Posting JSON data from txt file to URL

Question

I need to post JSON data from a text file to a url.I have not come across such a scenario.

I came across posting JSON data using HttpUrlConnection.

My JSON DATA :
{
"request": {
"header": {
"signature": "BHNUMS",
"details": {
"productCategoryCode": "01",
"specVersion": "04"
}
},
"transaction": {
"primaryAccountNumber": "8961060000402122658",
"processingCode": "725400",
"transactionAmount": "000000000200",
"transmissionDateTime": "150505141718",
"systemTraceAuditNumber": "035689",
"localTransactionTime": "141718",
"localTransactionDate": "150505",
"merchantCategoryCode": "0443",
"pointOfServiceEntryMode": "021",
"pointOfServiceConditionCode":"00",
"transactionFeeAmount":"000000000200",
"acquiringInstitutionIdentifier": "10998156762",
"track2Data":";8961060000402122658=4912?",
"retrievalReferenceNumber": "44436440441",
"merchantTerminalId": "87654     987   ",
"merchantIdentifier": "10998156762",
"merchantLocation": "688 PACIFIC HIGHWAYYY CHHHHATSWOOD NSWAU",
"transactionCurrencyCode": "840",
"additionalTxnFields": 
{ "productId": "07675018955" ,
   "externalAccountNumber":"353142040651369",
   }
}
}
} 

URL :

http://10.18.141.12:30305/transaction/v/transactionw

My Code :

public static void main(String[] args) throws IOException {
    try {

        URL url = new URL("http://10.38.141.32:30304/transaction/v2/transaction");
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setDoOutput(true);
        conn.setRequestMethod("GET");
        conn.setRequestProperty("Content-Type", "application/json");

        String input = "";

        OutputStream os = conn.getOutputStream();
        os.write(input.getBytes());
        os.flush();

        if (conn.getResponseCode() != HttpURLConnection.HTTP_CREATED) {
            throw new RuntimeException("Failed : HTTP error code : "
                + conn.getResponseCode());
        }

        BufferedReader br = new BufferedReader(new InputStreamReader(
                (conn.getInputStream())));

        String output;
        System.out.println("Output from Server .... \n");
        while ((output = br.readLine()) != null) {
            System.out.println(output);
        }

        conn.disconnect();

      } catch (MalformedURLException e) {

        e.printStackTrace();

      } catch (IOException e) {

        e.printStackTrace();

     }

    }

}

String input= "" ; // I need to pass the JSON data here but not sure how to pass it.

reading from file and setting it as a string I will be able to do. But for trial purpose I had to assign String input to the JSON data mentioned above, but due to qoutes and braces I was not able to format it as a string.

Online resources explains the data to be formated in this format ( String input="{\\"qty\\":100,\\"name\\":\\"iPad 4\\"}"; )

but I have no idea how to format such big json data manually.

I am not sure if this is right, but I am not able to see the expected output. As I am completely new to this concept I am not able to tweak the code.

If anyone could help me out it would be of great help.

Answer 1

If you have valid JSON text in the file, you do not have to parse it yourself. However, if you need to check if the JSON is valid try writing a parser a choose a parser from the world wide web. The first step is to open the file and read its contents, like so:

final StringBuilder sb = new StringBuilder();
final BufferedReader br = new BufferedReader(new FileReader("your_file_name.txt"));

String line;
while ((line = br.readLine()) != null)
    sb.append(line); // Add to string builder

final String input = br.toString(); // Write this string to the connection body
// To minimalize characters transfer it to a JSON and then some JSONWriter which doesn't format so you don't have any spacelike characters in the string

The rest you have figured out by yourself ;)

Answer 2

To hard-code the JSON as String you need to escape every single double-quote with a backslash. For example, if your JSON looks like this:

{
  "foo": "1",
  "bar": "2"
}

your String declaration has to look like this:

String put = "{ \"foo\": \"1\", \"bar\": \"2\" }";

Note: IDEs like IntelliJ IDEA will escape the string for you, if you paste it into the code.

To read the file into a String , use commons-io :

String input = FileUtils.readFileToString(new File("/path/to/your/file.json"));