DO we really use Servlet Filters in realtime applications where?
DO we really use Servlet Filters in realtime applications where?
Can any one give me somegood exampleor link where i can find required information.
Regards
Vijendra
Yes people do use Servlet Filters in real applications. The most common usage is as a common entry point for security checks or for logging purposes.
One thing you could do is search the forum for questions on filters. Often the poster has a problem that he believes can be solved using filters.
If you want to learn how to develop filters check the Sun J2EE tutorial.
Similar Messages
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Using servlet filters- to read the rsponse
Hi ,
In my web application i am displaying the final result as an xml in a jsp.Now what ever I am displaying to the user i want to get that as a string and store it in a database.
For this i think i have to get that from the response object, i just looking at the servlet filters , but i am not sure using the servlet filters is a good option or not.
And i am really not sure exactly how to use the filters.
Please somene help me with this , is there a way for this,Please let me know if you don't understand what i am trying to do, so that i explain in little more detail.Not exact but close. Describes a filter that caches the response to disc:
http://www.onjava.com/pub/a/onjava/2003/11/19/filters.html?page=3 -
How to use servlets in portal web application in Weblogic Portal 4.0
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Will Servlet Filters affect performance
Hi,
is it true that Servlet Filters will have impact on Web application performance by slowing things? any suggestion plz..
Regards,
A.The question "Will X affect performance" is almost always bogus.
It only makes sense to compare the performance of two code bases that perform a certain predetermined task. In your case, you could make your question not be bogus by comparing an application that uses servlet filters with another application that performs the same functions in a different way. You don't seem to be prepared to do that. -
Error in Oracle 10g (10.0.3) in Servlet Filtering
Hi
I found this error on oracle 10g (10.0.3) Version. my same code is working on 9.0.4 can you please tell what is the problem? I am using servlet filtering.
Mine is swing base application which will call applet and this will call Servlet.
500 Internal Server Error
java.lang.IllegalStateException: dispatcher chain is empty
at com.evermind[Oracle Application Server Containers for J2EE 10g (10.0.3.0.0) - Developer Preview].server.http.EvermindHttpServletRequest.getCurrentDispatcher(EvermindHttpServletRequest.java:3975)
at com.evermind[Oracle Application Server Containers for J2EE 10g (10.0.3.0.0) - Developer Preview].server.http.EvermindHttpServletRequest.getParameters(EvermindHttpServletRequest.java:1393)
at com.evermind[Oracle Application Server Containers for J2EE 10g (10.0.3.0.0) - Developer Preview].server.http.EvermindHttpServletRequest.getParameter(EvermindHttpServletRequest.java:2126)
at com.fmr.cfit.security.IdentityAgent.getUserIdFromParameter(Unknown Source)
at com.fmr.cfit.security.IdentityAgent.getUserId(Unknown Source)
at com.fmr.cfit.security.IdentityAgent.doFilter(Unknown Source)
at com.evermind[Oracle Application Server Containers for J2EE 10g (10.0.3.0.0) - Developer Preview].server.http.FileRequestDispatcher.handleWithFilter(FileRequestDispatcher.java:130)
at com.evermind[Oracle Application Server Containers for J2EE 10g (10.0.3.0.0) - Developer Preview].server.http.FileRequestDispatcher.forwardInternal(FileRequestDispatcher.java:210)
at com.evermind[Oracle Application Server Containers for J2EE 10g (10.0.3.0.0) - Developer Preview].server.http.HttpRequestHandler.processRequest(HttpRequestHandler.java:824)
at com.evermind[Oracle Application Server Containers for J2EE 10g (10.0.3.0.0) - Developer Preview].server.http.HttpRequestHandler.run(HttpRequestHandler.java:270)
at com.evermind[Oracle Application Server Containers for J2EE 10g (10.0.3.0.0) - Developer Preview].server.http.HttpRequestHandler.run(HttpRequestHandler.java:112)
at com.evermind[Oracle Application Server Containers for J2EE 10g (10.0.3.0.0) - Developer Preview].util.ReleasableResourcePooledExecutor$MyWorker.run(ReleasableResourcePooledExecutor.java:291)
at java.lang.Thread.run(Unknown Source)I am able to resolve the issue:
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-Yatan -
JSF page goes blank when using with servlet filters...
Hi there,
I have a JSF page, which shows up fine (in both IE and Firefox) in normal scenarios.
But as soon as I apply servlet filters onto the faces extension, I get into trouble. So after setting up the filters, when I load the same page(s) in each of the browsers, the filters run fine in the background, but the page comes up blank (in both IE and FF).
Happening only with JSF / Faces pages.
Once I removed the filter mapping, the page loads up just fine.
Would appreciate any feedback on this. TIA!More info on the original post...
Platforms:
Tomcat 5.5.15
JSF/Faces - Sun RI 1.2
Servlet Spec: 2.4
Portion of the Web.xml code (after applying the filters onto the faces components):
<listener>
<listener-class>
com.sun.faces.config.ConfigureListener
</listener-class>
</listener>
<servlet>
<servlet-name>Faces Servlet</servlet-name>
<servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>Faces Servlet</servlet-name>
<url-pattern>*.faces</url-pattern>
</servlet-mapping>
<filter>
<filter-name>PreProcessFilter</filter-name>
<filter-class>.....view.util.PreProcessFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>PreProcessFilter</filter-name>
<url-pattern>*.html</url-pattern>
</filter-mapping>
<filter-mapping>
<filter-name>PreProcessFilter</filter-name>
<url-pattern>*.jsp</url-pattern>
</filter-mapping>
<filter-mapping>
<filter-name>PreProcessFilter</filter-name>
<url-pattern>*.faces</url-pattern>
</filter-mapping> Thanks for your time! -
Using servlet in combination with public_html subfolders
Hi,
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What I'm building now is a servlet filter that will check if the user already has a session. If the user doesn't have one the user should be redirected to a login page. Getting this logic to work hasn't been the problem. My problem started when I wanted to place .jsp files in a subfolder.
First of all, I wasn't able to create a subfolder from JDev 10.1.3 so I had to this through the file system (added a subfolder in the public_html folder).
Then when I tried to implement the filter I had a hard time getting the jsp pages and the servlets to work together. This is my setup:
I have a loginservlet that handles the login post request and sets the session if all is ok.
I have both the welcome.jsp and login.jsp in a subfolder called "app".
Then I have a servlet filter.
When trying to access the welcome.jsp the filter succesfully redirects the request to the login.jsp. But from here things go wrong. First, the login page has problems retrieving the css stylesheet. And when it submits the form it doesn't seem to process correctly since it doesn't move on to the welcome.jsp.
Can someone point in the direction of some sort of guide on how to incorporate subfolders for jsp pages in combination with servlets? And is creating subfolders in any way possible from JDeveloper?
Message was edited by:
DeddiekoelWhat kind of URL do you use to access the css files etc. from your jsp? Your URL needs to follow the directory structure, so you may need e.g. "../css/style.css"
Also make sure all your files are imported into jdev, since files that aren't won't be copied into the server instance. -
Since switching to IMAP and using message filters, I often get duplicate messages in my local folders. I think this is a bug.
That is my guess as to what is happening.
When the IMAP part starts syncing with the server to fill in the inbox, the message filter system starts working before it is done syncing. I appears that the filters runs too quickly because as the filter moves a msg to a local folder, the sync thread think it need to download it again from the server. If the sync with the remote server takes a long time, I could end up with 5 or more copies of the exact same email.
This has always happened for years now but I figured someone would have noticed it and fix it by now. Now I am wondering it it has something to do with my filters or my settings.
Has anyone run into this before?Toys,
I was just doing a search to see if anyone else was feeling this way! I am also at a university and I don't really like see thousands of unread messages in mail. (Fortunately, with Leopard you can select the dock icon to show only the messages in your inbox but I still don't like having the public folder in there).
Please let me know if you find out anything and I will do the same for you. If I have time later I am going to run by our IT office later and ask them. -
Servlet filters work with OC4J 9.0.2, but not JDeveloper 9.0.2
I spent a day or so last week building a servlet filter and testing it in OC4J 9.0.2. It works fine. I didn't bother loading it into JDeveloper because there weren't any complicated debugging issues.
I just tried loading it into JDeveloper 9.0.2 this morning, and I discovered that even though OC4J 9.0.2 has no problem with servlet filters, apparently JDeveloper 9.0.2 does. It complains about validation of the "web.xml", saying that "filter" is not a valid element of "web-app". I was specifying the 2.3 dtd.
Is this a problem that I can easily work around in JDeveloper 9.0.2?
If I load the JDeveloper 9.0.3 developer preview, can I get it to use 9.0.2 for its embedded OC4J, and not produce any new problems?For JDev 9.0.2, this issue is documented in the release notes at
http://otn.oracle.com/products/jdev/htdocs/readme_902.html#vmoption -
Can't write file on server using Servlet
Dear programers,
I have written a little method that creates a simple file. This method works fine when I execute it on my PC but it doesn't work when the servlet execute it.
For example:
public void test(){
FileOutputStream fileHTML = null;
String html_file_name = "\\\\MyServer\\dir\\filename.html";
try{
//create new HTML file
fileHTML = new FileOutputStream(html_file_name);
String text = "Hello World";
fileHTML.write(text.getBytes());
fileHTML.close();
}catch(IOException ex){
System.err.println(e.getMessage()+ " Cann't create new HTML file!");
I don't get any exception, it seems that the file is written to the server but it doesn't.
What can be the problem?a) You do mean Servlet not Applet don't you? Applets aren't allowed access to the file system. If it's an applet open the "java console" window on the browser. You'll probably see a security exception.
b) If it's really a servlet any errors are likely to turn up on the server's log files. Check those. You file path doesn't contain a drive letter so maybe the drive letter is wrong in the servlet environment.
c) Always use Writers to output text, not Streams. That's not the source of your problem but it make for much messier code. -
Urgent : Problem with Servlet Filters in Weblogic6.1
Hi,
We have developed an application using Tomcat4.1.24 with Weblogic6.1 Service Pack2.
Now we are removing the Tomcat and moving the web layer into weblogic. We have implemented Servlet Filters and Listeners.
When I converted .jar and .war files into .ear file and deployed into Weblogic6.1. But that application is not deploying. I found that Weblogic6.1 does not support Filters and Listeners from Servlet2.3.
When I tried to deploy in the Weblogic6.1, it is giving the error as " java.lang.reflect.UndeclaredThrowableException".
Could somebody please give me a solution how my filters and listeners can make working with weblogic6.1.
Is there any solution.. My application is successfully working with Weblogic8.1. But I want the solution in weblogic6.1. It would be great if somebody can give me solution how to make Filters n Listeners working with Weblogic6.1.
Thanks in advance.Hi Prasanna,
Thank you for the timely reply.
I have already done according to the process given in the url which u have given me.
set and getFilterConfig methods are implemented in my AuthenticationFilter class. But still I could not be able deploy the application and I am not able to get the ServletContext object from Session. When I tried commenting the Filters and Listeners in my web.xml file then my .ear file was successfully deployed but I could not get the ServletContext from Session.
Below code is from my web.xml:
<filter>
<filter-name>HRSuthenticationFilter</filter-name>
<filter-class>com.peramb.hrs.servlet.AuthenticationFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>HRSAuthenticationFilter</filter-name>
<url-pattern>/jsp/*</url-pattern>
</filter-mapping>
<filter-mapping>
<filter-name>HRSAuthenticationFilter</filter-name>
<servlet-name>action</servlet-name>
</filter-mapping>
<listener>
<listener-class>com.peramb.hrs.servlet.HRSContextListener</listener-class>
</listener>
When I comment the above code from web.xml it is deploying with out errors.. but I am not getting the servlet context, hence my application is not working.
When tried uncommenting the listerns part or Filters part or bothe, My application is deploying with an error on the console. I.e,
“<Sep 22, 2005 12:20:36 PM IST> <Error> <Management> <Error deploying application
.\config\mydomain\applications\hrsgb.ear: java.lang.reflect.UndeclaredThrowable
Exception>â€.
And the error in Weblogic logs is below:
####<Sep 22, 2005 12:20:36 PM IST> <Info> <HTTP> <spacker> <myserver> <ExecuteThread: '0' for queue: '__weblogic_admin_html_queue'> <system> <> <101047> <[WebAppServletContext(6387482,hrsgb,/hrsgb)] registering JSPServlet with initArgs '[JspConfig: verbose=true,packagePrefix=jsp_servlet,-compiler=javac,compileFlags=,workingDir=E:\bea\wlserver6.1\config\mydomain\applications\.wlnotdelete\wlap36546\WEB-INF\_tmp_war_mydomain_myserver_hrsgb,pageCheckSeconds=1,superclass=weblogic.servlet.jsp.JspBase,keepgenerated=false,precompileContinue=false,compilerSupportsEncoding=true,encoding=null,defaultfilename=index.jsp,compilerclass=null,noTryBlocks=false]'>
####<Sep 22, 2005 12:20:36 PM IST> <Debug> <HTTP> < spacker > <myserver> <ExecuteThread: '0' for queue: '__weblogic_admin_html_queue'> <system> <> <101158> <Exception thrown while loading hrsgb: java.lang.SecurityException: sealing violation>
java.lang.SecurityException: sealing violation
at java.net.URLClassLoader.defineClass(URLClassLoader.java:229)
at java.net.URLClassLoader.access$100(URLClassLoader.java:51)
at java.net.URLClassLoader$1.run(URLClassLoader.java:190)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:183)
at java.lang.ClassLoader.loadClass(ClassLoader.java:294)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:281)
at java.lang.ClassLoader.loadClass(ClassLoader.java:250)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:310)
at weblogic.servlet.internal.WebAppServletContext.registerEventListener(WebAppServletContext.java:2031)
at weblogic.servlet.internal.WebAppServletContext.initFromDescriptors(WebAppServletContext.java:1471)
at weblogic.servlet.internal.WebAppServletContext.init(WebAppServletContext.java:943)
at weblogic.servlet.internal.WebAppServletContext.<init>(WebAppServletContext.java:878)
at weblogic.servlet.internal.HttpServer.loadWebApp(HttpServer.java:515)
at weblogic.j2ee.WebAppComponent.deploy(WebAppComponent.java:77)
at weblogic.j2ee.Application.addComponent(Application.java:176)
at weblogic.j2ee.J2EEService.addDeployment(J2EEService.java:117)
at weblogic.management.mbeans.custom.DeploymentTarget.addDeployment(DeploymentTarget.java:364)
at weblogic.management.mbeans.custom.DeploymentTarget.addDeployment(DeploymentTarget.java:150)
at weblogic.management.mbeans.custom.WebServer.addWebDeployment(WebServer.java:76)
at java.lang.reflect.Method.invoke(Native Method)
at weblogic.management.internal.DynamicMBeanImpl.invokeLocally(DynamicMBeanImpl.java:636)
at weblogic.management.internal.DynamicMBeanImpl.invoke(DynamicMBeanImpl.java:621)
at weblogic.management.internal.ConfigurationMBeanImpl.invoke(ConfigurationMBeanImpl.java:374)
at com.sun.management.jmx.MBeanServerImpl.invoke(MBeanServerImpl.java:1557)
at com.sun.management.jmx.MBeanServerImpl.invoke(MBeanServerImpl.java:1525)
at weblogic.management.internal.MBeanProxy.invoke(MBeanProxy.java:468)
at weblogic.management.internal.MBeanProxy.invoke(MBeanProxy.java:209)
at $Proxy37.addWebDeployment(Unknown Source)
at weblogic.management.configuration.WebServerMBean_CachingStub.addWebDeployment(WebServerMBean_CachingStub.java:1337)
at weblogic.management.mbeans.custom.DeploymentTarget.addDeployment(DeploymentTarget.java:350)
at weblogic.management.mbeans.custom.DeploymentTarget.addDeployment(DeploymentTarget.java:150)
at java.lang.reflect.Method.invoke(Native Method)
at weblogic.management.internal.DynamicMBeanImpl.invokeLocally(DynamicMBeanImpl.java:636)
at weblogic.management.internal.DynamicMBeanImpl.invoke(DynamicMBeanImpl.java:621)
at weblogic.management.internal.ConfigurationMBeanImpl.invoke(ConfigurationMBeanImpl.java:374)
at com.sun.management.jmx.MBeanServerImpl.invoke(MBeanServerImpl.java:1557)
at com.sun.management.jmx.MBeanServerImpl.invoke(MBeanServerImpl.java:1525)
at weblogic.management.internal.ConfigurationMBeanImpl.updateConfigMBeans(ConfigurationMBeanImpl.java:507)
at weblogic.management.internal.ConfigurationMBeanImpl.invoke(ConfigurationMBeanImpl.java:376)
at com.sun.management.jmx.MBeanServerImpl.invoke(MBeanServerImpl.java:1557)
at com.sun.management.jmx.MBeanServerImpl.invoke(MBeanServerImpl.java:1525)
at weblogic.management.internal.DynamicMBeanImpl.addDeployment(DynamicMBeanImpl.java:997)
at weblogic.management.internal.DynamicMBeanImpl.addDeployment(DynamicMBeanImpl.java:984)
at weblogic.management.internal.DynamicMBeanImpl.add(DynamicMBeanImpl.java:969)
at weblogic.management.internal.DynamicMBeanImpl.invokeLocally(DynamicMBeanImpl.java:648)
at weblogic.management.internal.DynamicMBeanImpl.invoke(DynamicMBeanImpl.java:621)
at weblogic.management.internal.ConfigurationMBeanImpl.invoke(ConfigurationMBeanImpl.java:374)
at com.sun.management.jmx.MBeanServerImpl.invoke(MBeanServerImpl.java:1557)
at com.sun.management.jmx.MBeanServerImpl.invoke(MBeanServerImpl.java:1525)
at weblogic.management.internal.MBeanProxy.invoke(MBeanProxy.java:468)
at weblogic.management.internal.MBeanProxy.invoke(MBeanProxy.java:209)
at $Proxy88.addTarget(Unknown Source)
at weblogic.management.mbeans.custom.ApplicationManager.autoDeploy(ApplicationManager.java:930)
at weblogic.management.mbeans.custom.ApplicationManager.addApplication(ApplicationManager.java:1039)
at weblogic.management.mbeans.custom.ApplicationManager.addApplication(ApplicationManager.java:954)
at weblogic.management.mbeans.custom.ApplicationManager.poll(ApplicationManager.java:851)
at weblogic.management.mbeans.custom.ApplicationManager.poll(ApplicationManager.java:781)
at weblogic.management.mbeans.custom.ApplicationManager.update(ApplicationManager.java:210)
at java.lang.reflect.Method.invoke(Native Method)
at weblogic.management.internal.DynamicMBeanImpl.invokeLocally(DynamicMBeanImpl.java:636)
at weblogic.management.internal.DynamicMBeanImpl.invoke(DynamicMBeanImpl.java:621)
at weblogic.management.internal.ConfigurationMBeanImpl.invoke(ConfigurationMBeanImpl.java:374)
at com.sun.management.jmx.MBeanServerImpl.invoke(MBeanServerImpl.java:1557)
at com.sun.management.jmx.MBeanServerImpl.invoke(MBeanServerImpl.java:1525)
at weblogic.management.internal.MBeanProxy.invoke(MBeanProxy.java:468)
at weblogic.management.internal.MBeanProxy.invoke(MBeanProxy.java:209)
at $Proxy5.update(Unknown Source)
at weblogic.management.console.webapp._domain.__upload_app._jspService(__upload_app.java:150)
at weblogic.servlet.jsp.JspBase.service(JspBase.java:27)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:262)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:198)
at weblogic.servlet.internal.RequestDispatcherImpl.forward(RequestDispatcherImpl.java:284)
at weblogic.servlet.jsp.PageContextImpl.forward(PageContextImpl.java:119)
at weblogic.management.console.actions.ForwardAction.perform(ForwardAction.java:35)
at weblogic.management.console.actions.internal.ActionServlet.doAction(ActionServlet.java:171)
at weblogic.management.console.actions.internal.ActionServlet.doPost(ActionServlet.java:85)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:616)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:262)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:198)
at weblogic.servlet.internal.WebAppServletContext.invokeServlet(WebAppServletContext.java:2678)
at weblogic.servlet.internal.ServletRequestImpl.execute(ServletRequestImpl.java:2412)
at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:140)
at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:121)
####<Sep 22, 2005 12:20:36 PM IST> <Error> <J2EE> < spacker> <myserver> <ExecuteThread: '0' for queue: '__weblogic_admin_html_queue'> <system> <> <160001> <Error deploying application hrsgb: Could not load hrsgb>
####<Sep 22, 2005 12:20:36 PM IST> <Error> <Management> < spacker> <myserver> <ExecuteThread: '0' for queue: '__weblogic_admin_html_queue'> <system> <> <141042> <Error deploying application .\config\mydomain\applications\hrsgb.ear: java.lang.reflect.UndeclaredThrowableException>
I could not trace the problem. Please help me with some solution for the above problem -
How to display "All Items" using a "Filtered Rows" Combo Box
Hi
How do I make a Combo Box with "Filtered Rows" show "All Values" by default, AND have the option to select individual filters?
If my data was
North
South
East
West
I would want the Combo box to display
ALL
North
South
East
West
When the user selected:
North, they should see just the filtered rows with North
South, they should see just the filtered rows with South
ALL should be the default, and it should ifilter/include North, Soutn, East and West (i.e. showing all the rows)
I need to use a Combo box and Filtered Rows, because I actually want to filter my dataset using multiple columns:
Company, Region, District, Sector, Value
My current method is to:
use a Combo to filter the RawData on Company into an Intermediate_Company worksheet
use another Combo to filter the Intermediate_Company worksheet on Region into an Intermediate_Region worksheet
use another Combo to filter the Intermediate_Region worksheet on District into an Intermediate_District worksheet
use another Combo to filter the Intermediate_District worksheet on Sector into an Intermediate_Sector worksheet
then display in a List View from the Intermediate_Sector worksheet.
Any comments on this method would also be welcome.
Thanks for your help
StuartThanks Muwa
I've uploaded a non-working version here: http://www.teradepot.com/ntxgoo6629zi/Simple_All_Combo.xlf.html
I've figured out how to use tthe filter to copy a subset of the rows in the source date to the destination are of the worksheet.
I can't figure out how to use a filter to copy ALL the rows in the source to the destination.
I've seen hints about using hidden filters, but I can't make this work, either. It's quite depressing, really
I'm very grateful for any help you can give.
Thanks in advance
Stuart -
When to use servlets / when applets
hi there,
building a web application when do I use servlet technology and when applets? What are the arguments to let me choose between them? Or combine both servlets and applets? Any ideas/URLs are welcome.
greetingsis it a matter how powerful my servermachine is?
No, not really, but an applet will use the processor on the client and the servlet will use the server's cpu, so that could potentially be an issue for you.
or a matter of security or whatever?
There are security issues with Applets, as they cannot access system resources, but neither can Servlets, so I think that's a non issue.
What exactly do you need to do with the data once you get it out of the database? THAT is the real question! If you want to fetch data and then display the data as text or HTML in a browser, use a servlet. If you need the client to interact with the data in a more sophisticated way, use an Applet. With an Applet, you can put buttons and sliders and whatever and control things, and interact with the application. But a Servlet is not an application, nor is it interactive. A Servlet is called, it gets parameters from an HTTP client, and then it responds, and it's done. An Applet has runtime, and stays running, to interact with the client indefinitely.
I'll give you a real world example. With a Servlet, you might output a web page to a browser, and show an advertisement somewhere on the page. However, an Applet could show an advertisement, and update that ad every few seconds or so, and show one after another, like a slideshow. Even better, an Applet could go get a BRAND NEW ad that was just put in the database and get the new ad at runtime, showing up to the minute results. An Applet could do a stock ticker program, Servlet cannot. Get the difference? -
When to Use Servlet only, EJB only and, both Servlet And EJB???
I have a question, If I want to build a Web application. Sometime i found that there is no need to use EJB as Servlet already provide that functionality.
Can anyone tell me when do I use Pure Servlet? When do I use Pure EJB and, When do I use Both EJB and Servlet???
I am very interesting in it.
Thanks.
JackEJB and servlets are two different things. Trying to compare them doesn't really make sense. A web application is always going to need some way to process Http requests and this in Java is done accomplished through Servlets (or jsp pages which in turn also use servlets).
EJBs are the basis of distributed cross-platform objects. They are handled through name services and stored in databases. An Entity Bean can be "brought back to life" as long as it's info is stored in a database. Regardless of a server being restarted. All this database support behind an Entity Bean (transactions, queries etc.) are very transparent to the programmer. They are provided by the EJB vendor.
The class properties of a Servlet (or class-level member variables) are shared among all requests (running thread instances of the service method). That's why they should be used with a lot of caution. This feature can be very useful but if used improperly can also be very vulnerable to security and synchronization issues.
I'm not an EJB expert but this explanation should give you some idea of what EJBs are all about. -
IPlanet 6.0 And servlet filters with filter-test.war not working
Hi, I am trying to get servlet filters running on iPlanet6.0. I deployed the 'filter-test.war' file, and then modified web-apps.xml to contain the filter configuration. I even modified the example classes to log to a file on disk. The only thing that happens is intialization. Further it never get's to call the 'doFilter' method at all.
Is there anything I'm missing?
All I did was deploy the war file, and then modify the web-apps.xml file, and then restart the server. Is there anything else?
Here is my web-apps.xml file as been modified.
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE vs PUBLIC "-//Sun Microsystems, Inc.; iPlanet//DTD Virtual Server Web Applications 6.0//EN"
"http://developer.iplanet.com/webserver/dtds/iws-webapps_6_0.dtd">
<vs>
<web-app uri="/" enable="true"/>
<web-app uri="/filter-test" dir="C:/temp/iplanet/deployed" enable="true">
<!-- Define servlet-mapped and path-mapped example filters -->
<filter>
<filter-name>Servlet Mapped Filter</filter-name>
<filter-class>filters.ExampleFilter</filter-class>
<init-param>
<param-name>attribute</param-name>
<param-value>filters.ExampleFilter.SERVLET_MAPPED</param-value>
</init-param>
</filter>
<filter>
<filter-name>Path Mapped Filter</filter-name>
<filter-class>filters.ExampleFilter</filter-class>
<init-param>
<param-name>attribute</param-name>
<param-value>filters.ExampleFilter.PATH_MAPPED</param-value>
</init-param>
</filter>
<filter>
<filter-name>Request Dumper Filter</filter-name>
<filter-class>filters.RequestDumperFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>Servlet Mapped Filter</filter-name>
<servlet-name>invoker</servlet-name>
</filter-mapping>
<filter-mapping>
<filter-name>Path Mapped Filter</filter-name>
<url-pattern>/servlet/*</url-pattern>
</filter-mapping>
<filter-mapping>
<filter-name>Request Dumper Filter</filter-name>
<url-pattern>/servlet/*</url-pattern>
</filter-mapping>
</web-app>
</vs>
Thank youWhy not try WS 6.1 -- which has the full support for Servlet 2.3 including filters.
As for 6.0, what URI do you use? Is it:
/filter-test/servlet/<servlet-name>
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