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
I think the name of the jsp file is included in the web.xml of the 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.
You cannot. HTML is a static file and it cannot interact with a Java Servlet. A Servlet can always redirect to a HTML page but the other way round cannot happen.
You need a form to pass value to a servlet. In the form tag, the action element passes the value into the servlet.
How to convert bytecode to .jpeg file in servlet? Thanks
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
The javax.servlet package defines 12 interfaces, 7 classes, and 2 exceptions. The Interfaces are as follows:• Filter:- Preprocessor of the request before it reaches a servlet. It can also be a postprocessor of the response leaving a servlet. It can modify a request or response (for example, change headers), the request to a resource (a servlet or static content), or the response from a resource.• RequestDispatcher:- This is the servlet version of a redirect. It enables requests to be processed and then forwarded to other components of a Web application, such as another servlet, HTML file, or JSP file.• Servlet:- Defines the life-cycle methods that are implemented by all servlets.• ServletConfig:- This class has the methods for accessing the servlet configuration information such as the servlets name (from the web.xml file), the initialization parameters, and the ServletContext object.• ServletContext:- These methods enable your servlet to communicate with its servlet container. This is how you get the MIME type of a file, dispatch requests, or write to a log file. Notice that this information has application scope. The most important features of the ServletContext are application-scope attributes access, logging, and context initialization parameters.• ServletContextAttributeListener:- Implementations of this interface receive notifications of changes to the attribute list on the servlet context of a Web application. Supports the handling of the ServletContextAttributeEvent class.• ServletContextListener:- An interface that supports the handling of the ServletContextEvent class. Defines a set of methods that a servlet uses to communicate with its servlet container. It can get the MIME type of a file, dispatch requests, or write to a log file. Notice that there is one context per "Web application" per Java Virtual Machine. The specification defines a "Web application" as a collection of servlets and content installed under a specific subset of the server's URL namespace, such as /catalog, and possibly installed via a .war file.• ServletRequest:- This interface forms the base for the class that provides client request information to a servlet. It is protocol-independent.• ServletResponse:- This interface forms the base for the class that represents the response sent from the servlet to the client.• SingleThreadModel:- An interface that ensures a given servlet handles only one request at a time.
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.
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.
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.
I have created a .jsp file, in which, I am calling a class.method() through TagLib. REQUIREMENT is, I want to call a servlet instead of a simple class. And Servlet will get the response, and request object from Jsp, and manipulate that, and produce the response object, and control is transfered back to JSP again.
Http servlet and Generic servlet