第一个servlet实例—

第一个servlet实例——HelloWorld

内容提要：本文以一个“Hello World”的简单例子，开始servlet之旅。

开发环境：eclipse3.5+jdk6.0+tomcat7.0

详细步骤：

1、打开 Eclipse，新建 Dynamic Web Project项目，项目名为test

2、在Java Resources -->src目录新建一个class，文件名为Hello.java，代码如下：

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;


public class Hello extends HttpServlet {

    public Hello() {
        super();
    }

    public void destroy() {
        super.destroy(); 
    }


    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
        out.println("<HTML>");
        out.println("  <HEAD><TITLE>A Servlet</TITLE></HEAD>");
        out.println("  <BODY>");
        out.print("hello world !  This is ");
        out.print(this.getClass());
        out.println(", using the GET method!");
        out.println("</BODY>");
        out.println("</HTML>");
        out.flush();
        out.close();
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
        out.println("<HTML>");
        out.println("  <HEAD><TITLE>A Servlet</TITLE></HEAD>");
        out.println("  <BODY>");
        out.print("  hello world!  This is ");
        out.print(this.getClass());
        out.println(", using the POST method");
        out.println("  </BODY>");
        out.println("</HTML>");
        out.flush();
        out.close();
    }

}

3、在 WEB-INF 目录下，新建一个xml文件，文件名web.xml，代码如下：

<?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" version="2.5">
  <servlet>
    <servlet-name>Hello</servlet-name>
    <servlet-class>Hello</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>Hello</servlet-name>
    <url-pattern>/servlet/Hello</url-pattern>
  </servlet-mapping>

</web-app>

4、启动Tomcat Server，打开浏览器，输入http://localhost:8080/test/servlet/Hello，回车，页面显示如下：