要使用Servlet一定要继承于HttpServlet
HttpHello类，切记要继承HttpServlet
1 import java.io.IOException;
2 import javax.servlet.ServletException;
3 import javax.servlet.http.HttpServlet;
4 import javax.servlet.http.HttpServletRequest;
5 import javax.servlet.http.HttpServletResponse;
6
7 public class HttpHello extends HttpServlet {
8 private static final long serialVersionUID = 1L;
9
10 public HttpHello() {
11 super();
12 }
13
14 protected void doGet(HttpServletRequest request,
15 HttpServletResponse response) throws ServletException, IOException {
16 response.getWriter().write("Hello, world!");
17 }
18
19 protected void doPost(HttpServletRequest request,
20 HttpServletResponse response) throws ServletException, IOException {
21 doGet(request, response);
22 }
23
24 }
然后在\WebContent\WEB-INF 下的Web.xml中进行下面的配置操作（如果没有就自己创建一个）
web.xml
1 <?xml version="1.0" encoding="UTF-8"?>
2 <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">
3 <display-name>DemoWeb</display-name>
4 <welcome-file-list>
5 <welcome-file>index.jsp</welcome-file>
6 </welcome-file-list>
7 <servlet>
8 <servlet-name>HttpHello</servlet-name><!-- 名称起的和类名一样-->
9 <servlet-class>test.HttpHello</servlet-class> <!-- 类所在的路径 -->
10 </servlet>
11 <servlet-mapping>
12 <servlet-name>HttpHello</servlet-name> <!-- 要和上面的名称相同 HttpHello -->
13 <url-pattern>/HttpHello</url-pattern>
14 </servlet-mapping>
15
16 </web-app>
注：生成出来的HttpHello.class文件一定要在\WebContent\WEB-INF \classes文件夹下
tomcat配置正确的情况下。
直接访问 http://localhost:8080/项目名称/HttpHello 就可以看到效果了（本例显示的是Hello!world）