RequestDispatcher example issue
Hi,
I am trying and reading as below (http://www.javatpoint.com/requestdispatcher-in-servlet)
I did not understand what it mean by
I downloaded eclipse source code as zip. How to import as web project. When i import as attached (Existing Project into workspace) creating as java project.(can i convert java project to web after creation?). When i run on the project since it is java project i am not seeing --->RunAs-->Run on server option.
when i import as web war file and when i click--> Browse button that is not showing the downloaded zip. How to solve this issue.
I opened command prompt--cd
C:\Users\Desktop\gpfolder\
then i executed below command
==> jar -cvf requestdispatcher.war *
that generated war
I imported that war. But i see generated web project structure is not correct where src came under WebConent instead of JAvaResource-->src.
How to fix this and import properly.
>>> out.print("Sorry UserName or Password Error!");
does aboe line prints in the page or on the console. I thought console similar to System.out.println in java.
I even searched for .classpath file by click Control Shift R then opened classpath file and change the servlet.jar reference wrongly location from D drive to my local Servlet.jar location(C:\softwares\apac
please advise
Any links resources ideas highly appreciated. Thanks in advance
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I am trying and reading as below (http://www.javatpoint.com/requestdispatcher-in-servlet)
Introduction to Servlet
What is Servlet Servlet Terminology Servlet API Servlet Interface GenericServlet HttpServlet Servlet Life Cycle Servlet Example How servlet works? War File welcome-file-list Load on startup
Servlet with IDE
servlet in Eclipse servlet in Myeclipse servlet in Netbeans
ServletRequest
Servlet Collaboration
RequestDispacher sendRedirect
ServletConfig
ServletContext
Attribute in Servlet
Session Tracking
Session Techniques 1) Cookies in Servlet Cookies: Login & Logout 2) Hidden Form Field 3) URL Rewriting 4) HttpSession Session: Login & Logout
Event and Listener
Servlet Filter
What is Filter Authentication Filter FilterConfig Useful examples
Servlet Miscellaneous
ServletInputStream ServletOutputStream Annotation Servlet SingleThreadModel SSI
Development
Registration Example Fetching records Improving Performance Uploading file Downloading file Servlet Sending Email Write data to PDF Login Example Writing Image
Servlet Quiz
Servlet Quiz(Part-1) Servlet Quiz(Part-2) Servlet Quiz(Part-3)
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RequestDispatcher in Servlet
RequestDispatcher Interface
Methods of RequestDispatcher interface
forward method
include method
How to get the object of RequestDispatcher
Example of RequestDispatcher interface
The RequestDispacher interface provides the facility of dispatching the request to another resource it may be html, servlet or jsp.This interface can also be used to include the content of antoher resource also. It is one of the way of servlet collaboration.
There are two methods defined in the RequestDispatcher interface.
Methods of RequestDispatcher interface
The RequestDispatcher interface provides two methods. They are:
public void forward(ServletRequest request,ServletResponse response)throws ServletException,java.io.IOException :Forwards a request from a servlet to another resource (servlet, JSP file, or HTML file) on the server.
public void include(ServletRequest request,ServletResponse response)throws ServletException,java.io.IOException :Includes the content of a resource (servlet, JSP page, or HTML file) in the response.
forward() method of RequestDispatcher interface
As you see in the above figure, response of second servlet is sent to the client. Response of the first servlet is not displayed to the user.
include() method of RequestDispatcher interface
As you can see in the above figure, response of second servlet is included in the response of the first servlet that is being sent to the client.
How to get the object of RequestDispatcher
The getRequestDispatcher() method of ServletRequest interface returns the object of RequestDispatcher. Syntax:
Syntax of getRequestDispatcher method
public RequestDispatcher getRequestDispatcher(String resource);
Example of using getRequestDispatcher method
RequestDispatcher rd=request.getRequestDispatcher("ser vlet2");
//servlet2 is the url-pattern of the second servlet
rd.forward(request, response);//method may be include or forward
Example of RequestDispatcher interface
In this example, we are validating the password entered by the user. If password is servlet, it will forward the request to the WelcomeServlet, otherwise will show an error message: sorry username or password error!. In this program, we are cheking for hardcoded information. But you can check it to the database also that we will see in the development chapter. In this example, we have created following files:
index.html file: for getting input from the user.
Login.java file: a servlet class for processing the response. If password is servet, it will forward the request to the welcome servlet.
WelcomeServlet.java file: a servlet class for displaying the welcome message.
web.xml file: a deployment descriptor file that contains the information about the ser
I did not understand what it mean by
If password is servlet, it will forward the request to the WelcomeServlet, otherwise will show an error message: sorry username or password error!
I downloaded eclipse source code as zip. How to import as web project. When i import as attached (Existing Project into workspace) creating as java project.(can i convert java project to web after creation?). When i run on the project since it is java project i am not seeing --->RunAs-->Run on server option.
when i import as web war file and when i click--> Browse button that is not showing the downloaded zip. How to solve this issue.
I opened command prompt--cd
C:\Users\Desktop\gpfolder\
then i executed below command
==> jar -cvf requestdispatcher.war *
that generated war
I imported that war. But i see generated web project structure is not correct where src came under WebConent instead of JAvaResource-->src.
How to fix this and import properly.
>>> out.print("Sorry UserName or Password Error!");
does aboe line prints in the page or on the console. I thought console similar to System.out.println in java.
I even searched for .classpath file by click Control Shift R then opened classpath file and change the servlet.jar reference wrongly location from D drive to my local Servlet.jar location(C:\softwares\apac
please advise
Any links resources ideas highly appreciated. Thanks in advance
Import0.jpg
Import.jpg
Import2.jpg
Import3.jpg
Import4.jpg
SOLUTION
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ASKER
when i run as tomcat 6 giving error
The server does not support version 3.0 of the J2EE Web module specification.
The server does not support version 3.0 of the J2EE Web module specification.
ASKER
when i try to change 2.5 dynamic project not taking. please advise
ASKER CERTIFIED SOLUTION
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ASKER
when i try to change 2.5 dynamic project not allowing. says cannot change dyncamic project version to 2.5. please advise
ASKER
Is this example running when imported as java project from downloaded zip and converting to dynamic webproject and run on tomcat 7 server.
i still get error
please advise
i still get error
HTTP Status 500 - Simple : Unsupported major.minor version 51.0 (unable to load class Simple)
type Exception report
message Simple : Unsupported major.minor version 51.0 (unable to load class Simple)
description The server encountered an internal error that prevented it from fulfilling this request.
exception
java.lang.UnsupportedClassVersionErr or: Simple : Unsupported major.minor version 51.0 (unable to load class Simple)
org.apache.catalina.loader.WebappCla ssLoader.f indClassIn ternal(Web appClassLo ader.java: 2899)
org.apache.catalina.loader.WebappCla ssLoader.f indClass(W ebappClass Loader.jav a:1173)
org.apache.catalina.loader.WebappCla ssLoader.l oadClass(W ebappClass Loader.jav a:1681)
org.apache.catalina.loader.WebappCla ssLoader.l oadClass(W ebappClass Loader.jav a:1559)
org.apache.catalina.authenticator.Au thenticato rBase.invo ke(Authent icatorBase .java:491)
org.apache.catalina.valves.ErrorRepo rtValve.in voke(Error ReportValv e.java:99)
org.apache.catalina.valves.AccessLog Valve.invo ke(AccessL ogValve.ja va:953)
org.apache.catalina.connector.Coyote Adapter.se rvice(Coyo teAdapter. java:408)
org.apache.coyote.http11.AbstractHtt p11Process or.process (AbstractH ttp11Proce ssor.java: 1023)
org.apache.coyote.AbstractProtocol$A bstractCon nectionHan dler.proce ss(Abstrac tProtocol. java:589)
org.apache.tomcat.util.net.JIoEndpoi nt$SocketP rocessor.r un(JIoEndp oint.java: 312)
java.util.concurrent.ThreadPoolExecu tor$Worker .runTask(T hreadPoolE xecutor.ja va:886)
java.util.concurrent.ThreadPoolExecu tor$Worker .run(Threa dPoolExecu tor.java:9 08)
java.lang.Thread.run(Thread.java:662 )
note The full stack trace of the root cause is available in the Apache Tomcat/7.0.42 logs.
please advise
ASKER
web.xml looks as below
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>Simple</servlet-name>
<servlet-class>Simple</servlet-class >
</servlet>
<servlet>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>WelcomeServlet</servle t-name>
<servlet-class>WelcomeServlet</servl et-class>
</servlet>
<servlet-mapping>
<servlet-name>Simple</servlet-name>
<url-pattern>/go</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>WelcomeServlet</servle t-name>
<url-pattern>/welcome</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>login.html</welcome-fi le>
</welcome-file-list>
</web-app>
ASKER
i change the ajva back to 1.6 as attached i am getting different error now(https://www.java.net/node/664117) please advise
type Exception report
message Error instantiating servlet class Simple
description The server encountered an internal error that prevented it from fulfilling this request.
exception
javax.servlet.ServletExcep
org.apache.catalina.authen
org.apache.catalina.valves
org.apache.catalina.valves
org.apache.catalina.connec
org.apache.coyote.http11.A
org.apache.coyote.Abstract
org.apache.tomcat.util.net
java.util.concurrent.Threa
java.util.concurrent.Threa
java.lang.Thread.run(Threa
root cause
java.lang.ClassNotFoundExc
org.apache.catalina.loader
org.apache.catalina.loader
org.apache.catalina.authen
org.apache.catalina.valves
org.apache.catalina.valves
org.apache.catalina.connec
org.apache.coyote.http11.A
org.apache.coyote.Abstract
org.apache.tomcat.util.net
java.util.concurrent.Threa
java.util.concurrent.Threa
java.lang.Thread.run(Threa
note The full stack trace of the root cause is available in the Apache Tomcat/7.0.42 logs.
java6.jpg
type Exception report
message Error instantiating servlet class Simple
description The server encountered an internal error that prevented it from fulfilling this request.
exception
javax.servlet.ServletExcep
org.apache.catalina.authen
org.apache.catalina.valves
org.apache.catalina.valves
org.apache.catalina.connec
org.apache.coyote.http11.A
org.apache.coyote.Abstract
org.apache.tomcat.util.net
java.util.concurrent.Threa
java.util.concurrent.Threa
java.lang.Thread.run(Threa
root cause
java.lang.ClassNotFoundExc
org.apache.catalina.loader
org.apache.catalina.loader
org.apache.catalina.authen
org.apache.catalina.valves
org.apache.catalina.valves
org.apache.catalina.connec
org.apache.coyote.http11.A
org.apache.coyote.Abstract
org.apache.tomcat.util.net
java.util.concurrent.Threa
java.util.concurrent.Threa
java.lang.Thread.run(Threa
note The full stack trace of the root cause is available in the Apache Tomcat/7.0.42 logs.
java6.jpg
ASKER
I do see simple.java servlet in under default package as below
Do i need to put it in any package?
WelcomeServlet.java looks like
login.html as below
lastly web.xml as below
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.*;
import javax.servlet.http.*;
public class Simple extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html") ;
PrintWriter out = response.getWriter();
String p=request.getParameter("userPass");
if(p.equals("servlet")){
RequestDispatcher rd=request.getRequestDispatcher("wel come");
rd.forward(request, response);
}
else{
out.print("Sorry username or password error!");
RequestDispatcher rd=request.getRequestDispatcher("log in.html");
rd.include(request, response);
}
}
}
Do i need to put it in any package?
WelcomeServlet.java looks like
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class WelcomeServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
String n=request.getParameter("userName");
out.print("Welcome "+n);
}
}login.html as below
<form action="go" method="get">
Name:<input type="text" name="userName"/><br/>
Password:<input type="password" name="userPass"/><br/>
<input type="submit" value="login"/>
</form>lastly web.xml as below
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>Simple</servlet-name>
<servlet-class>Simple</servlet-class>
</servlet>
<servlet>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>WelcomeServlet</servlet-name>
<servlet-class>WelcomeServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Simple</servlet-name>
<url-pattern>/go</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>WelcomeServlet</servlet-name>
<url-pattern>/welcome</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>login.html</welcome-file>
</welcome-file-list>
</web-app>ASKER
I do not see any .class files under
web-inf/classes
How to compile and generate the class files in the eclipse itself so that my code get to see generated .class file of the servlet?
please advise
web-inf/classes
How to compile and generate the class files in the eclipse itself so that my code get to see generated .class file of the servlet?
please advise
ASKER
I created separate dynamic web project from scratch. Then i copied individually src and webcontent. Then run on server. then it all worked fine
happy to see that you solved the probelm
ASKER
Now i right clicked and went to project facets and selected 'Dynamic Project 3.0 and then java 1.6' and run as Tomcat 7
when i run on tomcat 7 i see html page(http://localhost:8080/requestdispatcher/) but when i gave username gp and password servlet getting below error
HTTP Status 500 - Simple : Unsupported major.minor version 51.0 (unable to load class Simple)
--------------------------
type Exception report
message Simple : Unsupported major.minor version 51.0 (unable to load class Simple)
description The server encountered an internal error that prevented it from fulfilling this request.
exception
java.lang.UnsupportedClass
org.apache.catalina.loader
org.apache.catalina.loader
org.apache.catalina.loader
org.apache.catalina.loader
org.apache.catalina.authen
org.apache.catalina.valves
org.apache.catalina.valves
org.apache.catalina.connec
org.apache.coyote.http11.A
org.apache.coyote.Abstract
org.apache.tomcat.util.net
java.util.concurrent.Threa
java.util.concurrent.Threa
java.lang.Thread.run(Threa
note The full stack trace of the root cause is available in the Apache Tomcat/7.0.42 logs.