我有两个`HashMap`，我想使用GSON进行反序列化为实体类。
void convert(){
    HashMap<String,String> map1 = new HashMap<>();
    map1.put("key1","value1");
    map1.put("key2","value2");
    HashMap<String,String> map2 = new HashMap<>();
    map2.put("key3","value3");
    map2.put("key4","value4");
    Gson gson = new Gson();
    String service = gson.toJson(map2);
    map1.put("service", service);
    String json = gson.toJson(map1);
    MyModel myModel = gson.fromJson(json, MyModel.class);
    System.out.println(gson.toJson(myModel));
}
我的实体类
public class MyModel {
    String key1;
    String key2;
    String service;
    public String getKey1() {
        return key1;
    }
    public void setKey1(String key1) {
        this.key1 = key1;
    }
    public String getKey2() {
        return key2;
    }
    public void setKey2(String key2) {
        this.key2 = key2;
    }
    public String getService() {
        return service;
    }
    public void setService(String service) {
        this.service = service;
    }
}
有没有更高效的方法来实现这个？

HashMap<String, Object> map1 = new HashMap<>();
map1.put("key1", "value1");
map1.put("key2", "value2");
HashMap<String, String> map2 = new HashMap<>();
map2.put("key3", "value3");
map2.put("key4", "value4");
map1.put("service", map2);
String result = gson.toJson(map1);

MyModel myModel = gson.fromJson(result, MyModel.class);

public class MyModel {
    String key1;
    String key2;
    Map<String, String> service;
    // ...
}