java - 带键的 Gson 字符串

Question

我正在使用 Gson 将对象转换为 json 字符串，它工作正常，但是当我使用 post 将该 json 发送到 web 服务方法时，我必须在字符串中添加 post 方法的参数名称。

示例:

jsonString 我从 Gson new Gson().toJson(requestDataDTO) 获得:

{
  "req": {
    "AppId": "2",
    "ThirdParty": "3",
    "UserId": "1",
    "UserToken": "4"
  },
  "req1": {
    "AppId": "-33",
    "ThirdParty": "3",
    "UserId": "1",
    "UserToken": "4"
  }
}

我想要 jsonString :

{
  "requestDataDTO": {
    "req": {
      "AppId": "2",
      "ThirdParty": "3",
      "UserId": "1",
      "UserToken": "4"
    },
    "req1": {
      "AppId": "-33",
      "ThirdParty": "3",
      "UserId": "1",
      "UserToken": "4"
    }
  }
}

现在，我在从 Gson 获得的 json 字符串的开头添加了这个 "requestDataDTO" 字符串。

有办法实现这一点吗？

Answer 1

假设你有一个看起来像这样的对象:

package com.dominikangerer.q25077756;

import com.google.gson.annotations.SerializedName;

public class RequestDataDTO {
    // {"AppId":"2","ThirdParty":"3","UserId":"1","UserToken":"4"}

    @SerializedName("AppId")
    private String appId;
    @SerializedName("ThirdParty")
    private String thirdParty;
    @SerializedName("UserId")
    private String userId;
    @SerializedName("UserToken")
    private String userToken;

    public String getAppId() {
        return appId;
    }

    public void setAppId(String appId) {
        this.appId = appId;
    }

    public String getThirdParty() {
        return thirdParty;
    }

    public void setThirdParty(String thirdParty) {
        this.thirdParty = thirdParty;
    }

    public String getUserId() {
        return userId;
    }

    public void setUserId(String userId) {
        this.userId = userId;
    }

    public String getUserToken() {
        return userToken;
    }

    public void setUserToken(String userToken) {
        this.userToken = userToken;
    }

}

最简单、对我来说也是最易读的解决方案是创建一个包含 HashMap(键/值)的包装器/容器类，如下所示:

package com.dominikangerer.q25077756;

import java.util.HashMap;

public class RequestDataDTOContainer {

    private HashMap<String, RequestDataDTO> requestDataDTO = new HashMap<String, RequestDataDTO>();

    public HashMap<String, RequestDataDTO> getRequestDataDTO() {
        return requestDataDTO;
    }

    public void setRequestDataDTO(HashMap<String, RequestDataDTO> requestDataDTO) {
        this.requestDataDTO = requestDataDTO;
    }

    public void putRequestDataDTO(String key, RequestDataDTO value){
        this.requestDataDTO.put(key, value);
    }

}

要运行它，只需使用如下所示的 main 来测试它:

// enable pretty printing
Gson gson = new GsonBuilder().setPrettyPrinting().create();

// too lazy to fill the objects by hand
String reqJson = "{\"AppId\":\"2\",\"ThirdParty\":\"3\",\"UserId\":\"1\",\"UserToken\":\"4\"}";
String req1Json = "{\"AppId\":\"-33\",\"ThirdParty\":\"3\",\"UserId\":\"1\",\"UserToken\":\"4\"}";

// deserialize it with gson
RequestDataDTO req = gson.fromJson(reqJson, RequestDataDTO.class);
RequestDataDTO req1 = gson.fromJson(req1Json, RequestDataDTO.class);

// initiliaze the container
RequestDataDTOContainer container = new RequestDataDTOContainer();

// adding the 2 req objects with the certain key
container.putRequestDataDTO("req", req);
container.putRequestDataDTO("req1", req1);

// Print it as pretty json
System.out.println(gson.toJson(container));

如果您想添加更多元信息(例如整个元对象或类似信息)而不向该 json 添加硬编码字符串，您现在可以更加灵活。

您可以在此 github 存储库中找到整个示例:Java Stackoverflow Answers by DominikAngerer