Class HttpServlet

java.lang.Object
javax.servlet.GenericServlet
javax.servlet.http.HttpServlet
All Implemented Interfaces:
Serializable, Servlet, ServletConfig
public abstract class HttpServlet extends GenericServlet implements Serializable
The mother-of-all-HttpServlets. Every normal http servlet extends this class and overrides either the doGet or doPost methods (or both). The server calls service. Service in its turn calls doGet, doPost, whatever, depending on the client's request.
Since:
Servlet API 1.0
Version:
Servlet API 2.2
See Also:

  • Constructor Details

    • HttpServlet

      public HttpServlet()
      Does nothing
      Since:
      Servlet API 1.0

  • Method Details

    • doDelete

      protected void doDelete(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
      This method is called on a "DELETE" request. The default implementation is that HttpServletResponse.SC_BAD_REQUEST (error nr: 400) and the message "Method \"DELETE\" is not supported by this servlet" is returned to the client.
      Throws:
      ServletException - if an Servlet Exception occurs
      IOException - if an IOException occurs
      Since:
      Servlet API 2.0

    • doGet

      protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
      This method is called on a "GET" request. The default implementation is that HttpServletResponse.SC_BAD_REQUEST (error nr: 400) and the message "Method \"GET\" is not supported by this servlet" is returned to the client.
      Throws:
      ServletException - if an Servlet Exception occurs
      IOException - if an IOException occurs
      Since:
      Servlet API 1.0

    • doOptions

      protected void doOptions(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
      This method is called on a "OPTIONS" request. It tells the client which methods are supported by the servlet.
      This comes down to an implementation where HEAD, TRACE and OPTIONS are supported by default because this class contains default implementations of them. GET, POST, DELETE and PUT are added to this list if the subclass has its own implementation of the doGet, doPost, doDelete or doPut method respectively. Note:
      This implementation is probably not the most efficient one, but the whole OPTIONS thing is intended for debugging purposes, and this implementation does the job.
      Throws:
      ServletException - if an Servlet Exception occurs
      IOException - if an IOException occurs
      Since:
      Servlet API 2.0

    • doPost

      protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
      This method is called on a "POST" request. The default implementation is that HttpServletResponse.SC_BAD_REQUEST (error nr: 400) and the message "Method \"POST\" is not supported by this servlet" is returned to the client.
      Throws:
      ServletException - if an Servlet Exception occurs
      IOException - if an IOException occurs
      Since:
      Servlet API 1.0

    • doPut

      protected void doPut(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
      This method is called on a "PUT" request. The default implementation is that HttpServletResponse.SC_BAD_REQUEST (error nr: 400) and the message "Method \"PUT\" is not supported by this servlet" is returned to the client.
      Throws:
      ServletException - if an Servlet Exception occurs
      IOException - if an IOException occurs
      Since:
      Servlet API 2.0

    • doTrace

      protected void doTrace(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
      This method is called on a "TRACE" request. This method is for debugging purposes.
      When a client makes a TRACE request the following is returned:
      content type = "message/http"
      message size: <size of the complete message>
      first line of the message : TRACE <requested uri> <protocol>
      on the following lines all the request header names and values
      Throws:
      ServletException - if an Servlet Exception occurs
      IOException - if an IOException occurs
      Since:
      Servlet API 2.0

    • getLastModified

      protected long getLastModified(HttpServletRequest request)
      Returns the time the requested uri was last modified in seconds since 1 january 1970. Default implementation returns -1.
      Since:
      Servlet API 1.0

    • service

      protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
      This method looks whether the request is a POST, GET, etc method, and then calls the appropriate doPost, doGet, whatever method.
      If the request method is something it can't handle it sends a HttpServletResponse.SC_BAD_REQUEST error through the response.
      Throws:
      ServletException - an error has occured
      IOException - an error has occured
      Since:
      Servlet API 1.0

    • service

      public void service(ServletRequest request, ServletResponse response) throws ServletException, IOException
      Frontend for calling service(HttpServletRequest,HttpServletResponse).

      This method tries to typecast the ServletRequest and the ServletResponse to HttpServletRequest and HttpServletResponse and then call service(HttpServletRequest,HttpServletResponse).

      Specified by:
      service in interface Servlet
      Specified by:
      service in class GenericServlet
      Parameters:
      request - The client's request
      response - The class to write the response date to.
      Throws:
      ServletException - an error has occured
      IOException - an error has occured
      Since:
      Servlet API 1.0
      See Also: