【Spring教程23】Spring框架实战：从零开始学习SpringMVC 之 SpringMVC简介与SpringMVC概述

欢迎大家回到《Java教程之Spring30天快速入门》，本教程所有示例均基于Maven实现，如果您对Maven还很陌生，请移步本人的博文《如何在windows11下安装Maven并配置以及 IDEA配置Maven环境》，本文的上一篇为《Spring事务角色与 Spring事务属性、事务传播行为》
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1，SpringMVC简介

从这一节开始，我们开始学习SpringMVC，看到SpringMVC这个名字我们会发现其中包含Spring,那么SpringMVC和Spring之间的会有关系么?答案是肯定有，SpringMVC隶属于Spring，是Spring技术中的一部分。那么SpringMVC到底是用来做什么的呢?

回想web阶段，我们学习过Servlet,而SpringMVC与Servlet技术功能等同，均属于web层或者说表现层开发技术。

那么既然已经有了Servlet为什么还需要花时间再学习一个SpringMVC技术?要回答这个问题，我们
就需要搞清楚SpringMVC与Servlet相比，有什么优势:

框架我们都知道是用来简化开发的，所以SpringMVC与Servlet相比，开发起来更简单快捷，用更少的代码完成表现层代码的开发，那么问题又来了，到底有多简单呢?我们通过一个例子来体验一把吧。

将资料中的项目导入到IDEA中，打开后格式如下
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UserSaveServlet:使用Servlet开发的用户新增模块

@WebServlet("/user/save")
public class UserSaveServlet extends HttpServlet{@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {//1.接收请求参数String name = req.getParameter("name");System.out.println("servlet save name ==> " + name);//2.生产响应resp.setContentType("text/json;charset=utf-8");PrintWriter pw = resp.getWriter();pw.write("{'module':'servlet save'}");}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {this.doGet(req,resp);}
}

UserUpdateServlet:使用Servlet开发的用户修改模块

@WebServlet("/user/update")
public class UserUpdateServlet extends HttpServlet{@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {//1.接收请求参数String name = req.getParameter("name");System.out.println("servlet update name ==> " + name);//2.生产响应resp.setContentType("text/json;charset=utf-8");PrintWriter pw = resp.getWriter();pw.write("{'module':'servlet update'}");
}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {this.doGet(req,resp);}
}

UserDeleteServlet:使用Servlet开发的用户删除模块

@WebServlet("/user/delete")
public class UserDeleteServlet extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {//1.接收请求参数String name = req.getParameter("name");System.out.println("servlet delete name ==> " + name);//2.生产响应resp.setContentType("text/json;charset=utf-8");PrintWriter pw = resp.getWriter();pw.write("{'module':'servlet delete'}");}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {this.doGet(req,resp);}
}

UserSelectServlet:使用Servlet开发的用户查询模块

@WebServlet("/user/select")
public class UserSelectServlet extends HttpServlet{@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {//1.接收请求参数String name = req.getParameter("name");System.out.println("servlet select name ==> " + name);//2.生产响应resp.setContentType("text/json;charset=utf-8");PrintWriter pw = resp.getWriter();pw.write("{'module':'servlet select'}");}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {this.doGet(req,resp);}
}

启动项目，测试结果如下:
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上面就是通过Servlet的方式来实现的用户模块的增删改查功能。那么如果使用SpringMVC来开发相
同的功能，做出来是什么样子的呢?

打开项目springmvc包下的UserController类，内容如下:

@Controller
public class UserController {@RequestMapping("/save")@ResponseBodypublic String save(String name){System.out.println("springmvc save name ==> " + name);return "{'module':'springmvc save'}";}@RequestMapping("/delete")@ResponseBodypublic String delete(String name){System.out.println("springmvc delete name ==> " + name);return "{'module':'springmvc delete'}";}@RequestMapping("/update")@ResponseBodypublic String update(String name){System.out.println("springmvc update name ==> " + name);return "{'module':'springmvc update'}";}@RequestMapping("/select")@ResponseBodypublic String select(String name){System.out.println("springmvc select name ==> " + name);return "{'module':'springmvc select'}";}
}