servlet、filter 顺序

java代码：

package com.servlet;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class HelloServlet extends HttpServlet {private static final long serialVersionUID = 1L;public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doPost(request, response);}public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {System.out.println("HelloServlet");}}

package com.filter;import java.io.IOException;import javax.servlet.Filter;import javax.servlet.FilterChain;import javax.servlet.FilterConfig;import javax.servlet.ServletException;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;public class HelloFilter implements Filter {public void destroy() {System.out.println("HelloFilter.destroy");}public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {System.out.println("HelloFilter.doFilter before");chain.doFilter(request, response);System.out.println("HelloFilter.doFilter after");}public void init(FilterConfig fConfig) throws ServletException {System.out.println("HelloFilter.init");}}

web.xml：

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"id="WebApp_ID" version="2.5"><display-name>servlet-filter</display-name><welcome-file-list><welcome-file>HelloServlet</welcome-file></welcome-file-list><servlet><description></description><display-name>HelloServlet</display-name><servlet-name>HelloServlet</servlet-name><servlet-class>com.servlet.HelloServlet</servlet-class></servlet><servlet-mapping><servlet-name>HelloServlet</servlet-name><url-pattern>/HelloServlet</url-pattern></servlet-mapping><filter><display-name>HelloFilter</display-name><filter-name>HelloFilter</filter-name><filter-class>com.filter.HelloFilter</filter-class></filter><filter-mapping><filter-name>HelloFilter</filter-name><url-pattern>/*</url-pattern></filter-mapping></web-app>

输出：

2014-5-5 22:38:09 org.apache.catalina.core.AprLifecycleListener init信息: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: C:\Program Files\Java\jdk1.6.0_05\bin;.;C:\WINDOWS\Sun\Java\bin;C:\WINDOWS\system32;C:\WINDOWS;C:/Program Files/Java/jdk1.6.0_05/bin/../jre/bin/client;C:/Program Files/Java/jdk1.6.0_05/bin/../jre/bin;C:/Program Files/Java/jdk1.6.0_05/bin/../jre/lib/i386;F:\software\apache-maven\apache-maven-3.2.1\bin;C:\Program Files\Java\jdk1.6.0_05\bin;C:\Program Files\Java\jdk1.6.0_05\jre\bin;C:\oracle\product\10.2.0\db_1\bin;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\Program Files\Rational\common;F:\software\java\eclipse-jee-juno-SR2-win32\eclipse;2014-5-5 22:38:09 org.apache.tomcat.util.digester.SetPropertiesRule begin警告: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property 'source' to 'org.eclipse.jst.jee.server:servlet-filter' did not find a matching property.2014-5-5 22:38:10 org.apache.coyote.http11.Http11Protocol init信息: Initializing Coyote HTTP/1.1 on http-80802014-5-5 22:38:10 org.apache.catalina.startup.Catalina load信息: Initialization processed in 601 ms2014-5-5 22:38:10 org.apache.catalina.core.StandardService start信息: Starting service Catalina2014-5-5 22:38:10 org.apache.catalina.core.StandardEngine start信息: Starting Servlet Engine: Apache Tomcat/6.0.29HelloFilter.init2014-5-5 22:38:10 org.apache.coyote.http11.Http11Protocol start信息: Starting Coyote HTTP/1.1 on http-80802014-5-5 22:38:10 org.apache.jk.common.ChannelSocket init信息: JK: ajp13 listening on /0.0.0.0:80092014-5-5 22:38:10 org.apache.jk.server.JkMain start信息: Jk running ID=0 time=0/47  config=null2014-5-5 22:38:10 org.apache.catalina.startup.Catalina start信息: Server startup in 494 msHelloFilter.doFilter beforeHelloServletHelloFilter.doFilter after

看到：

HelloFilter.doFilter before
HelloServlet
HelloFilter.doFilter after