CODEWITHSUNDEEP
javaandroidjson
Milos
Milos

Reputation: 1838

Java String conversion to JSON can not be done

I have JSON which I get from server:

 "[{\"id\":\"1\",\"name\":\"Milos\",\"city\":\"Smederevo\",\"email\":\"milos\",\"password\":\"\"},
 {\"id\":\"3\",\"name\":\"Boban\",\"city\":\"Beograd\",\"email\":\"bole\",\"password\":\"\"},
 {\"id\":\"4\",\"name\":\"Pele\",\"city\":\"Brazil\",\"email\":\"[email protected]\",\"password\":\"\"},
 {\"id\":\"5\",\"name\":\"admin\",\"city\":\"Smederevo\",\"email\":\"admin\",\"password\":\"\"}]"

I am using that json and sending to my thread (android thread):

  try {
            // Method from which I am getting Json described above
            String s = dm.getAllUsers();

            /*JSONParser jp = new JSONParser();             
            JsonElement jelement = new JsonParser().parse(s);   
                JsonArray array1 = jelement.getAsJsonArray();*/

            JSONArray array = new JSONArray(s);
            for (int i = 0; i < array.length(); i++) {

                 JSONObject menuObject = array.getJSONObject(i);

                 // doing something with the object
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }

I can not process that Json at all. I am getting the error "java.lang.String cannot be converted to JSONArray". A know that problem is caused by "\", and I just do not know how to get rid of "\".

I tried:

1) s.replace("\\", "");
2) s.replace("\"", "'");
3) s.replaceAll("\\", "");
4) s.replaceAll("\"", "'");

In order to erase "\" but replace do not react at all. I also tried to solve problem with "google-gson-2.2.2" library (code under the comment above, under the method).

Any advice, please?

Upvotes: 3

Views: 7812

Answers (7)

RaviPatidar
RaviPatidar

Reputation: 1486

It is working for me...

In your json the value of "Your Json" is inclused inside "" so it's considered a string not an array..

So the solution is one of two things:

If you can modify the server response, remove the "" from arround the json array. or parse it first as string and then create a json array from that string like..

String notes = jobj.getString("GetNotesResult");
jarray = new JSONArray(notes);

Upvotes: 4

Milos
Milos

Reputation: 1838

Problem has been solved with:

 1) s = s.trim();
 2) s = s.substring(1, s.length()-1);
 3) s = s.replace("\\", "");

My json has been retrieved with "double quotes" on the beginning and on the end. I do not know how string variable can not figure out that "double quotes" is for "beginning" and for "ending" of string.

Thank you everybody for helping.

Upvotes: 4

1218985
1218985

Reputation: 8012

Your json will be valid only if you remove the back slashes () in between. You could use something like: strJson = strJson.replaceAll("\\\\", ""); OR strJson = strJson.replace("\\", ""); to remove the slashes () in between your json String. Please note that replaceAll() method treats the first argument as a regex, so you must double escape the backslash but, the replace() method treats it as a literal string, so you only have to escape it once. Please have a look at the below example for better understanding: I have kept your json text in a file named json.txt in my hard-drive for demonstration. The contents in the file looks like this:

[{\"id\":\"1\",\"name\":\"Milos\",\"city\":\"Smederevo\",\"email\":\"milos\",\"password\":\"\"},
 {\"id\":\"3\",\"name\":\"Boban\",\"city\":\"Beograd\",\"email\":\"bole\",\"password\":\"\"},
 {\"id\":\"4\",\"name\":\"Pele\",\"city\":\"Brazil\",\"email\":\"[email protected]\",\"password\":\"\"},
 {\"id\":\"5\",\"name\":\"admin\",\"city\":\"Smederevo\",\"email\":\"admin\",\"password\":\"\"}]

Now the code for getting the json array:

package com.stackoverflow.com;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;


public class JsonTest {

    public static void main(String[] args) {    

        try {
            FileReader fileReader = new FileReader("C:/Users/sarath_sivan/Desktop/json.txt");
            BufferedReader br = new BufferedReader(fileReader); 
            StringBuilder strJsonBuilder = new StringBuilder();
            String strLine; 

            while((strLine = br.readLine()) != null) { 
                strJsonBuilder.append(strLine);
            }

            String strJson = strJsonBuilder.toString();
            strJson = strJson.replaceAll("\\\\", ""); /*OR you can use strJson = strJson.replace("\\", "");*/
            JSONArray jsonArray = new JSONArray(strJson);

            for (int i = 0; i < jsonArray.length(); i++) {
                JSONObject menuObject = jsonArray.getJSONObject(i);
                System.out.println("id: " + menuObject.getInt("id"));
                System.out.println("name: " + menuObject.getString("name"));
                System.out.println("city: " + menuObject.getString("city"));
                System.out.println("email: " + menuObject.getString("email"));
                System.out.println("password: " + menuObject.getString("password"));
                System.out.println();
                // do something with your JSON
            }

            fileReader.close();

        } catch (JSONException e) {
            e.printStackTrace();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

}

Upvotes: 2

Jaya Mayu
Jaya Mayu

Reputation: 17247

I have no idea why its not working for you. Dot net web services do respond with \ but Java capable of parsing it. I did as below and it worked.

I've coded like this.

JSONArray users = null;
String jsStr =  "[{\"id\":\"1\",\"name\":\"Milos\",\"city\":\"Smederevo\",\"email\":\"milos\",\"password\":\"\"},{\"id\":\"3\",\"name\":\"Boban\",\"city\":\"Beograd\",\"email\":\"bole\",\"password\":\"\"},{\"id\":\"4\",\"name\":\"Pele\",\"city\":\"Brazil\",\"email\":\"[email protected]\",\"password\":\"\"}, {\"id\":\"5\",\"name\":\"admin\",\"city\":\"Smederevo\",\"email\":\"admin\",\"password\":\"\"}]";
try {
    users = new JSONArray(jsStr);
} catch (JSONException e) {
    e.printStackTrace();
}

Log.v("JSONStr", String.valueOf(users.length()));
for(int i = 0; i<users.length(); i++){
    try {
        Log.v("Name", users.getJSONObject(i).getString("name"));
    } catch (JSONException e) {
        e.printStackTrace();
    }
}

See the LogCat

03-18 16:34:46.459: V/JSONStr(307): 4
03-18 16:34:46.479: V/Name(307): Milos
03-18 16:34:46.479: V/Name(307): Boban
03-18 16:34:46.479: V/Name(307): Pele
03-18 16:34:46.479: V/Name(307): admin

Upvotes: 2

Pramod J George
Pramod J George

Reputation: 1723

Try this solution.

s.replaceAll("\\\\", "");

This will definitely work.

Upvotes: 5

Mzzl
Mzzl

Reputation: 4126

I don't really like the various String.replaceAll(rexex, "") solutions. What if some of the strings in your JSON contain a \ as part of the information rather than the formatting? I see a 'password' field in your JSON. I don't know whether this is going to be clear text or a hash, but in the case of the former, your program might break if a user uses a backslash in their password.

What you want to do here is unescape a string. This is a problem that as far as I can tell, can't be solved with a simple regex, but it is a problem that has been solved thousands of times before. No need to reinvent the wheel.

How to unescape a string literal in java

Upvotes: 0

Rahul
Rahul

Reputation: 45060

s = s.replace("\\", "");
System.out.println(s);

You need to assign your modified String back to s. This gives a proper parsable JSON.

Upvotes: 1

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