Servlet入门（第一个Servlet的Web程序）

新建maven项目，注意项目的类型

 

 

工程名为ServletExample

 

 

点击Finish，建立maven项目完成如下

 

 

 

生成后的目录没有java源码目录，按照maven的约定，还要新建src/main/java的源码目录。选中项目，点击鼠标右键

 

 

不知道为什么，新建src/main/java目录时，eclipse报这个目录已经存在。没办法，先建立src/main/java2，然后再重构为src/main/java

 

 

 

 

 

配置maven的构建文件pom.xml

xml version="1.0" encoding="UTF-8"?>

xmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

       xsi:schemaLocation="http://maven.apache.org/POM/4.0.0http://maven.apache.org/maven-v4_0_0.xsd">

       4.0.0

       war

       ServletExample

       com.ydoing

       ServletExample

       0.0.1-SNAPSHOT

 

      

             

                   

                           org.apache.maven.plugins

                           maven-compiler-plugin

                           3.1

                          

                                  1.7

                                  1.7

                          

                   

             

      

      

             

                    javax.servlet

                    javax.servlet-api

                    3.0.1

             

      

 

 

更新maven项目

 

新增HelloServlet

 

 

代码如下，该类核心代码是doGet，作用是向客户端返回“Hello, world!”

package com.ydoing.helloapp;

 

import java.io.IOException;

import java.io.PrintWriter;

 

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

 

/**

 * Servletimplementation class HelloServlet

 */

publicclassHelloServletextendsHttpServlet{

       privatestaticfinallongserialVersionUID =1L;

      

    /**

     * @see HttpServlet#HttpServlet()

     */

    publicHelloServlet(){

        super();

        // TODO Auto-generated constructor stub

    }

 

       /**

        * @see HttpServlet#doGet(HttpServletRequestrequest, HttpServletResponse response)

        */

       protectedvoid doGet(HttpServletRequest request,HttpServletResponse response)throwsServletException,IOException{

              // TODO Auto-generated method stub

              response.setContentType("text/html");

              PrintWriter out = response.getWriter();

              String msg ="Hello, world!";

              out.println("

"+ msg +"

");

       }

 

       /**

        * @see HttpServlet#doPost(HttpServletRequestrequest, HttpServletResponse response)

        */

       protectedvoid doPost(HttpServletRequest request,HttpServletResponse response)throwsServletException,IOException{

              // TODO Auto-generated method stub

       }

 

}

 

修改web.xml文件。作用是将URI映射到指定的Servlet上

xml version="1.0" encoding="UTF-8"?>

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

       xmlns="http://java.sun.com/xml/ns/javaee"

       xsi:schemaLocation="http://java.sun.com/xml/ns/javaeehttp://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"

       id="WebApp_ID"version="3.0">

 

      

              HelloServlet

              com.ydoing.helloapp.HelloServlet

      

      

              HelloServlet

              /hello

      

 

 

运行在Tomcat上

 

 

 

运行结果如下