Converting JSONObject to Java Object

问题

I made a rest call to a service and stored the response in a JSONObject. However, I am trying to convert it to a class object and getting errors. Here's my code:

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");

Here's what the response looks like:

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

And here's what the UserIdentifier class looks like:

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;
    }
}

But I get the error:

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

What am I doing wrong?

Edit 1: Here's the attempt at using gson from the answers:

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);

But I get the error:

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

回答1:

You may need use gson

   class Name{
String resultCode;
UserIdentifier useridentifier;
//getters

}

Gson gson=new Gson();
Name name=gson.fromJson(jsonString,Name.class);

回答2:

Figured out what the problem was. Needed to extract the jsonobject instead of getting the string. Here was the line that fixed the issue:

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

回答3:

the things is that you can't cast the object that return in the get method like this, One solution could be this, using GSON library:

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

回答4:

Use Gson library

Gson gson=new GsonBuilder().create();

UserIdentifier userIdentifier=gson.fromJson(jsonString,UserIdentifier.class);

In your case jsonString is resourceResponse

For details study Gson documentation

来源：https://stackoverflow.com/questions/35210070/converting-jsonobject-to-java-object

标签

java

json

Spring

rest

jsonobject