The deployment descriptor is an xml file that contains the basic and most important information that is required to deploy a web application (Servlet)
Without this, the web server would not know, which requests to entertain/consider as requests to access this servlet.
In computer programming, a file descriptor (FD) is an abstract indicator for accessing a file. The term is generally used in POSIX operating systems.
Yes, you can deploy a servlet as a web service. By exposing the servlet's functionalities through HTTP requests, you can create a RESTful web service that clients can interact with using standard HTTP methods like GET, POST, PUT, and DELETE. Additionally, you can also use libraries like JAX-RS or Spring to simplify the process of building and deploying web services in a servlet container. This allows clients to communicate with the servlet over the web using standard protocols.
get servlet context path from EJB
Java Servlet Development Kit is an integrated development kit used to build, test, and deploy Java Servlet applications. JSDK allows most standard Web server such as Netscape servers, IIS, Apache and others to load servlets . JSDK is a suite of software for easing the development of Java servlets.
There is no specific/separate servlet development kit. Servlets can be developed and compiled using the standard JDK and JRE. The only difference being the fact that - to run them you need a web server
Deployment Descriptor is probably the most important part of any web application. Even if you have all your servlets, JSPs, Jars etc set up properly, the system wouldn't run fine unless you set up the deployment descriptor properly
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.
used for xml mappings
Step 1: Write the servlet.Follow along as we write the ServletSample servlet and give you tips for writing your own servlets.Step 2: Compile the servlet.Use Qshell to compile the sample servlet and your own servlets.Step 3: Package and deploy an applicationUse the WebSphere Development Studio Client to package compiled code into a Web module before you install it on the server and to create a deployment descriptor (web.xml) file. For more information, see the WebSphere Development Studio Client.Step 4:Test the servletRun the ServletSample to make sure it works.
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
ServletContext Defines a set of methods that a servlet uses to communicate with its servlet container.ServletConfig is a servlet configuration object used by a servlet container used to pass information to a servlet during initialization. All of its initialization parameters can ONLY be set in deployment descriptor.The ServletContext object is contained within the ServletConfig object, which the Web server provides the servlet when the servlet is initialized.You can specify param-value pairs for ServletContext object in tags in web.xml file.The ServletConfig parameters are specified for a particular servlet and are unknown to other servlets. The ServletContext parameters are specified for an entire application outside of any particular servlet and are available to all the servlets within that application.By Santanu
SERVLETS JSP 1. Servlet is a java class. 2. Servlet is a single instance multiple thread web application, In which HTML code can be included in java code. 3. In servlets the presentation logic and the B.logic is tightly coupled. 4. For every modification done in servlet program, we need to recompile and reload the application. 5. In servlets implicit objects are not available. 6. Servlets are supported to HTTP, FTP, and SMTP protocols. 7. Sevlets are need Deployment Descriptor file (web.xml) 1. Jsp is a file. 2. In jsp java code can be included in HTML code by using special tags. 3. In jsp's the presentation logic and B.logic are separated by defining the java beans. 4. If any modifications done in jsp's without recompiling and reloading , the modifications are reflected. 5. In jsp's implicit objects are available which is we can implement directly into jsp pages. 6. Jsp are supported to HTTP protocol only. 7. No need of Deployment Descriptor file (web.xml) rajus_1219@yahoo.co.in
Http servlet and Generic servlet
Servlet Chaining means the output of one servlet act as a input to another servlet. Servlet Aliasing allows us to invoke more than one servlet in sequence when the URL is opened with a common servlet alias. The output from first Servlet is sent as input to other Servlet and so on. The Output from the last Servlet is sent back to the browser. The entire process is called Servlet Chaining.
In a servlet class, you can obtain protocol-dependent services by leveraging the HttpServletRequest and HttpServletResponse objects that are passed to the servlet's doGet() or doPost() methods. These objects provide methods to access protocol-specific information, such as request headers, query parameters, and session management. For example, you can use request.getScheme() to determine the request protocol (HTTP or HTTPS) and response.setContentType() to set the appropriate content type based on the requested resource. Additionally, you can utilize the servlet context to access resources and configuration settings relevant to the application's deployment environment.
No. Javascript code can be present inside a JSP but not inside a servlet. A Servlet is a pure java class.
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.