I am trying to send two post requests. Both should sent at same time (in my below current code maybe it does one after another) and should wait for maximum 80ms for response, if no response for request, consider response as null.
public void SendRequests(String requestString){
TimeLimiter limiter1 = new SimpleTimeLimiter();
Response response1 = null;
System.out.println("Request Sent to 1");
try{
response1 = limiter1.callWithTimeout(new Callable<Response>() {
public Response call() {
//assume sendPost1 method will send POST request to some server and return response from server
return sendPost1(requestString);
}
}, 80, TimeUnit.MILLISECONDS, true);
}catch(Exception te){
te.printStackTrace();
}
TimeLimiter limiter2 = new SimpleTimeLimiter();
Response response2 = null;
System.out.println("Request Sent to 2");
try{
response2 = limiter2.callWithTimeout(new Callable<Response>() {
public Response call() {
//assume sendPost2 method will send POST request to some server and return response from server
return sendPost2(requestString);
}
}, 80, TimeUnit.MILLISECONDS, true);
}catch(Exception te){
te.printStackTrace();
}
//Do some process using response1 and response2
}
}
I am looking for some ways to send 2 post requests at same time and wait for the 80ms for the response, if no response then consider response as null.
@Gray I tried your solution as per below. First for few minute, my servlet response time is 2ms-10ms, but after that, suddenly, it increases to 200-300ms.
@WebServlet("/incomingTraffic")
public class ServletClass extends HttpServlet {
Gson gson;
private static URL url1;
private static URL url2;
public Exchanger() {
super();
}
public void init(ServletConfig config) throws ServletException {
gson = new Gson();
try{
url1 = new URL( Constants.URL1 );
url2 = new URL( Constants.URL2 );
}catch(Exception e){
}
}
public void destroy() {
}
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.getWriter().append("Served at: ").append(request.getContextPath());
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
ServletInputStream inputStream = request.getInputStream();
Reader reader = new InputStreamReader(inputStream);
//Request class is POJO
final Request requestString = gson.fromJson(reader, Request.class);
reader.close();
//long start = System.currentTimeMillis();
TimeLimiter limiter = new SimpleTimeLimiter();
//Response class is POJO
Response response1 = null;
Response response2 = null;
final ExecutorService threadPool = Executors.newCachedThreadPool();
Future<Response> future1 = threadPool.submit(new Callable<Response>() {
public Response call() {
return sendPost1(requestString);
}
});
Future<Response> future2 = null;
if(Some Condition Satisfy){
future2 = threadPool.submit(new Callable<Response>() {
public Response call() {
return sendPost2(requestString);
}
});
}
threadPool.shutdown();
long start = System.currentTimeMillis();
try {
response1 = future1.get(80, TimeUnit.MILLISECONDS);
} catch (ExecutionException ee) {
// job threw exception
} catch (InterruptedException ie) {
// this (main?) thread was interrupted, good pattern to re-interupt
Thread.currentThread().interrupt();
} catch (TimeoutException te) {
// wait timed out, maybe this is right?
response1 = null;
// try to interrupt the thread
future1.cancel(true);
}
if(requestString.getImp().get(0).getVideo() != null){
// wait for 80 MILLISECONDS minus how long we've been waiting for 2nd request
long end = System.currentTimeMillis();
//System.out.println(start+" - "+end);
long wait = 80 + start - end;
if (wait < 0) {
wait = 0;
}
try {
response2 = future2.get(wait, TimeUnit.MILLISECONDS);
} catch (ExecutionException ee) {
// job threw exception
} catch (InterruptedException ie) {
// this (main?) thread was interrupted, good pattern to re-interrupt
Thread.currentThread().interrupt();
} catch (TimeoutException te) {
// wait timed out, maybe this is right?
response2 = null;
// try to interrupt the thread
future2.cancel(true);
}
}
try {
threadPool.awaitTermination(80, TimeUnit.MILLISECONDS);
} catch (InterruptedException e) {
}
if(response1 == null && response2 == null){
response.setStatus(HttpServletResponse.SC_NO_CONTENT);
}else {
response.setContentType("application/json");
PrintWriter output = response.getWriter();
response.setStatus(HttpServletResponse.SC_OK);
if(Some Condition){
response.getWriter().write(gson.toJson(response1));
}
else{
response.getWriter().write(gson.toJson(response1));
}
}
output.flush();
output.close();
}
}
protected Response sendPost2(Request request){
Response response = null;
String str = gson.toJson(request);
HttpURLConnection conn = null;
try{
conn= (HttpURLConnection) url2.openConnection();
conn.setDoOutput( true );
conn.setInstanceFollowRedirects( false );
conn.setRequestMethod( "POST" );
conn.setRequestProperty( "Content-Type", "application/json");
conn.setRequestProperty("Connection", "keep-alive");
conn.setRequestProperty( "Content-Length", Integer.toString(str.length()));
DataOutputStream wr = new DataOutputStream(conn.getOutputStream());
wr.writeBytes(str);
wr.flush();
wr.close();
int responseCode = conn.getResponseCode();
if(responseCode != 200){
return null;
}
Reader reader = new InputStreamReader(conn.getInputStream());
response = gson.fromJson(reader, Response.class);
conn.disconnect();
}catch(Exception e){
e.printStackTrace();
conn.disconnect();
}
return response;
}
protected Response sendPost1(Request request){
Response response = null;
String str = gson.toJson(request);
HttpURLConnection conn = null;
try{
conn= (HttpURLConnection) url1.openConnection();
conn.setDoOutput( true );
conn.setInstanceFollowRedirects( false );
conn.setRequestMethod( "POST" );
conn.setRequestProperty( "Content-Type", "application/json");
conn.setRequestProperty("Connection", "keep-alive");
conn.setRequestProperty( "Content-Length", Integer.toString(str.length()));
DataOutputStream wr = new DataOutputStream(conn.getOutputStream());
wr.writeBytes(str);
wr.flush();
wr.close();
int responseCode = conn.getResponseCode();
if(responseCode != 200){
return null;
}
Reader reader = new InputStreamReader(conn.getInputStream());
response = gson.fromJson(reader, Response.class);
conn.disconnect();
}catch(Exception e){
e.printStackTrace();
conn.disconnect();
}
return response;
}
}
