将JSONObject转换为Java对象

Question

我对服务进行了调用，并将响应存储在中JSONObject。但是，我试图将其转换为类对象并得到错误。这是我的代码：

RestOperations operations = /*initalize*/;
String body = /*build request body*/;
String resourceResponse = operations.postForObject(/* url */, body, String.class);
JSONObject jsonResponse = new JSONObject(resourceResponse);
UserIdentifier userIdentifier = (UserIdentifier) jsonResponse.get("userIdentifier");

响应如下所示：

{
  "userIdentifier": {
    "uid": "ee63a52cda7bf411dd8603ac196951aa77",
    "code": "63a5297e7bf411dd8603ac196951aa77",
    "retailId": "860658787",
    "pointOfEntry": "RETAIL"
  },
  "resultCode": true
}

这是UserIdentifier该类的样子：

public class UserIdentifier {
    private String uid;
    private String code;
    private String retailId;

    public UserIdentifier() {

    }

    public UserIdentifier(String uid, String code, String retailId) {
        this.uid = uid;
        this.code = code;
        this.retailId = retailId;
    }

    public String getuid() {
        return uid;
    }

    public void setuid(String uid) {
        this.uid = uid;
    }

    public String getcode() {
        return code;
    }

    public void setcode(String code) {
        this.code = code;
    }

    public String getretailId() {
        return retailId;
    }

    public void setretailId(String retailId) {
        this.retailId = retailId;
    }
}

但是我得到了错误：

java.lang.ClassCastException: org.json.JSONObject cannot be cast to app.identity.UserIdentifier

我究竟做错了什么？

编辑1： 这是从答案中使用gson的尝试：

Gson gson = new GsonBuilder().create();
String body = /*build request body*/;
String resourceResponse = operations.postForObject(/* url */, body, String.class);
JSONObject jsonResponse = new JSONObject(resourceResponse);
UserIdentifier userIdentifier = gson.fromJson(jsonResponse.getString("userIdentifier"), UserIdentifier.class);

但是我得到了错误：

org.json.JSONException: JSONObject["userIdentifier"] not a string.
    at org.json.JSONObject.getString(JSONObject.java:658) ~[json-20140107.jar:na]

Answer 1

找出问题所在。需要提取jsonobject而不是获取字符串。这是解决此问题的行：

UserIdentifier userIdentifier = gson.fromJson(jsonResponse.getJSONObject("userIdentifier").toString(), UserIdentifier.class);