Servlet生命周期方法，request.getRequestDispatcher

时间：2022-02-11 16:33:08

1,request.getRequestDispatcher 方法全称javax.servlet.ServletRequest.getRequestDispatcher(String)

2，在web.xml中配置url-mapping的时候，需要以/开头，否则tomcat启动过程报错；

3，servlet先调用构造函数，再调用init方法；

不进行http请求tomcat不会初始化servlet，关闭tomcat的时候会调用destroy()方法；

package com.stono.servlet;

import java.io.IOException;

import javax.servlet.RequestDispatcher;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class TestServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;

    public TestServlet() {

        System.out.println("com.stono.servlet.TestServlet constructor called");

    }

    @Override

    public void init() throws ServletException {

        System.out.println("com.stono.servlet.TestServlet.init() called");

    }

    @Override

    public void destroy() {

        System.out.println("com.stono.servlet.TestServlet.destroy() called");

    }

    @Override

    protected void doGet(HttpServletRequest req, HttpServletResponse resp)

            throws ServletException, IOException {

        RequestDispatcher dispatcher = req.getRequestDispatcher("test2.do");

        dispatcher.forward(req, resp);

    }

    @Override

    protected void doPost(HttpServletRequest req, HttpServletResponse resp)

            throws ServletException, IOException {

    }

}
2015-9-22 8:57:40 org.apache.catalina.core.AprLifecycleListener init

信息: Loaded APR based Apache Tomcat Native library 1.1.24 using APR version 1.4.6.

2015-9-22 8:57:40 org.apache.catalina.core.AprLifecycleListener init

信息: APR capabilities: IPv6 [true], sendfile [true], accept filters [false], random [true].

2015-9-22 8:57:40 org.apache.catalina.core.AprLifecycleListener initializeSSL

信息: OpenSSL successfully initialized (OpenSSL 1.0.1c 10 May 2012)

2015-9-22 8:57:40 org.apache.coyote.AbstractProtocol init

信息: Initializing ProtocolHandler ["http-apr-8080"]

2015-9-22 8:57:40 org.apache.coyote.AbstractProtocol init

信息: Initializing ProtocolHandler ["ajp-apr-8009"]

2015-9-22 8:57:40 org.apache.catalina.startup.Catalina load

信息: Initialization processed in 851 ms

2015-9-22 8:57:40 org.apache.catalina.core.StandardService startInternal

信息: Starting service Catalina

2015-9-22 8:57:40 org.apache.catalina.core.StandardEngine startInternal

信息: Starting Servlet Engine: Apache Tomcat/7.0.35

2015-9-22 8:57:40 org.apache.catalina.startup.HostConfig deployDirectory

信息: Deploying web application directory D:\Java\apache-tomcat-7.0.35\webapps\TestBootWeb

2015-9-22 8:57:41 org.apache.coyote.AbstractProtocol start

信息: Starting ProtocolHandler ["http-apr-8080"]

2015-9-22 8:57:41 org.apache.coyote.AbstractProtocol start

信息: Starting ProtocolHandler ["ajp-apr-8009"]

2015-9-22 8:57:41 org.apache.catalina.startup.Catalina start

信息: Server startup in 322 ms

com.stono.servlet.TestServlet constructor called

com.stono.servlet.TestServlet.init() called

do get method called!

2015-9-22 8:57:47 org.apache.catalina.core.StandardServer await

信息: A valid shutdown command was received via the shutdown port. Stopping the Server instance.

2015-9-22 8:57:47 org.apache.coyote.AbstractProtocol pause

信息: Pausing ProtocolHandler ["http-apr-8080"]

2015-9-22 8:57:47 org.apache.coyote.AbstractProtocol pause

信息: Pausing ProtocolHandler ["ajp-apr-8009"]

2015-9-22 8:57:47 org.apache.catalina.core.StandardService stopInternal

信息: Stopping service Catalina

com.stono.servlet.TestServlet.destroy() called

2015-9-22 8:57:47 org.apache.coyote.AbstractProtocol stop

信息: Stopping ProtocolHandler ["http-apr-8080"]

2015-9-22 8:57:47 org.apache.coyote.AbstractProtocol stop

信息: Stopping ProtocolHandler ["ajp-apr-8009"]

2015-9-22 8:57:47 org.apache.coyote.AbstractProtocol destroy

信息: Destroying ProtocolHandler ["http-apr-8080"]

2015-9-22 8:57:47 org.apache.coyote.AbstractProtocol destroy

信息: Destroying ProtocolHandler ["ajp-apr-8009"]

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