How to use parameters with HttpPost

Question

I am using a RESTfull webservice with this methode    POST  Consumes   application json     Path  create    public void create String str1  String str2   System out println  value 1       str1   System out println  value 2       str2       In my Android app I want to call this method  How do I give the correct values to the parameters using org apache http client methods HttpPost   I have noticed that I can use the annotation  HeaderParam and simply add headers to the HttpPost object  Is this the correct way  Doing it like   httpPost setHeader  Accept    application json    httpPost setHeader  str1    a value    httpPost setHeader  str2    another value      Using the setEntity methode on httpPost won t work  It only sets the parameter str1 with the json string  When using it like   JSONObject json   new JSONObject    json put  str1    a value    json put  str2    another value    HttpEntity e   new StringEntity json toString     httpPost setEntity e     server output  value 1     str1   a value   str2   another value

User · Answer

You can also use this approach in case you want to pass some http parameters and send a json request:

(note: I have added in some extra code just incase it helps any other future readers)

public void postJsonWithHttpParams() throws URISyntaxException, UnsupportedEncodingException, IOException {

    //add the http parameters you wish to pass
    List<NameValuePair> postParameters = new ArrayList<>();
    postParameters.add(new BasicNameValuePair("param1", "param1_value"));
    postParameters.add(new BasicNameValuePair("param2", "param2_value"));

    //Build the server URI together with the parameters you wish to pass
    URIBuilder uriBuilder = new URIBuilder("http://google.ug");
    uriBuilder.addParameters(postParameters);

    HttpPost postRequest = new HttpPost(uriBuilder.build());
    postRequest.setHeader("Content-Type", "application/json");

    //this is your JSON string you are sending as a request
    String yourJsonString = "{\"str1\":\"a value\",\"str2\":\"another value\"} ";

    //pass the json string request in the entity
    HttpEntity entity = new ByteArrayEntity(yourJsonString.getBytes("UTF-8"));
    postRequest.setEntity(entity);

    //create a socketfactory in order to use an http connection manager
    PlainConnectionSocketFactory plainSocketFactory = PlainConnectionSocketFactory.getSocketFactory();
    Registry<ConnectionSocketFactory> connSocketFactoryRegistry = RegistryBuilder.<ConnectionSocketFactory>create()
            .register("http", plainSocketFactory)
            .build();

    PoolingHttpClientConnectionManager connManager = new PoolingHttpClientConnectionManager(connSocketFactoryRegistry);

    connManager.setMaxTotal(20);
    connManager.setDefaultMaxPerRoute(20);

    RequestConfig defaultRequestConfig = RequestConfig.custom()
            .setSocketTimeout(HttpClientPool.connTimeout)
            .setConnectTimeout(HttpClientPool.connTimeout)
            .setConnectionRequestTimeout(HttpClientPool.readTimeout)
            .build();

    // Build the http client.
    CloseableHttpClient httpclient = HttpClients.custom()
            .setConnectionManager(connManager)
            .setDefaultRequestConfig(defaultRequestConfig)
            .build();

    CloseableHttpResponse response = httpclient.execute(postRequest);

    //Read the response
    String responseString = "";

    int statusCode = response.getStatusLine().getStatusCode();
    String message = response.getStatusLine().getReasonPhrase();

    HttpEntity responseHttpEntity = response.getEntity();

    InputStream content = responseHttpEntity.getContent();

    BufferedReader buffer = new BufferedReader(new InputStreamReader(content));
    String line;

    while ((line = buffer.readLine()) != null) {
        responseString += line;
    }

    //release all resources held by the responseHttpEntity
    EntityUtils.consume(responseHttpEntity);

    //close the stream
    response.close();

    // Close the connection manager.
    connManager.close();
}

User · Answer

Generally speaking an HTTP POST assumes the content of the body contains a series of key value pairs that are created  most usually  by a form on the HTML side   You don t set the values using setHeader  as that won t place them in the content body   So with your second test  the problem that you have here is that your client is not creating multiple key value pairs  it only created one and that got mapped by default to the first argument in your method   There are a couple of options you can use   First  you could change your method to accept only one input parameter  and then pass in a JSON string as you do in your second test   Once inside the method  you then parse the JSON string into an object that would allow access to the fields   Another option is to define a class that represents the fields of the input types and make that the only input parameter   For example  class MyInput       String str1      String str2       public MyInput                 getters  setters      POST  Consumes   application json     Path  create    public void create MyInput in   System out println  value 1       in getStr1     System out println  value 2       in getStr2         Depending on the REST framework you are using it should handle the de-serialization of the JSON for you   The last option is to construct a POST body that looks like   str1 value1 amp str2 value2   then add some additional annotations to your server method   public void create  QueryParam  str1   String str1                      QueryParam  str2   String str2     QueryParam doesn t care if the field is in a form post or in the URL  like a GET query    If you want to continue using individual arguments on the input then the key is generate the client request to provide named query parameters  either in the URL  for a GET  or in the body of the POST

User · Answer

To set parameters to your HttpPostRequest you can use BasicNameValuePair  something like this        HttpClient httpclient      HttpPost httpPost      ArrayList lt NameValuePair gt  postParameters      httpclient   new DefaultHttpClient        httpPost   new HttpPost  your login link          postParameters   new ArrayList lt NameValuePair gt         postParameters add new BasicNameValuePair  param1    param1 value         postParameters add new BasicNameValuePair  param2    param2 value          httpPost setEntity new UrlEncodedFormEntity postParameters   UTF-8          HttpResponse response   httpclient execute httpPost

[java] How to use parameters with HttpPost

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