JSON.stringify in java - android

问题:

Is there any way to perform a JSON.stringify in android?

I keep seeing JSON.stringify(JSONObject) all around the web, but I cant find the JSON class in android.

Any help?

回答1:

JSON.stringify(JSONObject) is a Javascript function and will not be available in Java. If you're using the org.json.* package built in the Android SDK, the equivalent would be to simply call toString() on your JSONObject instance, or the more human-friendly toString(int).

http://developer.android.com/reference/org/json/JSONObject.html#toString() http://developer.android.com/reference/org/json/JSONObject.html#toString(int)

JSONObject obj = ...
String jsonString = obj.toString(4);

回答2:

I know this is old, but I ran into the same problem. And there doesn't seem to be much about it here... so I thought I would add what I learned.

I used a third-party library to aid in the endeavor: org.codehaus.jackson All of the downloads for this can be found here.

For base JSON functionality, you need to add the following jars to your project's libraries: jackson-mapper-asl and jackson-core-asl

Choose the version your project needs. (Typically you can go with the latest stable build).

Once they are imported in to your project's libraries, add the following import lines to your code:

 import org.codehaus.jackson.JsonGenerationException;
 import org.codehaus.jackson.map.JsonMappingException;
 import org.codehaus.jackson.map.ObjectMapper;`

With the java object defined and assigned values that you wish to convert to JSON and return as part of a RESTful web service

User u = new User();
 u.firstName = "Sample";
 u.lastName = "User";
 u.email = "[e-mail]";

ObjectMapper mapper = new ObjectMapper();

try {
    // convert user object to json string and return it 
    return mapper.writeValueAsString(u);
}

  // catch various errors
  catch (JsonGenerationException e) {
    e.printStackTrace();
} 
  catch (JsonMappingException e) {
    e.printStackTrace();
}

The result should looks like this: {"firstName":"Sample","lastName":"User","email":"[e-mail]"}

回答3:

Basic actions with JSON objects in JAVA can be done either with a help of org.json package (included in Android SDK) or javax.json (part of JAVA EE). Both of them have toString() method for conversion of JSONObject to string:

//assuming you have object `jsonobject` of class `JSONObject`
String output = jsonobject.toString()