Servlet.java
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上传日期:2022-07-20
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文件大小:9k
源码类别:
数据库编程
开发平台:
Java
- /*
- * The Apache Software License, Version 1.1
- *
- * Copyright (c) 1999 The Apache Software Foundation. All rights
- * reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in
- * the documentation and/or other materials provided with the
- * distribution.
- *
- * 3. The end-user documentation included with the redistribution, if
- * any, must include the following acknowlegement:
- * "This product includes software developed by the
- * Apache Software Foundation (http://www.apache.org/)."
- * Alternately, this acknowlegement may appear in the software itself,
- * if and wherever such third-party acknowlegements normally appear.
- *
- * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
- * Foundation" must not be used to endorse or promote products derived
- * from this software without prior written permission. For written
- * permission, please contact apache@apache.org.
- *
- * 5. Products derived from this software may not be called "Apache"
- * nor may "Apache" appear in their names without prior written
- * permission of the Apache Group.
- *
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
- * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
- * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
- * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
- * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- * ====================================================================
- *
- * This software consists of voluntary contributions made by many
- * individuals on behalf of the Apache Software Foundation. For more
- * information on the Apache Software Foundation, please see
- * <http://www.apache.org/>.
- *
- * ====================================================================
- *
- * This source code implements specifications defined by the Java
- * Community Process. In order to remain compliant with the specification
- * DO NOT add / change / or delete method signatures!
- */
- package javax.servlet;
- import java.io.IOException;
- /**
- * Defines methods that all servlets must implement.
- *
- * <p>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.
- *
- * <p>To implement this interface, you can write a generic servlet
- * that extends
- * <code>javax.servlet.GenericServlet</code> or an HTTP servlet that
- * extends <code>javax.servlet.http.HttpServlet</code>.
- *
- * <p>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:
- * <ol>
- * <li>The servlet is constructed, then initialized with the <code>init</code> method.
- * <li>Any calls from clients to the <code>service</code> method are handled.
- * <li>The servlet is taken out of service, then destroyed with the
- * <code>destroy</code> method, then garbage collected and finalized.
- * </ol>
- *
- * <p>In addition to the life-cycle methods, this interface
- * provides the <code>getServletConfig</code> method, which the servlet
- * can use to get any startup information, and the <code>getServletInfo</code>
- * method, which allows the servlet to return basic information about itself,
- * such as author, version, and copyright.
- *
- * @author Various
- * @version $Version$
- *
- * @see GenericServlet
- * @see javax.servlet.http.HttpServlet
- *
- */
- public interface Servlet {
- /**
- * Called by the servlet container to indicate to a servlet that the
- * servlet is being placed into service.
- *
- * <p>The servlet container calls the <code>init</code>
- * method exactly once after instantiating the servlet.
- * The <code>init</code> method must complete successfully
- * before the servlet can receive any requests.
- *
- * <p>The servlet container cannot place the servlet into service
- * if the <code>init</code> method
- * <ol>
- * <li>Throws a <code>ServletException</code>
- * <li>Does not return within a time period defined by the Web server
- * </ol>
- *
- *
- * @param config a <code>ServletConfig</code> object
- * containing the servlet's
- * configuration and initialization parameters
- *
- * @exception ServletException if an exception has occurred that
- * interferes with the servlet's normal
- * operation
- *
- * @see UnavailableException
- * @see #getServletConfig
- *
- */
- public void init(ServletConfig config) throws ServletException;
- /**
- *
- * Returns a {@link ServletConfig} object, which contains
- * initialization and startup parameters for this servlet.
- * The <code>ServletConfig</code> object returned is the one
- * passed to the <code>init</code> method.
- *
- * <p>Implementations of this interface are responsible for storing the
- * <code>ServletConfig</code> object so that this
- * method can return it. The {@link GenericServlet}
- * class, which implements this interface, already does this.
- *
- * @return the <code>ServletConfig</code> object
- * that initializes this servlet
- *
- * @see #init
- *
- */
- public ServletConfig getServletConfig();
- /**
- * Called by the servlet container to allow the servlet to respond to
- * a request.
- *
- * <p>This method is only called after the servlet's <code>init()</code>
- * method has completed successfully.
- *
- * <p>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
- * <a href="http://java.sun.com/Series/Tutorial/java/threads/multithreaded.html">
- * the Java tutorial on multi-threaded programming</a>.
- *
- *
- * @param req the <code>ServletRequest</code> object that contains
- * the client's request
- *
- * @param res the <code>ServletResponse</code> object that contains
- * the servlet's response
- *
- * @exception ServletException if an exception occurs that interferes
- * with the servlet's normal operation
- *
- * @exception IOException if an input or output exception occurs
- *
- */
- public void service(ServletRequest req, ServletResponse res)
- throws ServletException, IOException;
- /**
- * Returns information about the servlet, such
- * as author, version, and copyright.
- *
- * <p>The string that this method returns should
- * be plain text and not markup of any kind (such as HTML, XML,
- * etc.).
- *
- * @return a <code>String</code> containing servlet information
- *
- */
- public String getServletInfo();
- /**
- *
- * Called by the servlet container to indicate to a servlet that the
- * servlet is being taken out of service. This method is
- * only called once all threads within the servlet's
- * <code>service</code> method have exited or after a timeout
- * period has passed. After the servlet container calls this
- * method, it will not call the <code>service</code> method again
- * on this servlet.
- *
- * <p>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 void destroy();
- }