The Javaweb Foundation enables servlet classes and servers to start together by configuring Web. Xml

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Javaee:7
javase:1.8
jstl:1.2.2
Server:tomcat 8.5
Explorer:firefox
Os:windows7 x64
Ide:myeclipse

Project directory Structure

Xml

<?xml version= "1.0" encoding= "UTF-8"? ><web-app xmlns:xsi= "Http://www.w3.org/2001/XMLSchema-instance" xmlns= "Http://xmlns.jcp.org/xml/ns/javaee" xsi:schemalocation= "Http://xmlns.jcp.org/xml/ns/javaee/http Xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd "id=" webapp_id "version=" 3.1 "><servlet><servlet-name> specialservletone</servlet-name><servlet-class>jizuiku.web.servlet.specialservletone</ servlet-class><load-on-startup>0</load-on-startup><!--Start the service in a non-negative number from large to small once--></servlet ><servlet-mapping><servlet-name>specialservletone</servlet-name><url-pattern>/ Specialservletone</url-pattern></servlet-mapping><servlet><servlet-name> specialservlettwo</servlet-name><servlet-class>jizuiku.web.servlet.specialservlettwo</ servlet-class><load-on-startup>1</load-on-startup></servlet><servlet-mapping>< Servlet-name>specialservlettwo</servlet-name><url-pattern>/SpecialServletTwo</url-pattern></servlet-mapping><servlet>< servlet-name>commonservlet</servlet-name><servlet-class>jizuiku.web.servlet.commonservlet</ Servlet-class></servlet><servlet-mapping><servlet-name>commonservlet</servlet-name> <url-pattern>/CommonServlet</url-pattern></servlet-mapping></web-app>

Parsing an XML file shows that there are three servlet classes. Where Specialservlettwo, Specialservletone start with the server startup, and Commonservlet is normal, have access to start.

　　
Commonservlet

Package Jizuiku.web.servlet;import Java.io.ioexception;import Javax.servlet.servletexception;import Javax.servlet.http.httpservlet;import Javax.servlet.http.httpservletrequest;import javax.servlet.http.httpservletresponse;/** * * * *  @author to the hardest * @version V17.10.20 */public class Commonservlet Extends HttpServlet {/** *  */private static final long serialversionuid = 1L; @Overridepublic void Init () throws Servle texception {//TODO auto-generated method StubSystem.out.println ("Commonservlet started");} @Overrideprotected void Doget (HttpServletRequest req, HttpServletResponse resp) throws Servletexception, IOException {/ /TODO auto-generated method stub} @Overrideprotected void DoPost (HttpServletRequest req, HttpServletResponse resp) Throws Servletexception, IOException {//TODO auto-generated method stub}}

Specialservletone

Package Jizuiku.web.servlet;import Java.io.ioexception;import Javax.servlet.servletexception;import Javax.servlet.http.httpservlet;import Javax.servlet.http.httpservletrequest;import javax.servlet.http.httpservletresponse;/** * * * *  @author to the hardest * @version V17.10.20 */public class Specialservletone extends HttpServlet {/** *  */private static final long serialversionuid = 1L; @Overridepublic void in It () throws Servletexception {//TODO auto-generated method StubSystem.out.println ("Specialservletone started");} @Overrideprotected void Doget (HttpServletRequest req, HttpServletResponse resp) throws Servletexception, IOException {/ /TODO auto-generated method stub} @Overrideprotected void DoPost (HttpServletRequest req, HttpServletResponse resp) Throws Servletexception, IOException {//TODO auto-generated method stub}}

Specialservlettwo

Package Jizuiku.web.servlet;import Java.io.ioexception;import Javax.servlet.servletexception;import Javax.servlet.http.httpservlet;import Javax.servlet.http.httpservletrequest;import javax.servlet.http.httpservletresponse;/** * * * *  @author to the hardest * @version V17.10.20 */public class Specialservlettwo extends HttpServlet {/** *  */private static final long serialversionuid = 1L; @Overridepublic void in It () throws Servletexception {//TODO auto-generated method StubSystem.out.println ("Specialservlettwo started");} @Overrideprotected void Doget (HttpServletRequest req, HttpServletResponse resp) throws Servletexception, IOException {/ /TODO auto-generated method stub} @Overrideprotected void DoPost (HttpServletRequest req, HttpServletResponse resp) Throws Servletexception, IOException {//TODO auto-generated method stub}}

Part of the console output when the server starts

Info: Starting Servlet engine:apache tomcat/8.5.23 October 20, 2017 9:10:41 pm Org.apache.catalina.startup.HostConfig deploydire Ctory Info: Deploying Web application directory [E:\develop\apache-tomcat-8.5.23\webapps\Day09] October 20, 2017 9:10:41 pm  Org.apache.jasper.servlet.TldScanner Scanjars Info: At least one JAR is scanned for TLDs yet contained no TLDs. Enable Debug Logging for the logger for a complete list of JARs that were scanned and no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time. Specialservletone started Specialservlettwo started October 20, 2017 9:10:41 pm Org.apache.catalina.startup.HostConfig Deploydirectory Info: Deployment of Web application directory [E:\DEVELOP\APACHE-TOMCAT-8.5.23\WEBAPPS\DAY09] has Finished in [729] Ms October 20, 2017 9:10:41 pm org.apache.catalina.startup.HostConfig deploydirectory Info: Deploying Web Applica tion directory [E:\develop\apache-tomcat-8.5.23\webapps\docs] October 20, 2017 9:10:41 pm Org.apache.catalina.startup.HosTconfig deploydirectory Info: Deployment of Web application directory [E:\develop\apache-tomcat-8.5.23\webapps\docs] has Finished in [+] Ms October 20, 2017 9:10:41 pm org.apache.catalina.startup.HostConfig deploydirectory Info: Deploying Web Applicat Ion directory [E:\develop\apache-tomcat-8.5.23\webapps\examples] October 20, 2017 9:10:42 pm Org.apache.catalina.core.ApplicationContext Log Info: contextlistener:contextinitialized () October 20, 2017 9:10:42 pm Org.apache.catalina.core.ApplicationContext Log Info: sessionlistener:contextinitialized () October 20, 2017 9:10:42 pm Org.apache.catalina.startup.HostConfig deploydirectory Info: Deployment of Web application directory [E:\develop\ Apache-tomcat-8.5.23\webapps\examples] have finished in [429] Ms October 20, 2017 9:10:42 pm Org.apache.catalina.startup.HostConfig deploydirectory Info: Deploying Web application directory [E:\develop\ Apache-tomcat-8.5.23\webapps\host-manager] October 20, 2017 9:10:42 pm Org.apache.catalina.startup.HostConfig Deploydirectory Info: Deployment of Web ApplicatIon directory [E:\develop\apache-tomcat-8.5.23\webapps\host-manager] have finished in [$] Ms October 20, 2017 9:10:42 pm Org.apa Che.catalina.startup.HostConfig deploydirectory Info: Deploying Web application directory [E:\develop\ Apache-tomcat-8.5.23\webapps\manager] October 20, 2017 9:10:42 pm Org.apache.catalina.startup.HostConfig deploydirectory Info : Deployment of Web application directory [E:\develop\apache-tomcat-8.5.23\webapps\manager] have finished in [] Ms October 20, 2017 9:10:42 pm Org.apache.catalina.startup.HostConfig deploydirectory Info: Deploying Web application directory [e:\ Develop\apache-tomcat-8.5.23\webapps\root] October 20, 2017 9:10:42 pm Org.apache.catalina.startup.HostConfig Deploydirectory Info: Deployment of Web application directory [E:\develop\apache-tomcat-8.5.23\webapps\ROOT] has finished  In [+] Ms October 20, 2017 9:10:42 pm Org.apache.coyote.AbstractProtocol start Info: Starting Protocolhandler ["http-nio-8081"] bodyguards 20, 2017 9:10:42 pm Org.apache.coyote.AbstractProtocol start info: Starting PROTOCOLHAndler ["ajp-nio-8009"] October 20, 2017 9:10:42 pm Org.apache.catalina.startup.Catalina start info: Server Startup in 1383 MS 

When the browser accesses the Web page for the Commonservlet

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The Javaweb Foundation enables servlet classes and servers to start together by configuring Web. Xml