Help needed to call a servlet from an applet

Hi,
can someone help me with the way to call a servlet from an applet.
actually on click of a button i wanna call my servlet and save some data in DB.
i am not able to call my servlet. see the sample code which i am trying..
public void actionPerformed(ActionEvent event) {
if (event.getActionCommand().equals("Upload")) {
try {
System.out.println("Upload button has been clicked -----------");
URL url = new URL("http://localhost:8084/uploadApp/TestServlet");
URLConnection urlConnection = url.openConnection();
urlConnection.setDoInput(true);
urlConnection.setDoOutput(true);
urlConnection.setUseCaches(false);
ObjectOutputStream objOut = new ObjectOutputStream (urlConnection.getOutputStream());
objOut.writeBytes(userId); // pass parameter to servlet
objOut.flush();
objOut.close();
} catch (MalformedURLException ex) {
Logger.getLogger(ButtonListener.class.getName()).log(Level.SEVERE, null, ex);
} catch (IOException ex) {
Logger.getLogger(ButtonListener.class.getName()).log(Level.SEVERE, null, ex);
is there any problem with the code? please suggest.

hii,
checkout my add from, HTH
[http://forums.sun.com/thread.jspa?threadID=5419921&messageID=10885709#10885709]
... kopik

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Is there any way to call the servlet from the applet

hi all,
My problem is that i have a applet .After the applet completes execution a servlet should be invoked.Is it possible to do so.
I also want to pass a string array to the servlet.
Is it possible to pass a string array to aservlet.
If yes please do inform me that method.
And from that servlet we should be able to redirect the the response of the applet to the servlet or JSP.
The flow is some what lILE THIS
APPLET TO SERVLET TO SERVLET/JSP

Stop double posting. It won't help
http://forum.java.sun.com/thread.jspa?threadID=642015
and take a look at this.
http://www.google.com/search?hl=en&q=applet+servlet+communication

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hii,
checkout my add from, HTH
[http://forums.sun.com/thread.jspa?threadID=5419921&messageID=10885709#10885709]
... kopik

Calling second servlet from first servlet

I need to call a servlet from a servlet.
I need to call the specific doGet method of servlet 2 from
servlet 1. I also need to return the control to servlet 1
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I did it now by creating a new instance of servlet 2 from servlet1
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request.getRequestDispatcher("path/to/otherServlet").forward(request, response);
or
request.getRequestDispatcher("path/to/otherServlet").include(request, response);will do what you are looking for. See the API documentation on details. Basically the difference is that forward gives FULL control (including that of the headers) to the invoked servlet while include mearly "includes" the results.

A servlet From an applet

Dear friends,
Hope you are doing well.
I am facing a problem of how to call a servlet from an applet.
Any help , please forward it.
thanks
vishal

You can communicate with servlet from an applet, using URL connection, and then send POST/GET methods through HTTP protocol, here is a code snippet,
// applet side, this method will send a POST method to the servlet and then get url openstream to read a
// returned object from the servlet, params should be in the form param1=value&param2=value etc...
public Object getObjectFromServlet(String servletName,String params) {
    Object object = null;
    try {
      URL url = new URL(codeBase,
                        contextRoot + servletName + params);
      URLConnection con = url.openConnection();
      con.setUseCaches(false);
      InputStream in = con.getInputStream();
      ObjectInputStream result = new ObjectInputStream(in);
      object = result.readObject();
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    catch (ClassNotFoundException ex) {
      System.err.println("ClassNotFoundException caught:" + ex.getMessage());
    catch (MalformedURLException ex) {
      System.err.println("MalformedURLException caught:" + ex.getMessage());
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      System.out.println("IOException caught:" + ex.getMessage());
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//servlet side
public void doPost(HttpServletRequest request, HttpServletResponse response){
      //Extract all the necessary supplied parameters from the request object and configurations.
       String param1 = request.getParameter("param1");
       String param2 = request.getParameter("param2");
try {
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Calling a servlet from java

How to call a servlet from java?
your help is greatly appreciated..

Welcome to the forum
You seem to be misunderstanding something. Do some googling to learn what you need about servlets. Simplified, servlets are java code that's hosted by a web container, such as Tomcat. When a servlet gets called as a consequence of someone requesting a url from the container, it takes in a request object and a response object. All the magic is then in creating an appropriate response (e.g. html) for the incoming request.

How can i call a servlet from a servlet ?

Hello,
Can i call a Servlet from within a Servlet ?
and is it "right thing" to Do ?
Thanks

JMO, but I wouldn't do it like this.
Don't have a remote object like a servlet doing database queries for your app. That will mean TWO network hops for every query if the database resides on another machine. The network is the biggest bottleneck you've got.
Write a JavaBean that does the database stuff for you and just have the first servlet instantiate it when it needs it. A Bean has a better chance of being reused, too. Write a TableGateway or DAO for your object.
Or write an EJB to do it.
The only time I've done a servlet-to-servlet connection like that was for one servlet running in a DMZ that would authenticate a user and then forward the request to another servlet running inside the second firewall.
I wouldn't encapsulate database query logic in a servlet like that. JMO - MOD

Call a servlet from Faces Portlet in Websphere

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I am sure about it but you can try this
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Grant:
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AS: BEA WebLogic 8.1.2
DB: Oracle 9i DB 2.0.4
Exception:
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at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java)
at java.io.ObjectInputStream.<init>(ObjectInputStream.java)
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... Desperately seeking knowledge ...

Look at HttpCallout.java in the following code sample
http://www.oracle.com/technology/sample_code/tech/java/jsp/samples/jwcache/Readme.html
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Hi,
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[email protected]

I was wondering is there any way I can call a servlet from jsp? There are two scenarios here
1 - if the jsp is currently being executed/evaluated on the server, then you can use <jsp:include> to "call" a servlet, or <jsp:forward> to cancel the jsp and transfer the control to the servlet.
2 - if the page is already loaded and running in the client, then the only way to call a servlet is making a HTTP request as from any other html page. Jave code does not execute on the client, so you have to use html/javascript at that point.
Calling a servlet within another servlet.
lets say one servlet maintains all dynamic html. I call this servlet from another servlet to create a dynamic page and then insert values into it.Close, but the standard pattern is the reverse of that. What normally happens is you retrieve the values to put in the page, and then call the page, passing in those values. Thats why often you get a servlet/actionbean getting called, which then forwards to a JSP to display the result. The servlet/bean loads all the values required into scope, and then the JSP presents the data.

Question? calling a servlet from EJB.

Can anyone tell me how I would go about calling a servlet
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Application server is Oracle10g.
Thanks.

Welcome to the forum
You seem to be misunderstanding something. Do some googling to learn what you need about servlets. Simplified, servlets are java code that's hosted by a web container, such as Tomcat. When a servlet gets called as a consequence of someone requesting a url from the container, it takes in a request object and a response object. All the magic is then in creating an appropriate response (e.g. html) for the incoming request.

How to call a servlet from another servlet

hi everybody,
i have a problem, i have to call one servlet from another one.
Everything works on my pc, but when i install the application on the customer's server i got an error about an Uknown URL followed by the name of the machine.
Wjat i do is the folloqing :
String urlString = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+"/"+servletName;
URL url = new URL(urlString);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
the variable servletName is the name of the servlet i have to call.
Is there another way to call the servlet ?
All the servlet are installed in the same server.
Any suggestion ?
Cheers.
Stefano

Sweep is correct about requestDispatcher being another approach for inter-servlet delegation; the only issue that i recall with this approach is that it defaults the method of the destination servlet to the one it was called from...for example, calling servlet2 from within servlet1.post() resulted in the dispatcher attempting to utilize servlet2.post() - i believe that i searched for a parameterize solution to no avail :( (ended up handling the request by placing a "fake" doPost() in servlet2 that simply called servlet2.doGet())
however, if your application is functioning correctly on your pc/webserver then the problem may be external to servlet communication (e.g. client webserver's ports not configured or blocked, missing runtime classes, etc.)
my suggestion would be to set aside the programmatic concerns for the moment - what is the response if you open a browser on a client's machine and access the URL in question (i.e. http://clientserver:port/stefanoServlet)? If it will not respond to access in this manner then it certainly won't when your application calls for it.
It's possible that there is a coding error but, given the info supplied, i'd start examining the environment, first. Let us know if you have any luck with the test i recommended or not (please provide abundant detail). Or, if you've found the solution then you may want to post back with a quick blub so the next person knows how to escape the trap.
D

Calling a servlet from a servlet?

Is it possible to call one servlet from another servlet?

You should use servlets to process requests. If what you're asking for is to execute a piece of logic within a servlet before its finished processing the request, then you should consider using a regular java class instead of a servlet. If you just want to send the request information to another servlet you can use getRequestDipatcher().forward(..) method. Keep in mind that by doing so you'll interupt the current servlet.
Regards,
D.

Help needed to call a servlet from an applet

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