搭建mvc环境

视频链接：https://www.bilibili.com/video/BV1aE41167Tu?p=3&spm_id_from=pageDriver

1.4、回顾Servlet
新建一个Maven工程当做父工程！pom依赖！

<dependencies>
   <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>
       <version>4.12</version>
   </dependency>
   <dependency>
       <groupId>org.springframework</groupId>
       <artifactId>spring-webmvc</artifactId>
       <version>5.1.9.RELEASE</version>
   </dependency>
   <dependency>
       <groupId>javax.servlet</groupId>
       <artifactId>servlet-api</artifactId>
       <version>2.5</version>
   </dependency>
   <dependency>
       <groupId>javax.servlet.jsp</groupId>
       <artifactId>jsp-api</artifactId>
       <version>2.2</version>
   </dependency>
   <dependency>
       <groupId>javax.servlet</groupId>
       <artifactId>jstl</artifactId>
       <version>1.2</version>
   </dependency>
</dependencies>

2 建立一个Moudle：springmvc-01-servlet ，添加Web app的支持！导入servlet 和 jsp 的 jar 依赖

<dependency>
   <groupId>javax.servlet</groupId>
   <artifactId>servlet-api</artifactId>
   <version>2.5</version>
</dependency>
<dependency>
   <groupId>javax.servlet.jsp</groupId>
   <artifactId>jsp-api</artifactId>
   <version>2.2</version>
</dependency>

3.编写一个Servlet类，用来处理用户的请求

package com.kuang.servlet;

//实现Servlet接口
public class HelloServlet extends HttpServlet {
    
    
   @Override
   protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    
    
       //取得参数
       String method = req.getParameter("method");
       if (method.equals("add")){
    
    
           req.getSession().setAttribute("msg","执行了add方法");
      }
       if (method.equals("delete")){
    
    
           req.getSession().setAttribute("msg","执行了delete方法");
      }
       //业务逻辑
       //视图跳转
       req.getRequestDispatcher("/WEB-INF/jsp/hello.jsp").forward(req,resp);
  }

   @Override
   protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    
    
       doGet(req,resp);
  }
}

4.编写Hello.jsp，在WEB-INF目录下新建一个jsp的文件夹，新建hello.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
   <title>Kuangshen</title>
</head>
<body>
${
    
    msg}
</body>
</html>

5.在web.xml中注册Servlet

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
        version="4.0">
   <servlet>
       <servlet-name>HelloServlet</servlet-name>
       <servlet-class>com.kuang.servlet.HelloServlet</servlet-class>
   </servlet>
   <servlet-mapping>
       <servlet-name>HelloServlet</servlet-name>
       <url-pattern>/user</url-pattern>
   </servlet-mapping>
 </web-app>

6.配置Tomcat，并启动测试

localhost:8080/user?method=add

localhost:8080/user?method=delete

7.常见错误

https://blog.csdn.net/qq_44543774/article/details/121037134?spm=1001.2014.3001.5501
常见错误