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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 are the servlet config methods?
Methods in the Servlet ContextApart from setting and getting custom attributes used for our application, the context also contains various methods that we can use to retrieve specific information about the application and other aspects. They are:• getAttributeNames() - Returns an Enumeration object containing the attribute names available within this servlet context.• getContext(String uripath) - Returns a ServletContext object that corresponds to a specified URL on the server.• getInitParameter(String name) - Returns a string containing the value of the named context-wide initialization parameter, or null if the parameter does not exist.• getInitParameterNames() - Returns the names of the context's initialization parameters as an Enumeration of string objects, or an empty Enumeration if the context has no initialization parameters.• getMajorVersion() - Returns the major version as an int of the Java Servlet API that this Servlet Container supports.• getMimeType(java.lang.String file) - Returns the MIME type as a string of the specified file, or null if the MIME type is not known.• getMinorVersion() - Returns the minor version as an int of the Servlet API that this Servlet Container supports.• getNamedDispatcher(String name) Returns a RequestDispatcher object that acts as a wrapper for the named servlet.• getRealPath(String path) - Returns a string containing the real path for a given virtual path.• getRequestDispatcher(String path) Returns a RequestDispatcher object that acts as a wrapper for the resource located at the given path.• getResource(String path) - Returns a URL to the resource that is mapped to a specified path.• getResourceAsStream(String path) - Returns the resource located at the named path as an InputStream object.• getServerInfo() Returns the name and version as a String of the Servlet Container on which the servlet is running.
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.
How do you give connection between HTML and java servlet?
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.
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.
