EJB Calling a Servlet
Can I make a call to a servlet from within an EJB method ?
If so how ?
Anil
RealPrompt, Inc.
575 Harrison Street, Suite 206
San Francisco, CA 94105
415.546.5600 ext. 204
415.546.0202 fax
510.526.6508 Res.
http://www.realprompt.com
If all else fails, I would suggest using for the page that contains the
applet dynamically gen'd HTML (JSP or servlet or xsl or whatever) and
dynamically encoding an applet parameter that it can pass to the servlet to
figure out which session it is.
Cameron Purdy
[email protected]
http://www.tangosol.com
Consulting Services Available
"Albert Chow" <[email protected]> wrote in message
news:[email protected]...
> Hi Alex,
>
> I'm writing an application which using applet-servlet communication, I
> would like to know how I can pass the session-related information between
an
> applet and a servlet. Thanx in advance.
>
> Albert
>
> "Alex" <[email protected]> wrote in message news:[email protected]...
> > While it is possible by explicitly openning a URL connection,
> > and open and read from an associated stream, this would be at best
> > a hack, in my opinion. If you take this approach, make sure
> > that you take care to send client-side
> > session-related infomation to the servlet (e.g. Cookies ) as well.
> >
> > -Alex
> > "Anil Kumar Kona" <[email protected]> wrote in message
> > news:[email protected]...
> > > we r just doing a sort of proof of concept..
> > > we need to integrate with one of our partner sites.. and they have a
> > servlet
> > > thru which we can connect to their site.. our site is built on EJB..
so
> we
> > r
> > > thinking of two options:
> > > a generic servlet that can make calls to partner servlet
> > > EJB making a call to partner servlet.
> > > so which one do u think is the best way to do ??
> > >
> > > "Kumar Allamraju" <[email protected]> wrote in message
> > > news:[email protected]...
> > > > Never tried it.
> > > > why do you want to do this?
> > > > EJB's are not meant for presentation, they are here to handle
business
> > > > logic.
> > > >
> > > > --
> > > > Kumar
> > > >
> > > >
> > > >
> > > > Anil Kumar Kona wrote:
> > > >
> > > > > Can I make a call to a servlet from within an EJB method ?
> > > > > If so how ?
> > > > >
> > > > > Anil
> > > > >
> > > > > --
> > > > > RealPrompt, Inc.
> > > > > 575 Harrison Street, Suite 206
> > > > > San Francisco, CA 94105
> > > > >
> > > > > 415.546.5600 ext. 204
> > > > > 415.546.0202 fax
> > > > > 510.526.6508 Res.
> > > > > http://www.realprompt.com
> > > >
> > >
> > >
> >
> >
>
>
Similar Messages
-
Best Practice for EJB calls from servlet?
Hi folks
I could not find general rules for making calls to an stateful EJB from the web container (e.g. from a backingBean). In some books they say it is a bad programming style calling them directly from a common servlet. The book says create first an HTTPSession Object and from there call the stateful EJB.
I'm a bit confused because, I'm missing some best practice guide from where to initiate such calls.
Can somebody please point me in the right direction?
Kind Regards
Bruno
Edited by: zajoho on Oct 30, 2008 11:14 PMHi Bruno,
The main issue with the combination of stateful session beans and servlets is the servlet threading model.
It is dangerous to store a stateful session bean reference in servlet instance state, since the servlet instance
can be accessed concurrently, yet a stateful session bean reference is intended to be used by only one
client.
As you point out, one alternative is to store the reference in the HttpSession. That associates the reference
with a particular client, which matches the stateful session bean programming model. -
Question? calling a servlet from EJB.
Can anyone tell me how I would go about calling a servlet
from a session bean thatâs running in the same J2EE application.
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 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 ?
ThanksJMO, 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 -
'Class Cast Exception' while invoking a EJB from a Servlet
Hi,
I am working on J2EE applications.I am using Webgain studio and weblogic server.I
got a problem while invoking EJB from the servlet.
While calling an EJB from the servlet, it is giving that "Class Cast Exception".This
is because, the remote home reference is not able to type casted to the"Home Interface"
of the EJB, even if I type casted explicitly. It is creating the context and able
to identify the EJB with the JNDI name.
Could please help me in solving this problem.I am pasting the code here.
Thanks in advance,
Dharma
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException
resp.setContentType("text/html");
PrintWriter out = new PrintWriter(resp.getOutputStream());
try
Context context=getInitialContext();
Object reference=context.lookup("ArlProjContractorAppletSession");
ArlProjContractorAppletSessionHome home=(ArlProjContractorAppletSessionHome)PortableRemoteObject.narrow(reference,ArlProjContractorAppletSessionHome.class);
//Exception is occuring in the above statement. It is unable
//to cast to the home interface
ArlProjContractorAppletSession the_ejb=null;
try
the_ejb=home.create();
System.out.println("the_ejb = " + the_ejb.toString());
catch(Exception e)
e.printStackTrace();
catch(Exception e)
e.printStackTrace();
// to do: code goes here.
out.println("<HTML>");
out.println("<HEAD><TITLE>Contractor TimeTracker</TITLE></HEAD>");
out.println("<BODY>");
// to do: your HTML goes here.
out.println("</BODY>");
out.println("</HTML>");
out.close();
I came across this kind of problem once. My problem went away after I upgraded
from 5.1 SP6 to 5.1 SP8.
"Dharma" <[email protected]> wrote:
>
>Hi,
>
>I am working on J2EE applications.I am using Webgain studio and weblogic
>server.I
>got a problem while invoking EJB from the servlet.
>
>While calling an EJB from the servlet, it is giving that "Class Cast
>Exception".This
>is because, the remote home reference is not able to type casted to the"Home
>Interface"
>of the EJB, even if I type casted explicitly. It is creating the context
>and able
>to identify the EJB with the JNDI name.
>
>Could please help me in solving this problem.I am pasting the code here.
>
>Thanks in advance,
>Dharma
>
>
>public void doGet(HttpServletRequest req, HttpServletResponse resp)
> throws ServletException, IOException
> {
> resp.setContentType("text/html");
> PrintWriter out = new PrintWriter(resp.getOutputStream());
>
> try
> {
>
> Context context=getInitialContext();
>
> Object reference=context.lookup("ArlProjContractorAppletSession");
>
> ArlProjContractorAppletSessionHome home=(ArlProjContractorAppletSessionHome)PortableRemoteObject.narrow(reference,ArlProjContractorAppletSessionHome.class);
>
>//Exception is occuring in the above statement. It is unable
>//to cast to the home interface
>
> ArlProjContractorAppletSession the_ejb=null;
>
> try
> {
> the_ejb=home.create();
>
> System.out.println("the_ejb = " + the_ejb.toString());
>
> }
> catch(Exception e)
> {
> e.printStackTrace();
> }
> }
> catch(Exception e)
> {
> e.printStackTrace();
> }
> // to do: code goes here.
>
> out.println("<HTML>");
> out.println("<HEAD><TITLE>Contractor TimeTracker</TITLE></HEAD>");
> out.println("<BODY>");
>
> // to do: your HTML goes here.
>
> out.println("</BODY>");
> out.println("</HTML>");
> out.close();
> }
>
>
>
>
>
-
Hi everyone,
I deployed my EJB component in an Oracle 8.1.7 database and I try to access it from a servlet.
If I run my servlet from JDeveloper 3.2 (Web-to-Go), it all works fine. If I run my servlet from JRun 3.01 or from Tomcat 3.2.1, I get the following exception:
javax.naming.NoInitialContextException: Need to specify class name in environmen
t or system property, or as an applet parameter, or in an application resource file: java.naming.factory.initial
at java.lang.Throwable.fillInStackTrace(Native Method)
at java.lang.Throwable.fillInStackTrace(Compiled Code)
at java.lang.Throwable.<init>(Compiled Code)
at java.lang.Exception.<init>(Compiled Code)
at javax.naming.NamingException.<init>(NamingException.java:104)
at javax.naming.NoInitialContextException.<init>(NoInitialContextException.java:58)
at javax.naming.spi.NamingManager.getInitialContext(NamingManager.java:649)
at javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java:242)
at javax.naming.InitialContext.getURLOrDefaultInitCtx(InitialContext.java:279)
at javax.naming.InitialContext.lookup(InitialContext.java:349)
at com.cognicase.framework.base.U0003.AbstractORB.getBean(AbstractORB.java:285)
at com.cognicase.framework.base.U0003.AbstractORB.getBean(Compiled Code)
at com.cognicase.demo.U2007BL.U2007WP_Users.lookupBean(U2007WP_Users.java:60)
at com.cognicase.framework.is.U0103.AbstractBeanWrapper.beforeBeanCall(AbstractBeanWrapper.java:121)
at com.cognicase.demo.U2007BL.U2007WP_Users.valideUser(U2007WP_Users.java:77)
at com.cognicase.demo.U2000WB.U2000MW_WorkSpace.CallEjb(Compiled Code)
at com.cognicase.demo.U2000WB.U2000MW_WorkSpace.doValidateLogin(Compiled Code)
at com.cognicase.demo.U2000WB.U2000MW_WorkSpace.processService(U2000MW_WorkSpace.java:98)
at Demo_0100_01.service(Demo_0100_01.java:128)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.tomcat.core.ServletWrapper.doService(ServletWrapper.java:404)
at org.apache.tomcat.core.Handler.service(Compiled Code)
at org.apache.tomcat.core.ServletWrapper.service(Compiled Code)
at org.apache.tomcat.core.ContextManager.internalService(Compiled Code)
at org.apache.tomcat.core.ContextManager.service(Compiled Code)
at org.apache.tomcat.service.connector.Ajp13ConnectionHandler.processConnection(Compiled Code)
at org.apache.tomcat.service.TcpWorkerThread.runIt(Compiled Code)
at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(Compiled Code)
at java.lang.Thread.run(Compiled Code)
If I add my servlet classes, aurora_client.jar, mts.jar, vbjapp.jar and vbjorb.jar files to the CLASSPATH, it works fine.
The behavior is the same in JRun and Tomcat.
I don't like this solution since I have to make the CLASSPATH point to my application classes at the web server level instead of at the application context level.
Has anyone been able to solve this problem?
Thanks for your help.
nullYes, I did. Actually, if I run my servlet in JDeveloper (Web-to-Go), it all works fine. I also extracted the code that calls the EJB from the servlet and I tested it in a small Java application, and it also works fine.
Things stop to work when I deploy my servlet in JRun or in Tomcat.
It appears that my code is correct, but the environment I try to run it is not, and I can't figure out what's wrong.
Can anyone help me?
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Sandeep Desai ([email protected]):
Have you provided the environmental settings in the servlet.
It should be :
import oracle.aurora.jndi.sess_iiop.ServiceCtx;
env.put(Context.URL_PKG_PREFIXES, "oracle.aurora.jndi");
env.put(Context.SECURITY_PRINCIPAL, username);
env.put(Context.SECURITY_CREDENTIALS, password);
env.put(Context.SECURITY_AUTHENTICATION, ServiceCtx.NON_SSL_LOGIN);
InitialContext ctx = new InitialContext(env);
Object obj = ctx.lookup("test/EJBHome");
HomeObject home = PortableRemoteObject.narrow(
obj,"HomeObject.class");
RemoteObject remote = home.create();
This should make it work!!
<HR></BLOCKQUOTE>
null -
EJB call from one domain to another, authentication problem
Two Weblogic servers. WLS A and WLS B. Different domains. Trust relationship between the domains can't be established.
I have an EJB in WLS B and there is a Web Application deployed to WLS A. There are method-permission declarations in the EJB descriptor xml.
Step 1. User authenticates to Servlet in Web Application (WLS A). Authentication is done with Http Basic Authentication.
Step 2. Servlet makes a JNDI lookup to get a handle to the EJB. Handle can not be fetched with the authentication information which was provided by user to servlet. This means that I need to specify a different username and password, which should be used for authentication at WLS B.
Step 3. After getting a handle to the EJB Servlet calls a method of the EJB.
Everything seems extremely simple. And it should be. But no.
At step 2 servlet propagates authentication information from WLS A to WLS B. This authentication information is valid only inside WLS A, not in WLS B. Result: SecurityException: Invalid Subject.
Setting SECURITY_PRINCIPAL and SECURITY_CREDENTIALS to InitialContext while creating it still results in propagation of authentication information. Same exception.
So I tried something else.
Tthe code doing the JNDI lookups and EJB calls was wrapped inside Security.runAs(new Subject(), ....) -block. Authentication information is no longer propagated to WLS B. So JNDI lookup succeeds, excellent!
But we only got one step further. Now we still need to make the call to EJB method at step 3.
Now that EJB method call results in Security Violation: User: <anonymous> has insufficient permission to access my method.
It's a bit strange, because username and password (for WLS B) were provided for InitialContext while creating it. If the password is invalid, the InitialContext can't be created. So it seems that atleast the username and password ARE checked at WLS B.
Any help and/or suggestions would be highly appreciated.
Here is a misc list of some misc wondering:
-Step 2. Should we make the JNDI lookup to JNDI tree of WLS A instead of WLS B. If we do so, then we should use ejb-ref's at web.xml. This was also quickly tested with no results.
-Would run-as-identity (or some similar element) help? Maybe we could set up some Credential Mapper to WLS A, which would provide username/password when making calls to EJB's of WLS B. Documentation about Credential Mappers seems to be quite useless.There was a time, and it was quite some time ago when something similar was tried and it didn't meet with much success. Sure, it may not have been Domain files, it may have been something more like, say, rocks, but the general principle still applies. If you look at the XML and media parts that make up a Domain file, you can think of those pieces as analogous to the atoms in your average run-of-the-mill rock. Though the atoms in two given average run-of-the-mill rocks may seem quite similar, and cracking them open reveals innards that are almost entirely, but not quite, the same, it's still quite difficult to make one whole rock out of the two.
Now, some say alchemists might be able to accomplish this quite daunting task, but, until a study of use for Domain files (perhaps XMLchemy?) is initiated and studied most earnestly, we shall probably remain unable to bring about the union of one Domain file and another. Or were we talking about the rocks? (You can't melt Domain files, can you? The thought just hit me is all...)
How's that for a long answer? -
How to call a servlet in new window without toolbar from OA page
How to call a servlet in new window without toolbar from a OA page?Please provide sample code
I have tried with the way suggested in Mukul's blog using javascript in Destination URI property.
I tried to open a OA Page and from which forwarded it to a servlet..
It is showing the error:
Error Page
Exception Details.
oracle.apps.fnd.framework.OAException: The application id or shortname () you entered does not exist.
at oracle.apps.fnd.framework.webui.OAPageErrorHandler.prepareException(OAPageErrorHandler.java:1223)
at oracle.apps.fnd.framework.webui.OAPageBean.preparePage(OAPageBean.java:1969)
at oracle.apps.fnd.framework.webui.OAPageBean.preparePage(OAPageBean.java:502)
at oracle.apps.fnd.framework.webui.OAPageBean.preparePage(OAPageBean.java:423)
at oa_html._OA._jspService(_OA.java:86)
at oracle.jsp.runtime.HttpJsp.service(HttpJsp.java:119)
at oracle.jsp.app.JspApplication.dispatchRequest(JspApplication.java:385)
at oracle.jsp.JspServlet.doDispatch(JspServlet.java:259)
at oracle.jsp.JspServlet.internalService(JspServlet.java:178)
at oracle.jsp.JspServlet.service(JspServlet.java:148)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:588)
at oracle.jsp.provider.Jsp20RequestDispatcher.forward(Jsp20RequestDispatcher.java:162)
at oracle.jsp.runtime.OraclePageContext.forward(OraclePageContext.java:175)
at oa_html._OA._jspService(_OA.java:96)
at oracle.jsp.runtime.HttpJsp.service(HttpJsp.java:119)
at oracle.jsp.app.JspApplication.dispatchRequest(JspApplication.java:385)
at oracle.jsp.JspServlet.doDispatch(JspServlet.java:259)
at oracle.jsp.JspServlet.internalService(JspServlet.java:178)
at oracle.jsp.JspServlet.service(JspServlet.java:148)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:588)
at org.apache.jserv.JServConnection.processRequest(JServConnection.java:456)
at org.apache.jserv.JServConnection.run(JServConnection.java:294)
at java.lang.Thread.run(Thread.java:534)
## Detail 0 ##
oracle.apps.fnd.framework.OAException: The application id or shortname () you entered does not exist.
at oracle.apps.fnd.framework.webui.OAWebBeanFactoryImpl.getAppId(OAWebBeanFactoryImpl.java:5391)
at oracle.apps.fnd.framework.webui.OAPageBean.preparePage(OAPageBean.java:969)
at oracle.apps.fnd.framework.webui.OAPageBean.preparePage(OAPageBean.java:502)
at oracle.apps.fnd.framework.webui.OAPageBean.preparePage(OAPageBean.java:423)
at oa_html._OA._jspService(_OA.java:86)
at oracle.jsp.runtime.HttpJsp.service(HttpJsp.java:119)
at oracle.jsp.app.JspApplication.dispatchRequest(JspApplication.java:385)
at oracle.jsp.JspServlet.doDispatch(JspServlet.java:259)
at oracle.jsp.JspServlet.internalService(JspServlet.java:178)
at oracle.jsp.JspServlet.service(JspServlet.java:148)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:588)
at oracle.jsp.provider.Jsp20RequestDispatcher.forward(Jsp20RequestDispatcher.java:162)
at oracle.jsp.runtime.OraclePageContext.forward(OraclePageContext.java:175)
at oa_html._OA._jspService(_OA.java:96)
at oracle.jsp.runtime.HttpJsp.service(HttpJsp.java:119)
at oracle.jsp.app.JspApplication.dispatchRequest(JspApplication.java:385)
at oracle.jsp.JspServlet.doDispatch(JspServlet.java:259)
at oracle.jsp.JspServlet.internalService(JspServlet.java:178)
at oracle.jsp.JspServlet.service(JspServlet.java:148)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:588)
at org.apache.jserv.JServConnection.processRequest(JServConnection.java:456)
at org.apache.jserv.JServConnection.run(JServConnection.java:294)
at java.lang.Thread.run(Thread.java:534)
oracle.apps.fnd.framework.OAException: The application id or shortname () you entered does not exist.
at oracle.apps.fnd.framework.webui.OAWebBeanFactoryImpl.getAppId(OAWebBeanFactoryImpl.java:5391)
at oracle.apps.fnd.framework.webui.OAPageBean.preparePage(OAPageBean.java:969)
at oracle.apps.fnd.framework.webui.OAPageBean.preparePage(OAPageBean.java:502)
at oracle.apps.fnd.framework.webui.OAPageBean.preparePage(OAPageBean.java:423)
at oa_html._OA._jspService(_OA.java:86)
at oracle.jsp.runtime.HttpJsp.service(HttpJsp.java:119)
at oracle.jsp.app.JspApplication.dispatchRequest(JspApplication.java:385)
at oracle.jsp.JspServlet.doDispatch(JspServlet.java:259)
at oracle.jsp.JspServlet.internalService(JspServlet.java:178)
at oracle.jsp.JspServlet.service(JspServlet.java:148)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:588)
at oracle.jsp.provider.Jsp20RequestDispatcher.forward(Jsp20RequestDispatcher.java:162)
at oracle.jsp.runtime.OraclePageContext.forward(OraclePageContext.java:175)
at oa_html._OA._jspService(_OA.java:96)
at oracle.jsp.runtime.HttpJsp.service(HttpJsp.java:119)
at oracle.jsp.app.JspApplication.dispatchRequest(JspApplication.java:385)
at oracle.jsp.JspServlet.doDispatch(JspServlet.java:259)
at oracle.jsp.JspServlet.internalService(JspServlet.java:178)
at oracle.jsp.JspServlet.service(JspServlet.java:148)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:588)
at org.apache.jserv.JServConnection.processRequest(JServConnection.java:456)
at org.apache.jserv.JServConnection.run(JServConnection.java:294)
at java.lang.Thread.run(Thread.java:534) -
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.
StefanoSweep 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 -
I want to send a response from the servlet and then call another servlet.
Hi,
I want to send a response from the servlet and then call another servlet. can this happen. Here is my scenario.
1. Capture all the information from a form including an Email address and submit it to a servlet.
2. Now send a message to the browser that the request will be processed and mailed.
3. Now execute the request and give a mail to the mentioned Email.
Can this be done in any way even by calling another servlet from within a servlet or any other way.
Can any one Please help me out.
Thanks,
RameshMaybe that will help you (This is registration sample):
1.You have Registration.html;
2.You have Registration servlet;
3.You have CheckUser servlet;
4.And last you have Dispatcher between all.
See the code:
Registration.html
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<HTML>
<HEAD>
<TITLE>Hello registration</TITLE>
</HEAD>
<BODY>
<H1>Entry</H1>
<FORM ACTION="helloservlet" METHOD="POST">
<LEFT>
User: <INPUT TYPE="TEXT" NAME="login" SIZE=10><BR>
Password: <INPUT TYPE="PASSWORD" NAME="password" SIZE=10><BR>
<P>
<TABLE CELLSPACING=1>
<TR>
<TH><SMALL>
<INPUT TYPE="SUBMIT" NAME="logon" VALUE="Entry">
</SMALL>
<TH><SMALL>
<INPUT TYPE="SUBMIT" NAME="registration" VALUE="Registration">
</SMALL>
</TABLE>
</LEFT>
</FORM>
<BR>
</BODY>
</HTML>
Dispatcher.java
package mybeans;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.ServletException;
import java.io.IOException;
import javax.servlet.RequestDispatcher;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class Dispatcher extends HttpServlet {
protected void forward(String address, HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
RequestDispatcher dispatcher = getServletContext().
getRequestDispatcher(address);
dispatcher.forward(request, response);
Registration.java
package mybeans;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class Registration extends Dispatcher {
public String getServletInfo() {
return "Registration servlet";
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
ServletContext ctx = getServletContext();
if(request.getParameter("logon") != null) {
this.forward("/CheckUser", request, response);
else if (request.getParameter("registration") != null) {
this.forward("/registration.html", request, response);
CheckUser.java
package mybeans;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.*;
public class CheckUser extends Dispatcher {
Connection conn;
Statement stat;
ResultSet rs;
String cur_UserName;
public static String cur_UserSurname;;
String cur_UserOtchestvo;
public String getServletInfo() {
return "Registration servlet";
public void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
try{
ServletContext ctx = getServletContext();
Class.forName("oracle.jdbc.driver.OracleDriver");
conn = DriverManager.getConnection("jdbc:oracle:oci:@eugenz","SYSTEM", "manager");
stat = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
String queryDB = "SELECT ID, Login, Password FROM TLogon WHERE Login = ? AND Password = ?";
PreparedStatement ps = conn.prepareStatement(queryDB);
User user = new User();
user.setLogin(request.getParameter("login"));
String cur_Login = user.getLogin();
ps.setString(1, cur_Login);
user.setPassword(request.getParameter("password"));
String cur_Password = user.getPassword();
ps.setString(2, cur_Password);
Password = admin");
rs = ps.executeQuery();
String sn = "Zatoka";
String n = "Eugen";
String queryPeople = "SELECT ID, Surname FROM People WHERE ID = ?";
PreparedStatement psPeople = conn.prepareStatement(queryPeople);
if(rs.next()) {
int logonID = rs.getInt("ID");
psPeople.setInt(1, logonID);
rs = psPeople.executeQuery();
rs.next();
user.setSurname(rs.getString("Surname"));
FROM TLogon, People WHERE TLogon.ID = People.ID";
ctx.setAttribute("user", user);
this.forward("/successLogin.jsp", request, response);
this.forward("/registration.html", request, response);
catch(Exception exception) {
}CheckUser.java maybe incorrect, but it's not serious, because see the principe (conception).
Main is Dispatcher.java. This class is dispatcher between all servlets. -
Calling a servlet in java class
Hello,
I try to call a servlet from java class
but is dose not work
what should be the problem
public void callServlet()
try
// xxservlet is the servlet name
URL url = new URL("http://www.mydomain.com/xxservlet");
URLConnection hpCon = url.openConnection();
hpCon.setDoOutput(true);
OutputStreamWriter out = new OutputStreamWriter(hpCon.getOutputStream());
out.write("This Is a Test");
out.flush();
out.close();
}catch(Exception ex){ex.printStackTrace();}
// My Servlet is in package servlets
public class XXServlet extends HttpServlet
public void service(HttpServletRequest req, HttpServletResponse resp) {
try {
ServletInputStream sin = req.getInputStream();
int len = req.getContentLength();
byte[] input = new byte[len];
ServletInputStream sin = req.getInputStream();
int c, count = 0 ;
while ((c = sin.read(input, count, input.length-count)) != -1) {
count +=c;
sin.close();
String inString = new String(input);
System.out.println("Servlet is running ...."+inString);
} catch (IOException e) {
try{
resp.setStatus(HttpServletResponse.SC_BAD_REQUEST);
resp.getWriter().print(e.getMessage());
resp.getWriter().close();
} catch (IOException ioe) {
// web.xml
<servlet>
<servlet-name>xxservlet</servlet-name>
<servlet-class>servlets.XXServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>xxservlet</servlet-name>
<url-pattern>/xxservlet</url-pattern>
</servlet-mapping>
}regards
Edited by: the_Orient on Mar 30, 2009 3:16 AMI have start servlet from brwoser only to test that servlet works fine
A gain what I need
I want to call a servlet from a javs class
URL url = new URL("http://www.mydomain.com/myservlet");
URLConnection hpCon = url.openConnection();
hpCon.setDoOutput(true);
OutputStreamWriter out = new OutputStreamWriter(hpCon.getOutputStream());
out.write("Hello Woprld");
out.flush();
out.close();// Servlet
public void doGet(HttpServletRequest req, HttpServletResponse resp) {
try {
String xp =req.getSession().getServletContext().getRealPath("/");
File f = new File(xp+"/students/info.txt");
f.createNewFile();
} catch (IOException e) {
try{
resp.setStatus(HttpServletResponse.SC_BAD_REQUEST);
resp.getWriter().print(e.getMessage());
resp.getWriter().close();
} catch (IOException ioe) {
problem file can not be created
public void doPost(HttpServletRequest req, HttpServletResponse resp)
}I hope that is clear -
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 -
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. -
Calling a servlet from another servlet?
Hi
I would like to know that how can I call one Servlet from another Servlet. I have tried getServlet() method of ServletContext but it has been deprecated. I want to call a specific method of the other Servlet, is there any other way?
ThanksI should have seen it from your previous post :(
Code of Servlet 1:
public void doGet(HttpServletRequest request,
HttpServletResponse response) throws
ServletException, IOException
RequestDispatcher rDispatch = null ;
rDispatch = getServletConfig
().getServletContext().getRequestDispatcher
("/Servlet2") ;
rDispatch.forward(request, response) ;
System.out.println("Back in 1");
I assume Servlets 1and 2 are in same web app and you've mapped your servlet2 to /Servlet2 in your web.xml
make it as
rDispatch = request.getRequestDispatcher("/Servlet2");
rDispatch.forward(request,response);
Nothin's wrong with yer servlet2 -
Has anyone successfully called a servlet from xsql? If you have, have you called one from the href in the xsl:stylesheet?
nullCan you post a sample of what you're trying to do? Not sure what you mean by having the XSQL "call a servlet"? Call a servlet when? to serve/use what?
Are you trying to using a servlet to return a dynamically-constructed stylesheet in the role of:
<?xml-stylesheet type="text/xsl" href="http://foo/servlets/myservlet"?>
If not, can you expound on what you're trying to achieve/accomplish?
Thanks.
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