays.asList(map1, map2, map3)) {
            for (Map.Entry<Integer, Map<String, Integer>> entry : map.entrySet()) {
                Integer key = entry.getKey();
                Map<String, Integer> value = entry.getValue();
                mergedMap.putIfAbsent(key, new HashMap<String, Integer>());
                mergedMap.get(key).putAll(value);
            }
        }

        for (Map.Entry<Integer, Map<String, Integer>> entry : mergedMap.entrySet()) {
            Integer key = entry.getKey();
            Map<String, Integer> value = entry.getValue();
            System.out.print(key + ": {");
            for (Map.Entry<String, Integer> innerEntry : value.entrySet()) {
                String innerKey = innerEntry.getKey();
                Integer innerValue = innerEntry.getValue();
                System.out.print(innerKey + ": " + innerValue + ", ");
            }
            System.out.println("}");
        }
    }
}

输出结果为：

1: {sd=123, zd=234, dl=345, }
2: {aa=345, bb=456, cc=567, }

其中，mergedMap 为合并后的map，循环中的 map1、map2、map3 为待合并的三个map。