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You Run a Servlet by deploying it on the server, which in this case is tomcat. We need to deploy the servlet in the Web Applications context.
When we talk of a Web application's context, we are referring to that Web application's root directory or path within a particular server. A special directory exists within the application hierarchy named WEB-INF. This directory contains all things related to the application that aren't in the document root of the application. It is this WEB-INF directory that is the Web application's root directory, also referred to as the context. The most important file here is web.xml, the name of the WebApp deployment descriptor.
Let us take a look at the various contents (files & folders) that will be present inside this WEB-INF directory:
1. /WEB-INF/web.xml - This is the Deployment Descriptor file
2. /WEB-INF/classes/ - This is the directory where all your java class files will be placed
3. /WEB-INF/lib/ - This is the folder where all your JAR files go.
my tomcat is installed in c:\dev\java\Jakarta-tomcat-4.0.1. This is my TOMCAT_HOME. Remember that, this path that is referred by TOMCAT_HOME might vary from PC to PC depending on the installation preferences of the user.
To Deploy the Servlet, you need to place the .class file corresponding to your servlet in the /WEB-INF/classes/ folder
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Differniate between applet and servlet in java?
Applet: It is run on browser, i mean client side. Servlet: It is run on server, i mean server side.
What is servlet mapping?
A Servlet Mapping is a directive in the web.xml that tells the Servlet Container which class to use when a particular Servlet is called. A Servlet is a class within your Java Web Application. Let's say you have a servlet called MyServlet in the com.example.servlet package. You would need to have a Servlet Mapping pointing the path "/MyServlet" to the "com.example.servlet.MyServlet" class. Without the servlet mapping, you would not be able to invoke your servlet because the Servlet container would not know where it is. JSPs are different - they do not need mappings like this. JSPs exist within the WebRoot of the application, so they are always available. Servlets exist in the WEB-INF\Classes directory once your application is deployed.
What is servlet and why it is used?
servlet is a small program which run on serverside,and it can not be downloaded at client side. java servlets dynamically extends the functionalities of a web server. main use is: session tracking: no of users (unique) visited u'r website. in order to use cookies..
Can you use constructor in servlet?
Yes you can but it is not required. A Servlet is nothing but another .java file and all rules that are applicable to standard Java classes are applicable to them. Note: Even if you write a constructor in a servlet, it will not get executed.
Difference between HTTP servlet and Generic servlet?
The difference is that a GenericServlet has no defined protocol (it is "generic"), while HttpServler uses the HTTP protocol. HttpServlet is a subclass of GenericServlet with the purpose of creating a servlet for a web site.
How do you compile servlet in java using tomcat?
Tomcat is a server. It is used to deploy and run Servlets and not compile them. A Servlet is a java file and has to be compiled just like any other Java Class.
How do you run servlets?
Servlets can be run on Web servers like weblogic or websphere or tomcat. The servlet and other components of the j2ee project need to be packaged as an EAR and then deployed on the server. Based on the deployment descriptor we can access the servlet.
What is the Apache TomCat webserver?
Apache Tomcat is a servlet container developed by the Apache Software Foundation (ASF). Tomcat implements the Java Servlet and the JavaServer Pages (JSP) specifications from Sun Microsystems, and provides a "pure Java" HTTP web server environment for Java code to run. Stephen Williamson, Server Engineer, http://www.HostMySite.com?utm_source=bb
How to run servlet page in tomcat5.5 server?
How to run servlet page in tomcat5.5 server?"
Why no need of main in servlet?
I think you mean: why isn't there a function required in a servlet like the following? public static void main(String[] args) { } Because the main() method is what the Java VM 'boots up' into...it's the first thing the JVM executes. A servlet, however, is running inside a servlet container (e.g., Tomcat), which is running inside a JVM. *That* JVM gets started with a main() method, but unless you intend to run your servlet from the commandline, there's no explicit need for a main() method.
Where do servlets execute?
On the Server in which the Web Application is deployed. For Ex: Tomcat, weblogic, websphere are all some servers in which a servlet can execute
Where do you deploy the servlet files?
The Servlet file and all other components of the web/j2ee project get deployed onto a web server (Websphere, Weblogic, Tomcat etc) They are packaged into an Enterprise Archive file (EAR) and deployed on the server
When should you use jsp and servlet in your project?
JSP and servlets are used in when you are building a website that provides a server sided service, for example connecting to a database is a service. == == JSP/Servlets are java code that perform the backend operations for web pages. Such servlets run in a java container, such as JBoss or Tomcat. Where you would use these would be in a web-based environment where you wanted to run the backend on Java, as opposed to PHP, Perl, etc. As an example, eBay is run by JSP/Servlet technology. However, JSP/Servlet technology is much more complicated than scripting languages, but well worth learning.
Differniate between applet and servlet in java?
Applet: It is run on browser, i mean client side. Servlet: It is run on server, i mean server side.
Describe the life cycle of servelet?
Each servlet has the same life cycle: * A server loads and initializes the servlet * The servlet handles zero or more client requests * The server removes the servlet (some servers do this step only when they shut down) == When a server loads a servlet, the server runs the servlet's init method. Initialization completes before client requests are handled and before the servlet is destroyed. Even though most servlets are run in multi-threaded servers, servlets have no concurrency issues during servlet initialization. The server calls the init method once, when the server loads the servlet, and will not call the init method again unless the server is reloading the servlet. The server can not reload a servlet until after the server has destroyed the servlet by calling the destroy method. == After initialization, the servlet is able to handle client requests. This part of the servlet life cycle was handled in the previous lesson. == Servlets run until the server are destroys them, for example, at the request of a system administrator. When a server destroys a servlet, the server runs the servlet's destroy method. The method is run once; the server will not run that servlet again until after the server reloads and reinitializes the servlet. When the destroy method runs, another thread might be running a service request. The Handling Service Threads at Servlet Termination lesson shows you how to provide a clean shutdown when there could be long-running threads still running service requests.
How does Apache httpd work?
Tomcat is a servlet container, and the following is how a servlet container works The init, service, and destroy methods are the servlet's lifecycle methods. The init method is called once by the servlet container after the servlet class has been instantiated to indicate to the servlet that it being placed into service. The init method must complete successfully before the servlet can receive any requests. A servlet programmer can override this method to write initialization code that needs to run only once, such as loading a database driver, initializing values, and so on. In other cases, this method is normally left blank. The service method is then called by the servlet container to allow the servlet to respond to a request. The servlet container passes a javax.servlet.ServletRequest object and a javax.servlet.ServletResponse object. The ServletRequest object contains the client's HTTP request information and the ServletResponse encapsulates the servlet's response. These two objects enable you to write custom code that determines how the servlet services the client request. The servlet container calls the destroy method before removing a servlet instance from service. This normally happens when the servlet container is shut down or when the servlet container needs some free memory. This method is called only after all threads within the servlet's service method have exited or after a timeout period has passed. After the servlet container calls destroy, it will not call the service method again on this servlet. The destroy method gives the servlet an opportunity to clean up any resources that are being held (for example, memory, file handles, and threads) and make sure that any persistent state is synchronized with the servlet's current state in memory. For Better Picture, Visit below article full of images to clear the concept : http://shivasoft.in/blog/java/servlet/how-container-handles-the-servlet-request/
Difference between apache and http server?
"Apache" is the name of a foundation that write open-source software. Apache HTTPD is a web server written in portable C (when people say "Apache", they usually mean Apache HTTPD.) It mostly serves static content by itself, but there are many add-on modules (some of which come with Apache itself) that let it modify the content and also serve dynamic content written in Perl, PHP, Python, Ruby, or other languages. Tomcat is primarily a servlet/JSP container. It's written in Java. It can serve static content, too, but its main purpose is to host servlets and JSPs. Although it's possible to get Tomcat to run Perl scripts and the like, you wouldn't use Tomcat unless most of your content was Java. "Apache" is the name of a foundation that write open-source software. Apache HTTPD is a web server written in portable C (when people say "Apache", they usually mean Apache HTTPD.) It mostly serves static content by itself, but there are many add-on modules (some of which come with Apache itself) that let it modify the content and also serve dynamic content written in Perl, PHP, Python, Ruby, or other languages. Tomcat is primarily a servlet/JSP container. It's written in Java. It can serve static content, too, but its main purpose is to host servlets and JSPs. Although it's possible to get Tomcat to run Perl scripts and the like, you wouldn't use Tomcat unless most of your content was Java.
