How do I convert String array into Json Array

Question

I have a string array like string[] sentences which consist of sentences one in each index like This is the first message in sentences[0] and This is the second message in sentences[1] and so on. My java code to send the information to the server for sentiment analysis is like this:

OutputStreamWriter out = new OutputStreamWriter(connection.getOutputStream());  
        out.write(
                "[ " +
                "\"Can't wait for the movie\"," +
                "\"Countdown! Only ten days remaining!\" " +
                "]");
        out.flush();
        out.close();

How do I replace the texts above in the code by the string array for it's length say n?

How do I add an array of string into the following JSON?, where is the JSON? this question has nothing to do with JSON. — Vamshi Krishna Alladi
– Vamshi Krishna Alladi, Commented Feb 7, 2016 at 7:05
Got it, sorry. Anyway, how do I convert this array of string into JSON array? — madhu sudhan
– madhu sudhan, Commented Feb 7, 2016 at 7:11

Noor Nawaz · Accepted Answer · 2016-02-07 07:13:40Z

12

Use Gson library, which convert Java object to Json String

    String[] sentences=new String[3];
    sentences[0]="Hi";
    sentences[1]="Hello";
    sentences[2]="How r u?";

    Gson gson=new GsonBuilder().create();
    String jsonArray=gson.toJson(sentences);

    //["Hi","Hello","How r u?"]

    out.write(jsonArray);
    out.flush();
    out.close();

answered Feb 7, 2016 at 7:13

Noor Nawaz

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1 Comment

madhu sudhan Over a year ago

Hey, I tried that but then I got 200: bad JSON format error as the response. I tried this but I'm not sure whether it's right. It responds with neutral to all.

OutputStreamWriter out = new OutputStreamWriter(connection.getOutputStream());  out.write( "[ " + "\"+tweets[0]+\"," + "\"+tweets[1]+\" " + "]");  out.flush();  out.close();

What could be the issue?

ernest_k · Accepted Answer · 2016-02-07 07:11:33Z

0

The easiest solution is a loop:

StringBuilder sb = new StringBuilder("[");
for(int i = 0; i < array.length; i++) {
    sb.append(array[i]);
    if(i < array.length-1) {
        sb.append(",");
    }
}
out.write(sb.append("]").toString());

But this has the problem of producing potentially invalid JSON (unescaped). Hence:

The best solution, however, would be to use a proper JSON/Java binding library such as Jackson, Gson, etc.

answered Feb 7, 2016 at 7:11

ernest_k

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3 Comments

madhu sudhan Over a year ago

Hey, I tried that but then I got 200: bad JSON format error as the response. I tried this but I'm not sure whether it's right. It responds with neutral to all.

OutputStreamWriter out = new OutputStreamWriter(connection.getOutputStream());       out.write(             "[ " +             "\"+tweets[0]+\"," +             "\"+tweets[1]+\" " +             "]");     out.flush();     out.close();

What could be the issue?

ernest_k Over a year ago

As I pointed out, this can produce invalid json. That's why you're highly encouraged to use Jackson or Gson.

madhu sudhan Over a year ago

StringBuilder sb=new StringBuilder(); 			sb.append("[ \""); 			for(int x=0;x<val;x++) 			{ 				String a=xyz[x].replaceAll("[^A-Za-z0-9]"," "); 				sb.append("+"); 				sb.append(a); 				if(x < val-1)  				{ 					sb.append("+\",\""); 				} 			} 				sb.append("+\" ]"); 				System.out.println(sb.toString()); 				out.write(sb.toString());

This worked perfectly for me. Thanks a lot!

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