Gson json parsing is not working

Question

I am parsing the files in json format where i access through

http://api.crossref.org/works?rows=1000&offset=6000000

There are around 71 million distinct publication records and the link i gave is only presents 1000. In my java code gson parser mostly works well but sometimes it gives an error as following:

com.google.gson.JsonSyntaxException: com.google.gson.stream.MalformedJsonException: Unterminated string at line 2 column 1
        at com.google.gson.internal.Streams.parse(Streams.java:56)
        at com.google.gson.JsonParser.parse(JsonParser.java:84)
        at com.google.gson.JsonParser.parse(JsonParser.java:59)
        at com.google.gson.JsonParser.parse(JsonParser.java:45)
        at connectingurl.CrossRefFullTextToTable.<init>(CrossRefFullTextToTable.java:84)
        at connectingurl.CrossRefFullTextToTable.main(CrossRefFullTextToTable.java:181)
    Caused by: com.google.gson.stream.MalformedJsonException: Unterminated string at line 2 column 1
        at com.google.gson.stream.JsonReader.syntaxError(JsonReader.java:1310)
        at com.google.gson.stream.JsonReader.nextString(JsonReader.java:1046)
        at com.google.gson.stream.JsonReader.nextValue(JsonReader.java:784)
        at com.google.gson.stream.JsonReader.objectValue(JsonReader.java:766)
        at com.google.gson.stream.JsonReader.peek(JsonReader.java:380)
        at com.google.gson.internal.bind.TypeAdapters$25.read(TypeAdapters.java:635)
        at com.google.gson.internal.bind.TypeAdapters$25.read(TypeAdapters.java:658)
        at com.google.gson.internal.bind.TypeAdapters$25.read(TypeAdapters.java:650)
        at com.google.gson.internal.bind.TypeAdapters$25.read(TypeAdapters.java:658)
        at com.google.gson.internal.bind.TypeAdapters$25.read(TypeAdapters.java:658)
        at com.google.gson.internal.bind.TypeAdapters$25.read(TypeAdapters.java:633)
        at com.google.gson.internal.Streams.parse(Streams.java:44)

As i searched for it, most probably there might be a memory issue.

Here is part of my java code:

if(code == 200){

    String full_text_link = "";
    String license = "";

    BufferedReader in = new BufferedReader(new InputStreamReader(yc.getInputStream(), "UTF-8"));
    StringBuilder sb = new StringBuilder();

    String inputLine;
    while ((inputLine = in.readLine()) != null) {
        sb.append(inputLine + System.getProperty("line.separator"));
    }
    in.close();
    String jsonLine = sb.toString();


    JsonElement jelement = new JsonParser().parse(jsonLine);     
    JsonObject  jobject = jelement.getAsJsonObject();
    jobject = jobject.getAsJsonObject("message");
    JsonArray jarray_items = jobject.getAsJsonArray("items");

    ...
}

The error comes from the line:

JsonElement jelement = new JsonParser().parse(jsonLine);

It seems gson might have such problems. is there any other suggestion to use another parser or is there something that i should add my code?

Thanks in advance...

you could use the FasterXML JSON processor as an alternative (works really well) but it is safe to assume that the error is not within GSON - either your JSON is malformed or your own code has errors. — specializt, Jan 07 '15 at 10:30

score 1 · Accepted Answer · answered Jan 07 '15 at 10:37

while ((inputLine = in.readLine()) != null) {
   sb.append(inputLine + System.getProperty("line.separator"));
}

You are basically modifying your input without reason, you cant simply pre-process your JSON without knowing the exact syntax, to solve the problem you can let GSON read the file itself, for example :

http://www.java2blog.com/2013/11/gson-example-read-and-write-json.html

package org.arpit.java2blog;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.List;
import org.arpit.java2blog.pojo.Country;
import com.google.gson.Gson;

/*
 * @Author : Arpit Mandliya
 */
public class GSONReadingFromFileExample {

 public static void main(String[] args) {

  Gson gson = new Gson();

  try {

   System.out.println("Reading JSON from a file");
   System.out.println("----------------------------");

   BufferedReader br = new BufferedReader(
     new FileReader("E:\\file.json"));

    //convert the json string back to object
   Country countryObj = gson.fromJson(br, Country.class);

   System.out.println("Name Of Country: "+countryObj.getName());


   System.out.println("Population: "+countryObj.getPopulation());

   System.out.println("States are :");

   List<String> listOfStates = countryObj.getListOfStates();
   for (int i = 0; i < listOfStates.size(); i++) {
    System.out.println(listOfStates.get(i));
   }

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

Thanks @specializt. But i am a bit confused. To retrieve the data from a URL, don't I need to convert it as text? for ex. http://stackoverflow.com/questions/7467568/parsing-json-from-url — mlee_jordan, Jan 07 '15 at 14:03

Gson json parsing is not working

1 Answers1