Servlet知识点

如果请求采用Get方式，则重写doGet()方法，如果请求采用Post方式，则重写doPost()方法。

下面是重写doGet()方法的servlet例子。

servlet继承如下类：

整体结构：

在servlet程序的空白处右键-Source-Override/Implements Methods..，选择重写doGet()与doPost()方法，点击ok，则会自动添加程序段。

由于采用doGet()方式请求Servlet，所以重写doGet()方法，内容如下：

 <%@ page language="java" contentType="text/html; charset=utf-8"
     pageEncoding="utf-8"%>
 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 <html>
 <head>
 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
 <title>第一个Servlet小例子</title>
 </head>
 <body>
 <!-- 超链接就是一种Get请求方式 -->
     <a href="servlet/HelloServlet" rel="external nofollow" >Get方式请求HelloServlet</a>
 </body>
 </html>

index.jsp

 package servlet; 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; //继承于HttpServlet
 public class HelloServlet extends HttpServlet {     @Override
     protected void doGet(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {
         // TODO Auto-generated method stub
         //super.doGet(request, response);
         System.out.println("处理Get()请求");//后台输入话，表名确实进行了对Get()请求的处理
         PrintWriter out =response.getWriter();//打印输出内容
         response.setContentType("text/html;charset=utf-8");//响应内容类型的字符集设置
         out.println("<strong>Hello Servlet</strong><hr>");
     }
     @Override
     protected void doPost(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {
         // TODO Auto-generated method stub
         //super.doPost(request, response);
     } }

HelloServlet.java

 <?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">
   <display-name>MyFirstServlet</display-name>
   <welcome-file-list>
     <welcome-file>index.html</welcome-file>
     <welcome-file>index.htm</welcome-file>
     <welcome-file>index.jsp</welcome-file>
     <welcome-file>default.html</welcome-file>
     <welcome-file>default.htm</welcome-file>
     <welcome-file>default.jsp</welcome-file>
   </welcome-file-list>
   <servlet>
       <servlet-name>HelloServlet01</servlet-name>
       <servlet-class>servlet.HelloServlet</servlet-class>
   </servlet>
   <servlet-mapping>
       <servlet-name>HelloServlet01</servlet-name>
       <!-- url-pattern要和请求的路径相同 -->
       <url-pattern>/servlet/HelloServlet</url-pattern>
   </servlet-mapping>
 </web-app>