如何在java中制作嵌套的HashMap

import java.util.HashMap;
import java.util.Map;

public class NestedHashMapExample {
    public static void main(String[] args) {
        // 创建外层HashMap
        Map<String, Map<String, String>> nestedHashMap = new HashMap<>();

        // 创建内层HashMap
        Map<String, String> innerHashMap = new HashMap<>();
        innerHashMap.put("key1", "value1");
        innerHashMap.put("key2", "value2");

        // 将内层HashMap放入外层HashMap
        nestedHashMap.put("outerKey", innerHashMap);

        // 访问嵌套的HashMap
        String value = nestedHashMap.get("outerKey").get("key1");
        System.out.println(value); // 输出：value1
    }
}