Servlet知识点

2023-08-13 07:54:31

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">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>