Multiple servlet requests

Hi,
I want to send multiple requests to my servlet (tomcat container) simultaneously from Java code........what is the best way of doing this in Java?? Thread?? If so how do I do this??
Can anyone suggest please..........
Help will be much appreciate.....Many Thanks..

Does that mean that I would create a new thread and in the run() method
make an HTTP request...I have NOT used threads a lot in Java hence....
I just want to simulate firing requests quickly in Java code instead of JMeter which is quite a big product
Threads are what you would use to achieve multiple
concurrent requests, but if you want a testing tool,
use something like JMeter.
http://jakarta.apache.org/jmeter/

Similar Messages

Servlets handle multiple, concurrent requests

Hi, folks. Could someone give me a basic idea of how Servlets handle multiple, concurrent requests which are sent from user's web browser, or possibly, point me some useful web links, tutorials. Let me take a example to make sure that i have explained the question clearly: let's say there is a website that does air ticket booking service. Suppose there is a spare seat exists for a particular flight. There are two users logon to the website and they are both looking for this particular seat. So, once these user's HTML form requests are sent to server, how do i implement my servlet to handle these requests properly, in another words, make sure this seat is only allowed booked by a single user. thanks in advance.

This acturally raises me a another question which i
still have some uncertainties. In another assignment i
did last semester, that was we had multiple users
using our database and accessing, retirving and
updating database by using jdbc. And what i did was
let every user call a particular method within a
javabean for setting up database connection, then goes
for the specific that needs to be dealt with. So, what
i am wondering now is that can i possibly having a
different approach, like setting up only a single
connection(ie. a public Connection objec) which being
exist all the time so that all request can get
connection by calling this object's relevant method.
Hope i explained it clearly.
If I understand you correctly, then you would have to make the methods of this Connecting Object synchronized so that there was only ever one connection to the database at any one time.
If a database is transactional, that means it has attempted to deal with the problem of multiple connections and statements being executed at the same time on the same data. If you have one single Connecting Object then you don't have to worry about transactions, but you do need to make sure that there aren't multiple threads running, each trying to use your Connecting Object.
The synchronized keyword makes sure only one thread can use the synchronized method at any one time.

Invoking multiple servlets from a single request

Hi. I'm wondering if it's possible to execute multiple servlets within a single request and context. I have a servlet defined in web.xml which says:
<servlet>
<servlet-name>firstServlet</servlet-name>
<servlet-class>mypackage.First</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>firstServlet</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>
(clearly this one gets invoked upon every request in the context)
But I also have another servlet which gets invoked when another condition applies:
<servlet>
<servlet-name>secondServlet</servlet-name>
<servlet-class>mypackage.Second</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>secondServlet</servlet-name>
<url-pattern>*.ftl</url-pattern>
</servlet-mapping>
So if the url was http://localhost:8080/mycontext/page.ftl, I want both servlets to get executed. Is there anyway I can do this? I've tried the above code and it doesn't work. How would I do this (or can I even do it)?
Thanks,
Dylan

depending on what your servlets do, you might also think of using filters. say you have a first servlet that compresses the respone you would be better off to implement this as a filter. than you might have a second serlvet that does request logging stuff. this might also be better than in a filter, so you chain first and second filter. the business logic is put in servlet three i.e.

How to use my connection pool in multiple servlets?

I now have a functioning connection pool using these lines in a servlet:
private Connection getConnection(String lookup) throws NamingException, SQLException {
Context context = new InitialContext();
DataSource ds = (DataSource)context.lookup(lookup);
Connection ocon = ds.getConnection();
context.close();
return ocon;
} // private Connection getConnection(String lookup) throws NamingException, SQLException {
========================
If I want to create additional servlets in the same web app which query the same database,
do I need to repeat this block of code in every servlet, or can I just put it in one servlet
and have other servlets access it in some way to get a connection? Should I change the code
above from a "private" Connection to a "public" Connection?
An example servlet is shown below. To put my question another way: If I want to
create a second servlet with a different set of queries, would I just make a copy of the first
servlet and then change only the queries, or is there a more efficient way to have multiple
servlets get connections from the pool?
Any suggestions are greatly appreciated.
Thank you.
Logan
************************************servlet example**********************************
package CraigsClasses;
import javax.servlet.*;
import javax.servlet.jsp.*;
import java.net.*;
import java.util.*;
import java.io.*;
import javax.servlet.http.*;
import java.sql.*;
import java.util.Date;
import java.text.*;
import javax.naming.*;
import javax.sql.DataSource;
public class CraigsMain extends HttpServlet {
public void init(ServletConfig config) throws ServletException {
super.init(config);
private Connection getConnection(String lookup) throws NamingException, SQLException {
Context context = new InitialContext();
DataSource ds = (DataSource)context.lookup(lookup);
Connection ocon = ds.getConnection();
context.close();
return ocon;
} // private Connection getConnection(String lookup) throws NamingException, SQLException {
// Process the http Get request
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
try {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
String sql = "select formtitle from checkboxforms where cbformid = 157";
// error occurs at this line
Connection ocon = getConnection("java:comp/env/jdbc/CraigsList");
PreparedStatement pStmt = ocon.prepareStatement(sql);
ResultSet rs1 = pStmt.executeQuery();
rs1.next();
out.println("<br>" + rs1.getString(1));
rs1.close();
pStmt.close();
ocon.close();
} catch(SQLException sqle) {
System.err.println("sql exception error: " + sqle);
} catch(NamingException ne) {
System.err.println("naming exception error: " + ne);
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
=======================================================================

sjasja, Thank you for the reply. What you are suggesting is exactly what I have been looking for. But I'm pretty weak on how to make this separate con pool servlet work. My first attempt is shown below. It doesn't compile this line, which is obviously wrong:
public static Connection getConnection(String lookup) throws NamingException, SQLException {
Could you please help me with this servlet code? Thanks.
package CraigsClasses;
import javax.servlet.*;
import javax.servlet.jsp.*;
import java.net.*;
import java.io.*;
import javax.servlet.http.*;
import java.sql.*;
import javax.naming.*;
import javax.sql.DataSource;
public class ConPoolInit extends HttpServlet {
public void init(ServletConfig config) throws ServletException {
super.init(config);
try {
public static Connection getConnection(String lookup) throws NamingException, SQLException {
Context context = new InitialContext();
DataSource ds = (DataSource)context.lookup(lookup);
Connection ocon = ds.getConnection();
context.close();
return ocon;
} // private Connection getConnection(String lookup) throws NamingException, SQLException {
} catch(SQLException sqle) {
System.err.println("sql exception error: " + sqle);
} catch(NamingException ne) {
System.err.println("naming exception error: " + ne);
=======================================

Multiple post requests using a single HttpConnection

Hi,
is it possible to send multiple post requests using a single Http connection.
i am currently trying to simulate the preformance overhead because of creating HttpURLConnection to talk to my servlet. But, that made me wonder, if is there a way to send multiple post requests using a single HttpURLConnection.
can anyone help me with this.
thanks in advance

Hi
I found this article through Google. I hope it helps a little
http://www.developer.com/tech/article.php/761521
D

Problem with running multiple servlet in same webapplication with tomcat 3

Hi all,
I am using Tomcat 3.0 as webserver with jdk1.3, Servlet 2.0,
Templates for html file and oracle 8i on UNIX platform.
I have problem with multiple servlet running same webapplication.
There are two servlet used in my application. 1) GenServlet.class
and 2) ServletForPrinting.class
All of my pages go through GenServlet.class which reads some property files
and add header and footer in all pages.
I want reports without header & footer that is not possible through GenServlet in my application.
So I have used another servlet called ServletForPrinting --- just for reading html file.
It is as follow:
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class ServletForPrinting extends HttpServlet {
public void service (HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException
// set content-type header before accessing the Writer
response.setContentType("text/html");
PrintWriter out = response.getWriter();
File f1 = null;
String report = null;
String path = request.getPathInfo();
try{
String p = "/var/home/latif/proj/webapps/WEB-INF/classes" + path;
System.out.println(p);
f1 = new File(p);
p = null;
if (f1.exists()) {
FileReader fr = new FileReader(f1);
BufferedReader br = new BufferedReader(fr);
report = new String();
while ((report = br.readLine()) != null) {
out.println(report);
}catch(Exception e) {
out.close();
report = null;
path = null;
f1 = null;
} // end class
It works fine and display report properly.
But now Problem is that if report is refreshed many times subsequently,
WebServer will not take any new change in any of java file used in web-application.
It works with the previous class only and not with updated one.
Then I need to touch it. As soon as I touch it, webserver will take updated class file.
Anybody has any idea regarding these situation?
Is there any bug in my ServletForPrinting.java ?
Any solution ????? Please suggest me.
Suggestion from all are invited. That will help me a lot.
Thanks in advance
Deepalee.

Llisas wrote:
I solved the problem, I just had to wire the blocks in a sequential way (I still don't know why, but it works).
Feel free to delete this topic.
I would strongly suggest at least reading this tutorial to give you an idea of why your fix worked (or maybe only appeared to work). Myself, I never just throw up my hands and say, "Whatever," and wash my hands of the situation without trying my best to understand just what fixed it. Guranteed you'll run into the same/similar problem and this time your fix won't work.
Please do yourself a favor and try to understand why it is working now, and save yourself (or more likely, the next poor dev to work on this project) some heartache.
Bill
(Mid-Level minion.)
My support system ensures that I don't look totally incompetent.
Proud to say that I've progressed beyond knowing just enough to be dangerous. I now know enough to know that I have no clue about anything at all.

Multiple POST requests

Greetings everybody,
For this particular question I am not getting any help from the Java forums and Google.
Not very long ago I had to send a stream of bytes from an applet to a servlet (the applet and its helper classes are packed inside a signed jar file), but I used to fail miserably at every step.
I tried every trick in the book (for me the books were Google and Java forums!!). I set the servlet's path in the Windows CLASSPATH, I tried to call the applet from within a servlet- of course after placing the applet file in the servlets folder- (in the hope that since the applet was in the same location as the servlets the URL would get established) e.t.c but still URL url=new URL(<servlet URL>) refused to invoke the servlet.
Finally somehow I managed to get it done using the code below:
public class Xyz extends Applet
//DONT BE SURPRISED RIGHT NOW!!
Class cls=this.getClass();
ClassLoader cldr=cls.getClassLoader();
//THE ACTUAL SERVLET CONNECTING CODE
URL url=cldr.getResource("http://localhost:8000/servlet/<SomeServlet>");
/*This statement does not work........ URL url=new URL("http://localhost:8000/servlet/<SomeServlet>").A NULL URL OBJECT GETS CREATED!! */
HttpURLConnection hurlc=(HttpURLConnection)url.getConnection();
//ALL THE NECESSARY FORMALITIES TO BE PERFORMED TO WRITE THE STREAM TO THE SERVLET
hurlc.setDoInput(false);
hurlc.setDoOutput(true);
hurlc.setUseCaches(false);
hurlc.setRequestMethod("POST");
OutputStream os=hurlc.getOutputStream();
//WRITING THE STREAM
os.write(<some byte buffer>);
//NOW COMES THE TRICKY PART
hurlc.getResponseCode();
I had to do getResponseCode() because once ClassLoader.getResource(<servlet URL>) invoked the servlet using the GET method I COULD NOT INVOKE THE SERVLET AGAIN. I had to force an invokation using getResponseCode().
Well all is well now excepting for a small irritant. Instead of issuing one POST request the URLConnection is issuing multiple POST requests. In the Apache logs I get to see something like:
GET /snodx/callapplet.htm 200 116
GET /snodx/keystore_for_holding_fingerprint_for_trusted_applet 200 234
GET /snodx/applet_and_helpers.jar 200 105
HEAD /servlet/<SomeServlet> 200 187
POST /servlet/<SomeServlet> 200 312
POST /servlet/<SomeServlet> 500 604
POST /servlet/<SomeServlet> 500 604
The last 2 lines indicate that the servlet was invoked but the connection closed somehow. This is confirmed by taking a look at the Apache error logs:
Premature end of script headers.
Premature end of script headers.
In the JServ servlet engine error logs I am getting:
(500)apj12 returned an error handling request
cannot scan servlet headers.
The problem is occurring somewhere in getResponseCode().This statement is invoking the servlet using the request method set (POST) several times (2 or 3 times).
Can someone explain what's going on?
This is briefly the servlet code:
public class SomeServlet extends HttpServlet
//THE SERVICE METHOD IS CALLED BY A HEAD REQUEST TO THIS SERVLET
public void service(ServletRequest reque,ServletResponse respon) throws ServletException,IOException
this.doPost((HttpServletResponse)reque,(HttpServletResponse)respon);
//GO DIRECTLY TO THE POST METHOD
public void doPost(HttpServletRequest req,HttpServletResponse resp) throws ServletException,IOException
ServletInputStream sis=req.getInputStream();
if(sis.available()<2) //CHECK THAT THERE IS STREAM WHICH HAS AT LEAST 2 BYTES OF DATA!!
log("NO STREAM FROM APPLET");
else
//PERFORM ALL ACTIONS TO WRITE TO STREAM OF BYTES TO A LOCAL FILE
I have the servlet engine JServ 1.1.2 configured to run with Apache 1.3.19 on Windows 2000.
I compiled the Applet and the Servlet using JDK1.3 and JSDK2.0. I have JRE 1.3.1_02 installed on my Win2k machine.
Sorry for the long winded story here.
Awaiting a reply.
SNODX
(The search keywords combination getResponseCode multiple POST requests +Applet and many other related keyword combinations did not match any document in the Java forums. The search string "Multiple POST requests" "getResponseCode" and many other related search strings did not match any document in Google.I am continuing the search effort however

interresting the classloader solution. Well if that works, i would keep it like that so far.
But maybe this can help:
os.write(<some byte buffer>);
..and then
os.flush()//to make sure the outputstream is sent immediatly.
//i think getResponseCode() is not necsessary in that case
//but not certain, after all ...setUseCaches(false);
One thing you should do is remove the complete
service() {
...this.doPost();
the reason is that when a POST arrives at the servlet, the default service-method of the ancestor class (which is javax.servlet.Servlet) will automaticaly make a call to doPost() of the javax.servlet.http.HttpServlet subclass. You should not overide it I believe.
maybe... -try to establish an OutputStream only once in the Applet.
- receive the other end exactly once (as you did) in the doPost as an InputStream;
- eventually wrap both sides in respective Buffered(In)(Out)putStream(Reader)(Writer)
- start looping and .write() and .read() at both sides on the single and same in-and-outputStream();
(i.e avoid establishing the connection from the applet several times..., get one connection and keep it)
sorry if this story would be irrelevant,
Papyrus

Limit of Weblogic for servlet requests

          Hi,
          Could someone tell me what is the limit on the number of servlet requests per
          second a weblogic server
          can handle.. We are facing some performance issue.. Would like to know the limit
          that WLS server can process
          at a time.
          Thanks in advance,
          rgds, rams


Thanks Robert - I had the same results on 4-way E420 (and slightly less for
          session-less JSP). Don't you think it can be potentially useful to have some
          'baseline' results to be available for some most popular hardware/JVM configurations ?
          (Of course, these numbers have nothing to do with an actual application performance, but
          they are useful in establishing the 'upper limit' - something like HelloWorld servlet,
          HelloWorld JSP with session=false, HelloWorld JSP with sessions enabled).
          Robert Patrick <[email protected]> wrote:
          > Hmm... This is a loaded question. It comes down to what type of hardware is the
          > server running on, what is the servlet doing, what does your network look like, and
          > on and on. I can tell you that with a version of WLS 5.1, I was able to get approx.
          > 1100 to 1200 "page views per second" from a HelloWorld servlet running on a 4-way
          > Sun E420 using Mercury's LoadRunner software running on multiple NT machines. For
          > this hardware configuration and server version, I would use this as the upper limit
          > for a single instance...
          > Rams wrote:
          >> Hi,
          >>
          >> Could someone tell me what is the limit on the number of servlet requests per
          >> second a weblogic server
          >> can handle.. We are facing some performance issue.. Would like to know the limit
          >> that WLS server can process
          >> at a time.
          >>
          >> Thanks in advance,
          >>
          >> rgds, rams
          Dimitri

Is it possible to have Multiple Spool requests in one batch job overview?

Hi,
While running one of my z program in back ground, there are two spools generated (one by write statement and one by OPEN_FORM statement and both the spools are available in SP01 Transaction), but when i see the job overview in transaction SM37, I only see one spool request (that of the last spool request). Can any body in the group please tell me is it possible to see multiple spool requests in the job overview of one Abap program and if yes, how?
Thank you.
Abinash

Hi Jayanthi,
Thank you for the link. But probably that discussion was also an unsolved one.
Anyway, does any one in the group think that display of multiple spools per one step job is dependent on client / SAP Server setting? Because as evident from the chain of mails in the link provided by Jayanthi, some people say that they see multiple spool requests for one program in batch mode job overview (SM37)? If yes, can some body tell me the required configuration?

How to create the multiple spool requests for a single report.

Hi gurus,
I have one requirement to be completed , i need to send the out put of the report via mail in pdf format. for that what i did was, iam executing report in background and creating spool request and converting it to pdf and sending the file.
now the problem is, its a customer ledger report, for each customer i need to create a new spool request and send mail to that particular customer, now my dought is how to create multiple spool requests for a single pro and how i need to go about it.
And one more question is can we create a spool request for a report which is running in online.
waiting for inputs frm gurus.

Hello,
As per my knowledge for creating new spool id you will have to set
output_options-tdnewid = 'X'.
and then using
job_output_info-spoolids
create a pdf using
call function 'CONVERT_OTFSPOOLJOB_2_PDF'
Rachana.

Multiple leave requests on the same day

We would like to enforce a check so that multiple leave requests of the same type cannot be submitted for the same day on ESS.
How can this be achieved ? We are on EP 7.0 and ECC 6.0 and are using webdynpro java version of the ESS applications.
Any configuration available for this or does this require a BADI implementation ?
Thanks in advance.
Thank You,
Raj

http://wiki.sdn.sap.com/wiki/display/ERPHCM/ValidationsforESSLeaverequest
read here, it requies a badi implementation only, no config is available!
You have to call backend exits from the badi of leave request
Edited by: Siddharth Rajora on Aug 2, 2011 7:48 AM

How to post multiple http requests using a single http connection in java

I am using the httpurlconnection class and it allows only to post one request on a connection. I require to post multiple http requests by opening a single connection. Code examples please. Thanx in advance.

Hi
I found this article through Google. I hope it helps a little
http://www.developer.com/tech/article.php/761521
D

Printing multiple spool requests at a time

Hi All,
I am using function module RSPO_OUTPUT_SPOOL_REQUEST to print the contents of the spool request. I want to print multiple spool requests at a time. We can input only one spool request number to the above function module at a time. Is there any way that I can print multiple spool requests with only single Print Popup Window ?
Thanks.

Hi Khanna,
I tried that option at first place only. It results in multiple Print Popups. I want to avoid this. For all spool print requests, I want to show ONLY ONE Print Popup.
Thanks.

How to find multiple transport requests for one object

Hi all,
Is there any function module which will fetches multiple transport requests ( if created ) for one object.I tried almost all the function modules , but i didn't got the solution.
I need to develop a report ,   which will takes a single Task number as input and gets the Request number from table E070.
Based on that Request Number i will fetch remaining Task numbers under it.
Then for all the Tasks Numbers, i am fetching their objects by using table E071.
I need to list out whether any of these objects are in multiple Transport Requests. Once i got all the Transport Request numbers i need to release the Request based on their Transport Request sequence.
I tried the following FM's , but not able to get the solution.
SVRS_DISPLAY_VERSION_LIST
SVRS_GET_VERSION_DIRECTORY_46
SVRS_GATHER_REQUEST_FRAGS
Thanks..

Hello
I have tried with below code
DATA list_tab TYPE TABLE OF abaplist.
SUBMIT RSWBO040 USING SELECTION-SET 'TEST'
                EXPORTING LIST TO MEMORY
               AND RETURN.
CALL FUNCTION 'LIST_FROM_MEMORY'
   TABLES
     listobject = list_tab
   EXCEPTIONS
     not_found = 1
     OTHERS           = 2.
IF sy-subrc = 0.
   CALL FUNCTION 'WRITE_LIST'
     TABLES
       listobject = list_tab.
ENDIF.
break-point.
Submitting the program(RSWBO040) of SE03 transaction a will result in 'CNTL_ERROR' dump.
Please try some other options
Thanks

CHaRM-Is that possible to create multiple Transport Request in UC

HI Gurus,
Quick question on ur.gent correction using Solution Manager CHaRM in EHP1. Is it possible to create multiple transport request(TR) for single ur.gent correction (UC). DO NOT confuse with transport task.
For example, after I created transport request and developer start working and release the task, realised to add another transport request for same UC. When I tried, it did not create any TR but checked the message found that
Schedule Manager: Monitor
Job Status: Processing completed, but with warnings
Program Name: /TMWFLOW/SCMA_TRORDER_CREATE
Action to be checked: Ur.gent Correction: Create Transport Request
There is already an open request, XXXXXXXXXX, for this project
So only way I can do that I released the TR and able to create another TR.
May be wondering why I need to create another TR, why not create TASK and work on that.
But this is the requirement at our company.
I will appreciate the effort and time to provide me the solution of this.
Thanks
Ava

Hi Ragu,
That's really quick turn around. Unfortunately not able to found whatever you mentioned in your message. Here is detail,
I navigate to Actions - Depending on Status, found the entry as
Trans. Type     StatProf         UserStatus     Seq     Action in SAP Change Manager
SDHF             SDHFHEAD   E0002            10       CREATE_HF
SDHF             SDHFHEAD   E0002            20       CREATE_REQ
SDHF             SDHFHEAD   E0002            30       SAVE_PARTNER
SDHF             SDHFHEAD   E0002            40       SET BO LINKS
Where SDHF - Ur.gent Correction
           E0002 - In Development
           CREATE_HF -        Create an Instance in SAP Change Manager
           CREATE_REQ -     Create Transport Request with Task
           SAVE_PARTNER - Save Partners in Respective Partner Roles
           SET BO LINKS -     Sets Links to Business Objects
I don't see any OPEN_TR.
Any other place need to make change.
Thanks
Ava

Multiple servlet requests

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