Sending and Parsing Response using HTTP Client for a JSON List

Question

With in my java code, I need to send a http post request to a specific URL with 3 headers:

URL: http://localhost/something
Referer: http://localhost/something 
Authorization: Basic (with a username and password)
Content-type: application/json

This returns a response with a JSON "key":"value" pair in it that I then need to parse somehow to store the key/value (Alan/72) in a MAP. The response is (when using SOAPUI or Postman Rest):

    {
    "analyzedNames": [
        {
            "alternate": false               
        }
    ],
    "nameResults": [
        {
            "alternate": false,            
            "givenName": "John",           
            "nameCategory": "PERSONAL",
            "originalGivenName": "",
            "originalSurname": "",           
            "score": 72,
            "scriptType": "NOSCRIPT",            
        }
    ]
}

I can do this using SOAPUI or Postman Rest but how can I do this within Java as I'm getting an error:

****DEBUG main org.apache.http.impl.conn.DefaultClientConnection - Receiving response: HTTP/1.1 500 Internal Server Error****

My code is:

    public class NameSearch {

        /**
         * @param args
         * @throws IOException 
         * @throws ClientProtocolException 
         */
        public static void main(String[] args) throws ClientProtocolException, IOException {
            // TODO Auto-generated method stub
            DefaultHttpClient defaultHttpClient = new DefaultHttpClient();          
            StringWriter writer = new StringWriter();

            //Define a postRequest request
            HttpPost postRequest = new HttpPost("http://127.0.0.1:1400/dispatcher/api/rest/search");

            //Set the content-type header
            postRequest.addHeader("content-type", "application/json");
 postRequest.addHeader("Authorization", "Basic ZW5zYWRtaW46ZW5zYWRtaW4=");

            try {               

                //Set the request post body
                StringEntity userEntity = new StringEntity(writer.getBuffer().toString());
                postRequest.setEntity(userEntity);

                //Send the request; return the response in HttpResponse object if any
                HttpResponse response = defaultHttpClient.execute(postRequest);

                //verify if any error code first
                int statusCode = response.getStatusLine().getStatusCode();                
            }
            finally
            {
                //Important: Close the connect
                defaultHttpClient.getConnectionManager().shutdown();
            }    
        }    
    }

Any help (with some sample code including which libraries to import) will be most appreciated.

THANKS

Kerem Baydoğan · Accepted Answer · 2018-05-09 21:29:36Z

34

Yes, you can do it with java

You need apache HTTP client library http://hc.apache.org/ and commons-io

HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost("http://localhost/something");


post.setHeader("Referer", "http://localhost/something");
post.setHeader("Authorization", "Basic (with a username and password)");
post.setHeader("Content-type", "application/json");

// if you need any parameters
List<NameValuePair> urlParameters = new ArrayList<NameValuePair>();
urlParameters.add(new BasicNameValuePair("paramName", "paramValue"));
post.setEntity(new UrlEncodedFormEntity(urlParameters));

HttpResponse response = client.execute(post);

HttpEntity entity = response.getEntity();
Header encodingHeader = entity.getContentEncoding();

// you need to know the encoding to parse correctly
Charset encoding = encodingHeader == null ? StandardCharsets.UTF_8 : 
Charsets.toCharset(encodingHeader.getValue());

// use org.apache.http.util.EntityUtils to read json as string
String json = EntityUtils.toString(entity, StandardCharsets.UTF_8);

JSONObject o = new JSONObject(json);

edited May 9, 2018 at 21:29

Kerem Baydoğan

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answered Dec 4, 2013 at 12:58

Georgy Gobozov

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11 Comments

Global Dictator Over a year ago

HI, I'm getting an error code of 403 which means that the request failed the authentication. Can I do for authentication? I believe that getCredentialsProvider() is depricated..so is there an alternate to this method in HttpClient API??

Georgy Gobozov Over a year ago

Usually you can use depricated method anyway. If you do not want you can try this hc.apache.org/httpcomponents-client-4.3.x/tutorial/html/… (I suppose you got last version http client)

Global Dictator Over a year ago

following your suggestion, I'm getting an error and I've added to my original question above along with my code. Could you suggest anything?

Jules Over a year ago

There are a lot of java libraries for handling JSON. "jackson" is a good place to start.

ben26941 Over a year ago

You probably want to say: String json = EntityUtils.toString(entity, encoding);

|

Andrew Regan · Accepted Answer · 2019-09-08 18:05:44Z

I recommend http-request built on Apache HTTP API.

HttpRequest<String> httpRequest = HttpRequestBuilder.createPost(yourUri
  new TypeReference<Map<String, List<Map<String, Object>>>>{})
         .basicAuth(userName, password)
         .addContentType(ContentType.APPLICATION_JSON)
         .build();

public void send(){
   ResponseHandler<String> responseHandler = httpRequest.executeWithBody(yourJsonData);
   int statusCode = responseHandler.getStatusCode();
   Map<String, List<Map<String, Object>>> response = responseHandler.get(); // Before calling the get () method, make sure the response is present: responseHandler.hasContent()

   System.out.println(response.get("nameResults").get(0).get("givenName")); //John

}

I highly recommend reading the documentation before use.

Note: You can create your custom type instead of Map to parse response. See my answer here.

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