Develop Reference

POST JSON to Server and Receive Response

I have a class, called FindMeARestaurantDAO, which contains methods that will make network calls to a server with AsyncTask inner classes in my Activity. I am having issues with my POST request Method, which is as follows:
#Override
public String findMeARestaurant(List<CheckboxDTO> filters) {
String inputLine;
String errors;
String result;
try
{
// For each CheckboxDTO, get the Id and add it to JSONArray
JSONArray checkboxJSONArray = new JSONArray();
for (CheckboxDTO checkbox : filters)
{
try
{
// Create JSONObject
JSONObject object = new JSONObject();
// Build the object
object.put("id", checkbox.getId());
// Add object to JSONArray
checkboxJSONArray.put(object);
}
catch (Exception e)
{
e.printStackTrace();
}
}
// Put JSONArray into wrapping JSONObject
JSONObject serverObject = new JSONObject();
try
{
// Create wrapping JSONObject
serverObject.put("filtersIds", checkboxJSONArray);
}
catch (Exception e)
{
e.printStackTrace();
}
// Create URL object to hold URL
URL findMeARestaurantURL = new URL(findMeARestaurantsURL);
// Create connection to server
HttpURLConnection connection = (HttpURLConnection) findMeARestaurantURL.openConnection();
// Set request method and timeouts
connection.setRequestMethod(FIND_RESTAURANT_REQUEST_METHOD);
connection.setRequestProperty("Content-Type", "application/json; utf-8");
connection.setRequestProperty("Accept", "application/json");
connection.setChunkedStreamingMode(0);
connection.setDoOutput(true);
connection.setReadTimeout(READ_TIMEOUT);
connection.setConnectTimeout(CONNECTION_TIMEOUT);
// Connect to server
connection.connect();
// Create Writer
Writer writer = new BufferedWriter(new OutputStreamWriter(connection.getOutputStream()));
writer.write(String.valueOf(serverObject));
// Close Writer
writer.close();
// Create InputStreamReader to read response from server
InputStreamReader streamReader = new InputStreamReader(connection.getInputStream(), "utf-8");
// Create BufferedReader to read through InputStream
BufferedReader reader = new BufferedReader(streamReader);
// Create StringBuilder to hold our result
StringBuilder stringBuilder = new StringBuilder();
// Check if the line read is null
while ((inputLine = reader.readLine()) != null){
stringBuilder.append(inputLine);
}
// Close out InputStream and BufferedReader
reader.close();
streamReader.close();
// Set result to stringBuilder
result = stringBuilder.toString();
connection.disconnect();
}
catch (IOException e)
{
e.printStackTrace();
return null;
}
return result;
}
The method is POST and it appears to send the JSON serverObject to the server when I run my application, but it fails on the InputStreamReader and returns a FileNotFoundException. The server was set up by a partner for this project and says this portion of the API should be working. Am I missing something for the POST request? Do I need to be doing something differently for reading the server's response? Any help would be greatly appreciated.

The solution to this issue was in how I sent the data to the server in a POST request. I had to send my filters' Ids to the server by adding them to my URL before establishing the connection. My modified method iterates through each CheckboxDTO and catches the Id, then adds it to an array, which is then added to the URL:
#Override
public String findMeARestaurant(List<CheckboxDTO> filters) {
String inputLine;
String result;
try
{
// For each CheckboxDTO, get the Id and add it to String Array
int checkboxArray[] = new int[filters.size()];
int i = 0;
for (CheckboxDTO checkbox : filters)
{
try
{
int id = checkbox.getId();
checkboxArray[i] = id;
i++;
}
catch (Exception e)
{
e.printStackTrace();
}
}
// Add filters to end of URL for POST Request
findMeARestaurantsURL += "?filterIds=";
for (i = 0; i < checkboxArray.length; i++)
{
if (i+1 != checkboxArray.length)
{
findMeARestaurantsURL += checkboxArray[i] + ",";
}
else
{
findMeARestaurantsURL += checkboxArray[i];
}
}
// Create URL object to hold URL
URL findMeARestaurantURL = new URL(findMeARestaurantsURL);
// Create connection to server
HttpURLConnection connection = (HttpURLConnection) findMeARestaurantURL.openConnection();
// Set request method and timeouts
connection.setRequestMethod(FIND_RESTAURANT_REQUEST_METHOD);
connection.setRequestProperty("Content-Type", "application/json; utf-8");
connection.setRequestProperty("Accept", "application/json");
connection.setChunkedStreamingMode(0);
connection.setDoOutput(true);
connection.setReadTimeout(READ_TIMEOUT);
connection.setConnectTimeout(CONNECTION_TIMEOUT);
// Connect to server
connection.connect();
// Create InputStreamReader to read response from server
InputStreamReader streamReader = new InputStreamReader(connection.getInputStream(), "utf-8");
// Create BufferedReader to read through InputStream
BufferedReader reader = new BufferedReader(streamReader);
// Create StringBuilder to hold our result
StringBuilder stringBuilder = new StringBuilder();
// Check if the line read is null
while ((inputLine = reader.readLine()) != null){
stringBuilder.append(inputLine);
}
// Close out InputStream and BufferedReader
reader.close();
streamReader.close();
// Set result to stringBuilder
result = stringBuilder.toString();
connection.disconnect();
}
catch (IOException e)
{
e.printStackTrace();
return null;
}
return result;
}
The server uses the Spring framework, and according to my partner, did not use a JSONObject.

How to Return html content to view?

So i have a problem in which i had to redirect to a url with headers. However , powers beyond my control taught that when one redirects the headers are lost . The only way to do it is to make the ui create that request with the headers .
However after a bit of googling i found out that if i create a get request at backend i can include the headers and it will return the entire html page which can be converted into response string .
So the question would be that is it possible to take that html content , wrap it in a view and then send it back ?
My code looks like this and it is working :
#GetMapping(value="/")
public RedirectView home(Model model) {
URL url;
try {
Credentials cred=new Credentials();
url = new URL(cred.getLinkedInUrl()+"?"+"client_id="+cred.getAppid()
+"&grant_type=client_credentials&response_type=code&scope=r_liteprofile+r_emailaddress&redirect_uri="+cred.getRedirect_uri());
HttpURLConnection con = (HttpURLConnection) url.openConnection();
con.setRequestMethod("GET");
con.setRequestProperty("Accept-Language", "it-it");
BufferedReader br = new BufferedReader(
new InputStreamReader(con.getInputStream()));
String inputLine;
while ((inputLine = br.readLine()) != null) {
System.out.println(inputLine);
}
br.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
model.addAttribute("credentials", new Credentials());
return new RedirectView("someurl");
}

How to call `POST` RESTfull methods in Android?

I have developed a web service in Java. Below is a method of it.
#Path("/setup")
public class SetupJSONService {
#POST
#Path("/insertSetup")
#Consumes(MediaType.APPLICATION_JSON)
public String insertSetup(SetupBean bean)
{
System.out.println("Printed");
SetupInterface setupInterface = new SetupImpl();
String insertSetup = setupInterface.insertSetup(bean);
return insertSetup;
}
}
Below is how I call this method using Java Jersey in my computer.
Client client = ClientBuilder.newClient();
WebTarget target = client.target("http://localhost:8080/TestApp/rest/setup").path("/insertSetup");
SetupBean setupBean = new SetupBean();
setupBean.setIdPatient(1);
setupBean.setCircleType(1);
target.request(MediaType.APPLICATION_JSON_TYPE).post(Entity.entity(setupBean, MediaType.APPLICATION_JSON_TYPE));
However, Now this method should be called in Android as well, but I'm not sure how to do that. I know how to make GET calls in android like below.
public static String httpGet(String urlStr) throws IOException {
URL url = new URL(urlStr);
HttpURLConnection conn =
(HttpURLConnection) url.openConnection();
if (conn.getResponseCode() != 200) {
throw new IOException(conn.getResponseMessage());
}
// Buffer the result into a string
BufferedReader rd = new BufferedReader(
new InputStreamReader(conn.getInputStream()));
StringBuilder sb = new StringBuilder();
String line;
while ((line = rd.readLine()) != null) {
sb.append(line);
}
rd.close();
conn.disconnect();
return sb.toString();
}
But since my method is POST and since it accept a Java Bean and it does return a String, how can I handle this in Android? Not interested using Jersey in android as it does have bad comments in Android environment.

Android provides a way to do what you want, but this is not a productive way, i like to use retrofit 2 to power my development and to write a better code.
Here a example of retrofit 2 that can help you =) :
add to your dependencies in build.gradle
dependencies {
compile 'com.google.code.gson:gson:2.6.2'
compile 'com.squareup.retrofit2:retrofit:2.0.2'
compile 'com.squareup.retrofit2:converter-gson:2.0.2'
}
Create your retrofit builder that specifies a converter and a base url.
public static final String URL = "http://localhost:8080/TestApp/rest/";
Retrofit retrofit = new Retrofit.Builder()
.baseUrl(URL)
.addConverterFactory(GsonConverterFactory.create())
.build();
Now create a Interface that will encapsulate your rest methods like below
public interface YourEndpoints {
#POST("setup/insertSetup")
Call<ResponseBody> insertSetup(#Body SetupBean setupBean);
}
Associate your endpoints interface with your retrofit instance.
YourEndpoints request = retrofit.create(YourEndpoints.class);
Call<ResponseBody> yourResult = request.insertSetup(YourSetupBeanObject);
yourResult.enqueue(new Callback<ResponseBody>() {
#Override
public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
//response.code()
//your string response response.body().string()
}
#Override
public void onFailure(Throwable t) {
//do what you have to do if it return a error
}
});
Ref to this links for more information:
http://square.github.io/retrofit/
https://github.com/codepath/android_guides/wiki/Consuming-APIs-with-Retrofit

that`s the code for the normal way you want
InputStream is = null;
OutputStream os = null;
HttpURLConnection con = null;
try {
//constants
URL url = new URL("http://localhost:8080/TestApp/rest/");
//Map your object to JSONObject and convert it to a json string
String message = new JSONObject().toString();
con = (HttpURLConnection) url.openConnection();
con.setReadTimeout(1000);
con.setConnectTimeout(15000);
con.setRequestMethod("POST");
con.setDoInput(true);
con.setDoOutput(true);
con.setFixedLengthStreamingMode(message.getBytes().length);
con.setRequestProperty("Content-Type", "application/json;charset=utf-8");
//open
con.connect();
//setup send
os = new BufferedOutputStream(con.getOutputStream());
os.write(message.getBytes());
//clean up
os.flush();
//do somehting with response
is = con.getInputStream();
String contentAsString = readData(is,len);
os.close();
is.close();
con.disconnect();
} catch (Exception e){
try {
os.close();
is.close();
con.disconnect();
} catch (IOException e1) {
e1.printStackTrace();
}
}

Invoking servlet from java main method

import java.net.*;
import java.io.*;
public class sample
{
public static void main (String args[])
{
String line;
try
{
URL url = new URL( "http://localhost:8080/WeighPro/CommPortSample" );
BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream()));
line = in.readLine();
System.out.println( line );
in.close();
}
catch (Exception e)
{
System.out.println("Hello Project::"+e.getMessage());
}
}
}
My Servlet is invoking another Jsp page like the below,
RequestDispatcher rd=request.getRequestDispatcher("index.jsp");
rd.forward(request, response);
I am not getting any reaction/output in the browser, where the servlet has to be executed once it is invoked.
Am I missing any basic step for this process? Please Help!!!

If you want to open it in browser try this
java.awt.Desktop.getDesktop().browse(java.net.URI.create("http://localhost:8080/WeighPro/CommPortSample"));

You question is not clear. Do you actually want to invoke a Servlet from the Main method, or do you want to make an HTTP request to your web application?
If you want to make an HTTP request, I can't see any obvious problems with your code above, which makes me believe that the problem is in the Servlet. You also mention that you don't get anything in the browser, but running your program above does not involve a browser.
Do you mean that you don't get a response when you go to
http://localhost:8080/WeighPro/CommPortSample
in a browser?
As Suresh says, you cannot call a Servlet directly from a main method.
Your Servlet should instead call methods on other classes, and those other classes should be callable from the main method, or from Test Cases. You need to architect your application to make that possible.

import java.io.BufferedInputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
public class OutBoundSimul {
public static void main(String[] args) {
sendReq();
}
public static void sendReq() {
String urlString = "http://ip:port/applicationname/servletname";
String respXml = text;
URL url = null;
HttpURLConnection urlConnection = null;
OutputStreamWriter out = null;
BufferedInputStream inputStream = null;
try {
System.out.println("URL:"+urlString);
url = new URL(urlString);
urlConnection = (HttpURLConnection)url.openConnection();
urlConnection.setDoInput(true);
urlConnection.setDoOutput(true);
urlConnection.setRequestMethod("POST");
System.out.println("SendindData");
out = new OutputStreamWriter(urlConnection.getOutputStream());
System.out.println("Out:"+out);
out.write(respXml);
out.flush();
inputStream = new BufferedInputStream(urlConnection.getInputStream());
int character = -1;
StringBuffer sb = new StringBuffer();
while ((character = inputStream.read()) != -1) {
sb.append((char) character);
}
System.out.println("Resp:"+sb.toString());
} catch (Exception e) {
e.printStackTrace();
}
}
}

Invoking Servlet with query parameters Form Main method
Java IO
public static String accessResource_JAVA_IO(String httpMethod, String targetURL, String urlParameters) {
HttpURLConnection con = null;
BufferedReader responseStream = null;
try {
if (httpMethod.equalsIgnoreCase("GET")) {
URL url = new URL( targetURL+"?"+urlParameters );
responseStream = new BufferedReader(new InputStreamReader( url.openStream() ));
}else if (httpMethod.equalsIgnoreCase("POST")) {
con = (HttpURLConnection) new URL(targetURL).openConnection();
// inform the connection that we will send output and accept input
con.setDoInput(true); con.setDoOutput(true); con.setRequestMethod("POST");
con.setUseCaches(false); // Don't use a cached version of URL connection.
con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
con.setRequestProperty("Content-Length", Integer.toString(urlParameters.getBytes().length));
con.setRequestProperty("Content-Language", "en-US");
DataOutputStream requestStream = new DataOutputStream ( con.getOutputStream() );
requestStream.writeBytes(urlParameters);
requestStream.close();
responseStream = new BufferedReader(new InputStreamReader( con.getInputStream(), "UTF-8" ));
}
StringBuilder response = new StringBuilder(); // or StringBuffer if not Java 5+
String line;
while((line = responseStream.readLine()) != null) {
response.append(line).append('\r');
}
responseStream.close();
return response.toString();
} catch (Exception e) {
e.printStackTrace(); return null;
} finally {
if(con != null) con.disconnect();
}
}
Apache Commons using commons-~.jar
{httpclient, logging}
public static String accessResource_Appache_commons(String url){
String response_String = null;
HttpClient client = new HttpClient();
GetMethod method = new GetMethod( url );
// PostMethod method = new PostMethod( url );
method.setRequestHeader("Content-type", "text/xml; charset=ISO-8859-1");
method.setQueryString(new NameValuePair[] {
new NameValuePair("param1","value1"),
new NameValuePair("param2","value2")
}); //The pairs are encoded as UTF-8 characters.
try{
int statusCode = client.executeMethod(method);
System.out.println("Status Code = "+statusCode);
//Get data as a String OR BYTE array method.getResponseBody()
response_String = method.getResponseBodyAsString();
method.releaseConnection();
} catch(IOException e) {
e.printStackTrace();
}
return response_String;
}
Apache using httpclient.jar
public static String accessResource_Appache(String url) throws ClientProtocolException, IOException{
try {
CloseableHttpClient httpclient = HttpClients.createDefault();
URIBuilder builder = new URIBuilder( url )
.addParameter("param1", "appache1")
.addParameter("param2", "appache2");
HttpGet method = new HttpGet( builder.build() );
// HttpPost method = new HttpPost( builder.build() );
// Create a custom response handler
ResponseHandler<String> responseHandler = new ResponseHandler<String>() {
#Override
public String handleResponse( final HttpResponse response) throws IOException {
int status = response.getStatusLine().getStatusCode();
if (status >= 200 && status < 300) {
HttpEntity entity = response.getEntity();
return entity != null ? EntityUtils.toString(entity) : null;
}
return "";
}
};
return httpclient.execute( method, responseHandler );
} catch (URISyntaxException e) {
e.printStackTrace();
}
return null;
}
JERSY using JARS {client, core, server}
public static String accessResource_JERSY( String url ){
ClientConfig config = new DefaultClientConfig();
Client client = Client.create(config);
WebResource service = client.resource( url );
ClientResponse response = service.accept(MediaType.TEXT_PLAIN).get(ClientResponse.class);
if (response.getStatus() != 200) {
System.out.println("GET request failed >> "+ response.getStatus());
}else{
String str = response.getEntity(String.class);
if(str != null && !str.equalsIgnoreCase("null") && !"".equals(str)){
return str;
}
}
return "";
}
Java Main method
public static void main(String[] args) throws IOException {
String targetURL = "http://localhost:8080/ServletApplication/sample";
String urlParameters = "param1=value11&param2=value12";
String response = "";
// java.awt.Desktop.getDesktop().browse(java.net.URI.create( targetURL+"?"+urlParameters ));
// response = accessResource_JAVA_IO( "POST", targetURL, urlParameters );
// response = accessResource_Appache_commons( targetURL );
// response = accessResource_Appache( targetURL );
response = accessResource_JERSY( targetURL+"?"+urlParameters );
System.out.println("Response:"+response);
}

Simply you cannot do that.
A response and request pair will generated by web container. You cannot generate a response object and send to the browser.
By the way which client/browser you are expecting to get the response ? No idea. Right ?
When container receives a request from client then it generates response object and serves you can access that response in service method.
If you want to see/test the response, you have to request from there.

Java HTTPS Client [duplicate]

I'm trying to find Java's equivalent to Groovy's:
String content = "http://www.google.com".toURL().getText();
I want to read content from a URL into string. I don't want to pollute my code with buffered streams and loops for such a simple task. I looked into apache's HttpClient but I also don't see a one or two line implementation.

Now that some time has passed since the original answer was accepted, there's a better approach:
String out = new Scanner(new URL("http://www.google.com").openStream(), "UTF-8").useDelimiter("\\A").next();
If you want a slightly fuller implementation, which is not a single line, do this:
public static String readStringFromURL(String requestURL) throws IOException
{
try (Scanner scanner = new Scanner(new URL(requestURL).openStream(),
StandardCharsets.UTF_8.toString()))
{
scanner.useDelimiter("\\A");
return scanner.hasNext() ? scanner.next() : "";
}
}

This answer refers to an older version of Java. You may want to look at ccleve's answer.
Here is the traditional way to do this:
import java.net.*;
import java.io.*;
public class URLConnectionReader {
public static String getText(String url) throws Exception {
URL website = new URL(url);
URLConnection connection = website.openConnection();
BufferedReader in = new BufferedReader(
new InputStreamReader(
connection.getInputStream()));
StringBuilder response = new StringBuilder();
String inputLine;
while ((inputLine = in.readLine()) != null)
response.append(inputLine);
in.close();
return response.toString();
}
public static void main(String[] args) throws Exception {
String content = URLConnectionReader.getText(args[0]);
System.out.println(content);
}
}
As #extraneon has suggested, ioutils allows you to do this in a very eloquent way that's still in the Java spirit:
InputStream in = new URL( "http://jakarta.apache.org" ).openStream();
try {
System.out.println( IOUtils.toString( in ) );
} finally {
IOUtils.closeQuietly(in);
}

Or just use Apache Commons IOUtils.toString(URL url), or the variant that also accepts an encoding parameter.

There's an even better way as of Java 9:
URL u = new URL("http://www.example.com/");
try (InputStream in = u.openStream()) {
return new String(in.readAllBytes(), StandardCharsets.UTF_8);
}
Like the original groovy example, this assumes that the content is UTF-8 encoded. (If you need something more clever than that, you need to create a URLConnection and use it to figure out the encoding.)

Now that more time has passed, here's a way to do it in Java 8:
URLConnection conn = url.openConnection();
try (BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream(), StandardCharsets.UTF_8))) {
pageText = reader.lines().collect(Collectors.joining("\n"));
}

Additional example using Guava:
URL xmlData = ...
String data = Resources.toString(xmlData, Charsets.UTF_8);

Java 11+:
URI uri = URI.create("http://www.google.com");
HttpRequest request = HttpRequest.newBuilder(uri).build();
String content = HttpClient.newHttpClient().send(request, BodyHandlers.ofString()).body();

If you have the input stream (see Joe's answer) also consider ioutils.toString( inputstream ).
http://commons.apache.org/io/api-1.4/org/apache/commons/io/IOUtils.html#toString(java.io.InputStream)

The following works with Java 7/8, secure urls, and shows how to add a cookie to your request as well. Note this is mostly a direct copy of this other great answer on this page, but added the cookie example, and clarification in that it works with secure urls as well ;-)
If you need to connect to a server with an invalid certificate or self signed certificate, this will throw security errors unless you import the certificate. If you need this functionality, you could consider the approach detailed in this answer to this related question on StackOverflow.
Example
String result = getUrlAsString("https://www.google.com");
System.out.println(result);
outputs
<!doctype html><html itemscope="" .... etc
Code
import java.net.URL;
import java.net.URLConnection;
import java.io.BufferedReader;
import java.io.InputStreamReader;
public static String getUrlAsString(String url)
{
try
{
URL urlObj = new URL(url);
URLConnection con = urlObj.openConnection();
con.setDoOutput(true); // we want the response
con.setRequestProperty("Cookie", "myCookie=test123");
con.connect();
BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
StringBuilder response = new StringBuilder();
String inputLine;
String newLine = System.getProperty("line.separator");
while ((inputLine = in.readLine()) != null)
{
response.append(inputLine + newLine);
}
in.close();
return response.toString();
}
catch (Exception e)
{
throw new RuntimeException(e);
}
}

Here's Jeanne's lovely answer, but wrapped in a tidy function for muppets like me:
private static String getUrl(String aUrl) throws MalformedURLException, IOException
{
String urlData = "";
URL urlObj = new URL(aUrl);
URLConnection conn = urlObj.openConnection();
try (BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream(), StandardCharsets.UTF_8)))
{
urlData = reader.lines().collect(Collectors.joining("\n"));
}
return urlData;
}

URL to String in pure Java
Example call to get payload from http get call
String str = getStringFromUrl("YourUrl");
Implementation
You can use the method described in this answer, on How to read URL to an InputStream and combine it with this answer on How to read InputStream to String.
The outcome will be something like
public String getStringFromUrl(URL url) throws IOException {
return inputStreamToString(urlToInputStream(url,null));
}
public String inputStreamToString(InputStream inputStream) throws IOException {
try(ByteArrayOutputStream result = new ByteArrayOutputStream()) {
byte[] buffer = new byte[1024];
int length;
while ((length = inputStream.read(buffer)) != -1) {
result.write(buffer, 0, length);
}
return result.toString(UTF_8);
}
}
private InputStream urlToInputStream(URL url, Map<String, String> args) {
HttpURLConnection con = null;
InputStream inputStream = null;
try {
con = (HttpURLConnection) url.openConnection();
con.setConnectTimeout(15000);
con.setReadTimeout(15000);
if (args != null) {
for (Entry<String, String> e : args.entrySet()) {
con.setRequestProperty(e.getKey(), e.getValue());
}
}
con.connect();
int responseCode = con.getResponseCode();
/* By default the connection will follow redirects. The following
* block is only entered if the implementation of HttpURLConnection
* does not perform the redirect. The exact behavior depends to
* the actual implementation (e.g. sun.net).
* !!! Attention: This block allows the connection to
* switch protocols (e.g. HTTP to HTTPS), which is <b>not</b>
* default behavior. See: https://stackoverflow.com/questions/1884230
* for more info!!!
*/
if (responseCode < 400 && responseCode > 299) {
String redirectUrl = con.getHeaderField("Location");
try {
URL newUrl = new URL(redirectUrl);
return urlToInputStream(newUrl, args);
} catch (MalformedURLException e) {
URL newUrl = new URL(url.getProtocol() + "://" + url.getHost() + redirectUrl);
return urlToInputStream(newUrl, args);
}
}
/*!!!!!*/
inputStream = con.getInputStream();
return inputStream;
} catch (Exception e) {
throw new RuntimeException(e);
}
}
Pros
It is pure java
It can be easily enhanced by adding different headers as a map (instead of passing a null object, like the example above does), authentication, etc.
Handling of protocol switches is supported