How to call a servlet from Java code

Question

I want to call servlet with some parameters and receive a response. The code is written in Java. What is the best (cleanest) way to do that?

Also, can i call a servlet and continue with the code withoud waiting the servlet to finish (close the connection and "forget about it")?

You can spin off your request into a separate `Thread` if you want to continue with other parts of your application. See also: http://stackoverflow.com/questions/4349854/calling-a-servlet-from-a-java-application — Catchwa, May 03 '11 at 07:13
"What is the best (cleanest) way to do that" what does *best* or *cleanest* mean. — Raedwald, Jul 28 '14 at 12:28

score 4 · Answer 1 · answered May 03 '11 at 07:12

Example from here:

import java.net.*;
import java.io.*;

public class URLConnectionReader {
  public static void main(String[] args) throws Exception {
    URL yahoo = new URL("http://www.yahoo.com/");
    URLConnection yc = yahoo.openConnection();
    BufferedReader in = new BufferedReader(
                            new InputStreamReader(
                            yc.getInputStream()));
    String inputLine;

    while ((inputLine = in.readLine()) != null) 
        System.out.println(inputLine);
    in.close();
  }
}

From your perspective, servlet is just an URL on some server. As for not waiting for a response - read about Java threads. But you cannot close the HTTP connection without waiting for a servlet to finish as this might cause a servlet to fail. Simply wait for the response in a separate thread and discard it if it doesn't matter.

Do i have to wait for a response (if the solution if to use a thread, than the answer is still yes - i have to wait for an answer). What about passing parameters to the servlet? do i have to bild the url by myself (using '?' and '&') or there is a cleaner way? — Erik Sapir, May 03 '11 at 07:14

score 4 · Accepted Answer · answered May 03 '11 at 07:26

Better use Apache HttpClient API for handling and communication with servlet

http://hc.apache.org/httpcomponents-client-ga/index.html

Features:

Param are easy to pass and parse response.
It allows even communicating thru Proxy
Open source
It also support Asyncronous and many more Please refer the above url.

score 2 · Answer 3 · answered May 03 '11 at 07:40

2

You could use Apache HttpClient Apache HttpClient

This also has Non-blocking I/O functionality available NIO extensions

Here's a Tutorial for the Apache HttpComponents.

You could also try Jetty or Async Http Client

answered May 03 '11 at 07:40

Jon

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i really dislike people who downvote with no comment. Here's an upvote to balance the force. – Nico Jun 01 '12 at 15:41

score 0 · Answer 4 · answered Aug 14 '14 at 08:51

0

For me this was the shortest and most useful tutorial about Apache HttpClient.

answered Aug 14 '14 at 08:51

Gismo Ranas

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How to call a servlet from Java code

4 Answers4