【Spring教程23】Spring框架實戰：從零開始學習SpringMVC 之 SpringMVC簡介與SpringMVC概述

歡迎大家回到《Java教程之Spring30天快速入門》，本教程所有示例均基于Maven實現，如果您對Maven還很陌生，請移步本人的博文《如何在windows11下安裝Maven并配置以及 IDEA配置Maven環境》，本文的上一篇為《Spring事務角色與 Spring事務屬性、事務傳播行為》
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1，SpringMVC簡介

從這一節開始，我們開始學習SpringMVC，看到SpringMVC這個名字我們會發現其中包含Spring,那么SpringMVC和Spring之間的會有關系么?答案是肯定有，SpringMVC隸屬于Spring，是Spring技術中的一部分。那么SpringMVC到底是用來做什么的呢?

回想web階段，我們學習過Servlet,而SpringMVC與Servlet技術功能等同，均屬于web層或者說表現層開發技術。

那么既然已經有了Servlet為什么還需要花時間再學習一個SpringMVC技術?要回答這個問題，我們
就需要搞清楚SpringMVC與Servlet相比，有什么優勢:

框架我們都知道是用來簡化開發的，所以SpringMVC與Servlet相比，開發起來更簡單快捷，用更少的代碼完成表現層代碼的開發，那么問題又來了，到底有多簡單呢?我們通過一個例子來體驗一把吧。

將資料中的項目導入到IDEA中，打開后格式如下
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UserSaveServlet:使用Servlet開發的用戶新增模塊

@WebServlet("/user/save")
public class UserSaveServlet extends HttpServlet{@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {//1.接收請求參數String name = req.getParameter("name");System.out.println("servlet save name ==> " + name);//2.生產響應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開發的用戶修改模塊

@WebServlet("/user/update")
public class UserUpdateServlet extends HttpServlet{@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {//1.接收請求參數String name = req.getParameter("name");System.out.println("servlet update name ==> " + name);//2.生產響應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開發的用戶刪除模塊

@WebServlet("/user/delete")
public class UserDeleteServlet extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {//1.接收請求參數String name = req.getParameter("name");System.out.println("servlet delete name ==> " + name);//2.生產響應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開發的用戶查詢模塊

@WebServlet("/user/select")
public class UserSelectServlet extends HttpServlet{@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {//1.接收請求參數String name = req.getParameter("name");System.out.println("servlet select name ==> " + name);//2.生產響應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);}
}

啟動項目，測試結果如下:
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上面就是通過Servlet的方式來實現的用戶模塊的增刪改查功能。那么如果使用SpringMVC來開發相
同的功能，做出來是什么樣子的呢?

打開項目springmvc包下的UserController類，內容如下:

@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'}";}
}