A servlet is a small Java program that runs within a Web server. Servlets receive and respond to requests from Web clients, usually across HTTP, the HyperText Transfer Protocol.
To implement this interface, you can write a generic servlet
javax.servlet.GenericServlet or an HTTP servlet that
This interface defines methods to initialize a servlet, to service requests, and to remove a servlet from the server. These are known as life-cycle methods and are called in the following sequence:
servicemethod are handled.
destroymethod, then garbage collected and finalized.
In addition to the life-cycle methods, this interface
getServletConfig method, which the servlet
can use to get any startup information, and the
method, which allows the servlet to return basic information about itself,
such as author, version, and copyright.
|Method from javax.servlet.Servlet Summary:|
|destroy, getServletConfig, getServletInfo, init, service|
|Method from javax.servlet.Servlet Detail:|
public void destroy()
This method gives the servlet an opportunity to clean up any resources that are being held (for example, memory, file handles, threads) and make sure that any persistent state is synchronized with the servlet's current state in memory.
public ServletConfig getServletConfig()
Implementations of this interface are responsible for storing the
public String getServletInfo()
The string that this method returns should be plain text and not markup of any kind (such as HTML, XML, etc.).
public void init(ServletConfig config) throws ServletException
The servlet container calls the
The servlet container cannot place the servlet into service
public void service(ServletRequest req, ServletResponse res) throws ServletException, IOException
This method is only called after the servlet's
The status code of the response always should be set for a servlet that throws or sends an error.
Servlets typically run inside multithreaded servlet containers that can handle multiple requests concurrently. Developers must be aware to synchronize access to any shared resources such as files, network connections, and as well as the servlet's class and instance variables. More information on multithreaded programming in Java is available in the Java tutorial on multi-threaded programming.