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How to run servlet by using main?

How can I use main to run servlet?I cannot put request and response object into doGet(request, response) methodI want this because I want to run this servlet daily and I plan to put it in cron jobCalvin

[237 byte] By [calvinchoi] at [2007-9-26 1:36:25]

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# 1

Hi,

No, That means that if you are making an application you need a functioning main(). However if you are using an applet or servlet etc. Then the JVM in the browser already has a main() so you don't need to supply it.

Still your question is not that much clear. If you want to put it in a cron tab, you can run as an ordinary application and you can put it.

Also please see the URL.

http://www.lindengrun.com/java/Servlet/HelloWorld.html

I hope this will help you.

Thanks

Bakrudeen

Technical Support Engineer

Sun MicroSystems Inc, India

bakrudeen_indts at 2007-6-29 2:21:56 >

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# 2

What i want to do is running those servlet without using browserCan I run it just in dos shell or in unix shell?

calvinchoi at 2007-6-29 2:21:56 >

# 3

Perhaps you cannot run servlet without using browser. But you can make that program as an application in order to run in Dos or Unix shell.

But still you can run servlet without using browser How?

You can debug servlets with the same jdb commands you use to debug an applet or an application. The JavaTM Servlet Development Kit (JSDK) provides a standalone program

called servletrunner that lets you run a servlet without a web browser. On most systems, this program simply runs the java sun.servlet.http.HttpServer command. You

can, therefore, start a jdb session with the HttpServer class.

A key point to remember when debugging servlets is that Java Web server and servletrunner achieve servlet loading and unloading by not including the servlets directory on

the CLASSPATH. This means the servlets are loaded using a custom classloader and not the default system classloader.

Running servletrunner in Debug Mode

Running Java Web ServerTM in Debug Mode

Running servletrunner in Debug Mode

In this example, the servlets examples directory is included on the CLASSPATH. You can configure the CLASSPATH for debug mode as follows:

Unix

$ export CLASSPATH=./lib/jsdk.jar:./examples:$CLASSPATH

Windows

$ set CLASSPATH=lib\jsdk.jar;examples;%classpath%

To start the servletrunner program you can either run the supplied startup script called servletrunner or just supply the servletrunner classes as a parameter to jdb. This

example uses the parameter to servletrunner.

$ jdb sun.servlet.http.HttpServer

Initializing jdb...

0xee2fa2f8:class(sun.servlet.http.HttpServer)

> stop in SnoopServlet.doGet

Breakpoint set in SnoopServlet.doGet

> run

run sun.servlet.http.HttpServer

running ...

main[1] servletrunner starting with settings:

port = 8080

backlog = 50

max handlers = 100

timeout = 5000

servlet dir = ./examples

document dir = ./examples

servlet propfile = ./examples/servlet.properties

To run SnoopServlet in debug mode, enter the following URL in a browser where yourmachine is the machine where you started servlet runner and 8080 is the port number

displayed in the settings output.

http://yourmachine:8080/servlet/SnoopServlet

In this example jdb stops at the first line of the servlet's doGet method. The browser will wait for a response from your servlet until a timeout is reached.

main[1] SnoopServlet: init

Breakpoint hit: SnoopServlet.doGet (SnoopServlet:45)

Thread-105[1]

We can use the list command to work out where jdb has stopped in the source.

Thread-105[1] list

41throws ServletException, IOException

42{

43PrintWriterout;

45 =>res.setContentType("text/html");

46out = res.getWriter ();

48out.println("<html>");

49out.println("<head>

<title>Snoop Servlet

</title></head>");

Thread-105[1]

The servlet can continue using the cont command.

Thread-105[1] cont

Running Java Web Server in Debug Mode

The JSDK release does not contain classes available in the Java Web server and it also has its own special servlet configuration. If you cannot run your servlet from

servletrunner, then the other option is to run the Java Web server in debug mode.

To do this add the -debug flag for the first parameter after the java program. For example in the script bin/js change the JAVA line to look like the following. In releases prior

to the Java 2 platform release, you will also need to change the program pointed to by the variable $JAVA to java_g instead of java.

Before:

exec $JAVA $THREADS $JITCOMPILER $COMPILER $MS $MX \

After:

exec $JAVA -debug $THREADS $JITCOMPILER

$COMPILER $MS $MX \

Here is how to remotely connect to the Java Web Server. The agent password is generated on the standard output from the Java Web Server so it can be redirected into a file

somewhere. You can find out where by checking the Java Web Server startup scripts.

jdb -host localhost -password <the agent password>

The servlets are loaded by a separate classloader if they are contained in the servlets directory, which is not on the CLASSPATH used when starting the Java Web server.

Unfortunately, when debugging remotely with jdb, you cannot control the custom classloader and request it to load the servlet, so you have to either include the servlets

directory on the CLASSPATH for debugging or load the servlet by requesting it through a web browser and then placing a breakpoint once the servlet has run.

In this next example, the jdc.WebServer.PasswordServlet is included on the CLASSPATH when Java Web server starts. The example sets a breakpoint to stop in the service

method of this servlet, which is the main processing method of this servlet.

The Java Web Server standard output produces this message, which lets you proceed with the remote jdb session:

Agent password=3yg23k

$ jdb -host localhost -password 3yg23k

Initializing jdb...

> stop in jdc.WebServer.PasswordServlet:service

Breakpoint set in jdc.WebServer.PasswordServlet.service

> stop

Current breakpoints set:

jdc.WebServer.PasswordServlet:111

The second stop lists the current breakpoints in this session and shows the line number where the breakpoint is set. You can now call the servlet through your HTML page. In

this example, the servlet is run as a POST operation

</FORM>

You get control of the Java Web Server thread when the breakpoint is reached, and you can continue debugging using the same techniques as used in the Remote Debugging

section.

Breakpoint hit: jdc.WebServer.PasswordServlet.service

(PasswordServlet:111) webpageservice Handler[1] where

[1] jdc.WebServer.PasswordServlet.service

(PasswordServlet:111)

[2] javax.servlet.http.HttpServlet.service

(HttpServlet:588)

[3] com.sun.server.ServletState.callService

(ServletState:204)

[4] com.sun.server.ServletManager.callServletService

(ServletManager:940)

[5] com.sun.server.http.InvokerServlet.service

(InvokerServlet:101)

A common problem when using the Java WebServer and other servlet environments is that Exceptions are thrown but are caught and handled outside the scope of your servlet.

The catch command allows you to trap all these exceptions.

webpageservice Handler[1] catch java.io.IOException

webpageservice Handler[1]

Exception: java.io.FileNotFoundException

at com.sun.server.http.FileServlet.sendResponse(

FileServlet.java:153)

at com.sun.server.http.FileServlet.service(

FileServlet.java:114)

at com.sun.server.webserver.FileServlet.service(

FileServlet.java:202)

at javax.servlet.http.HttpServlet.service(

HttpServlet.java:588)

at com.sun.server.ServletManager.callServletService(

ServletManager.java:936)

at com.sun.server.webserver.HttpServiceHandler

.handleRequest(HttpServiceHandler.java:416)

at com.sun.server.webserver.HttpServiceHandler

.handleRequest(HttpServiceHandler.java:246)

at com.sun.server.HandlerThread.run(

HandlerThread.java:154)

This simple example was generated when the file was not found, but this technique can be used for problems with posted data. Remember to use cont to allow the web server

to proceed. To clear this trap use the ignore command.

webpageservice Handler[1] ignore java.io.IOException

webpageservice Handler[1] catch

webpageservice Handler[1]

I hope this will help you.

Thanks

Bakrudeen

bakrudeen_indts at 2007-6-29 2:21:56 >

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