What is the correct way to build JSON strings in Java so you don't get extra slash characters in result?

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I'm using Spring MVC on the back end and Bootstrap/jQuery on the front end.

My WebController's REST web service talks to a UserService, does stuff, and returns a Messages object with strings in it.

The problem is, when the JSON gets returned to the browser, it has extra \\ characters in it ...

Example:

{"readyState":4,"responseText":"{\"success\":false,\"messages\":\"{\\\"error\\\":\\\"Error modifying the user.\\\"}\"}" ...

After searching it looks like it might be nested JSON data that's causing the problem?

I'm building it like this ...

import com.fasterxml.jackson.databind.ObjectMapper;

public String toJSON() {
    String sRet = "";

    Map<String,String> messages = new HashMap<String,String>();
    messages.put("error", "Error modifying the user.");

    ObjectMapper mapper = new ObjectMapper();
    try {
        sRet = mapper.writeValueAsString(messages);
    } catch (Exception x) {
        // ...
    }

    return sRet;
}

And then returning it to the browser like this ...

@RequestMapping(value = "/json/user", method = RequestMethod.POST)
public ResponseEntity<String> modifyUser(@RequestBody String json) throws Exception {
    boolean bSuccess = true;

/* ... do the modify user stuff which builds a Messages object, and sets bSuccess = false if there's an error ... */

    JSONObject replyObj = new JSONObject();
    replyObj.put("success", bSuccess);
    replyObj.put("messages", messages.toJSON());
    return new ResponseEntity<String>(replyObj.toJSONString(), (bSuccess) ? HttpStatus.OK : HttpStatus.BAD_REQUEST);        
}

What is the correct way to build this JSONObject so it does not have all the extra slashes in it?

spring-rest objectmapper json java
1 Answers

Personally I always use GSON when dealing with JSON in java.

You are right your problem has to do with nesting JSON, you add a string that contains " to messages, it escapes those because it thinks you want the literal string like that. It doesn't know that it's also a object.

Have you tried just doing this?

replyObj.put("messages", messages);
user_51992890
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