javax.servlet.http
Class HttpServlet
java.lang.Object
|
+--javax.servlet.GenericServlet
|
+--javax.servlet.http.HttpServlet
- All Implemented Interfaces:
- java.io.Serializable, Servlet, ServletConfig
- Direct Known Subclasses:
- AdminServlet, CGI, Debug, Dump, Forward, HttpJspBase, JspServlet, NotFoundServlet, RequestDispatchTest, SessionDump
- public abstract class HttpServlet
- extends GenericServlet
- implements java.io.Serializable
Provides an abstract class to be subclassed to create
an HTTP servlet suitable for a Web site. A subclass of
HttpServlet
must override at least
one method, usually one of these:
-
doGet
, if the servlet supports HTTP GET requests
-
doPost
, for HTTP POST requests
-
doPut
, for HTTP PUT requests
-
doDelete
, for HTTP DELETE requests
-
init
and destroy
,
to manage resources that are held for the life of the servlet
-
getServletInfo
, which the servlet uses to
provide information about itself
There's almost no reason to override the service
method. service
handles standard HTTP
requests by dispatching them to the handler methods
for each HTTP request type (the do
XXX
methods listed above).
Likewise, there's almost no reason to override the
doOptions
and doTrace
methods.
Servlets typically run on multithreaded servers,
so be aware that a servlet must handle concurrent
requests and be careful to synchronize access to shared resources.
Shared resources include in-memory data such as
instance or class variables and external objects
such as files, database connections, and network
connections.
See the
Java Tutorial on Multithreaded Programming for more
information on handling multiple threads in a Java program.
- Version:
- $Version$
- Author:
- Various
- See Also:
- Serialized Form
Constructor Summary |
HttpServlet()
Does nothing, because this is an abstract class. |
Methods inherited from class javax.servlet.GenericServlet |
destroy, getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, init, init, log, log |
Methods inherited from class java.lang.Object |
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
HttpServlet
public HttpServlet()
- Does nothing, because this is an abstract class.
service
public void service(ServletRequest req,
ServletResponse res)
throws ServletException,
java.io.IOException
- Dispatches client requests to the protected
service
method. There's no need to
override this method.
- Overrides:
service
in class GenericServlet
- Parameters:
req
- the HttpServletRequest
object that
contains the request the client made of
the servletresp
- the HttpServletResponse
object that
contains the response the servlet returns
to the client- Throws:
java.io.IOException
- if an input or output error occurs
while the servlet is handling the
TRACE requestServletException
- if the request for the
TRACE cannot be handled- See Also:
Servlet.service(javax.servlet.ServletRequest, javax.servlet.ServletResponse)
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