SpringMVC之简介

news2024/12/23 12:18:51

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:

UserSaveServlet:使用Servlet开发的用户新增模块

@WebServlet("/user/save")
public class UserSaveServlet extends HttpServlet{

    @Override
    protected 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'}");
    }

    @Override
    protected 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{
    @Override
    protected 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'}");
    }

    @Override
    protected 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 {

    @Override
    protected 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'}");
    }

    @Override
    protected 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{

    @Override
    protected 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'}");
    }

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

启动项目，测试结果如下:

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")
    @ResponseBody
    public String save(String name){
        System.out.println("springmvc save name ==> " + name);
        return "{'module':'springmvc save'}";
    }

    @RequestMapping("/delete")
    @ResponseBody
    public String delete(String name){
        System.out.println("springmvc delete name ==> " + name);
        return "{'module':'springmvc delete'}";
    }

    @RequestMapping("/update")
    @ResponseBody
    public String update(String name){
        System.out.println("springmvc update name ==> " + name);
        return "{'module':'springmvc update'}";
    }

    @RequestMapping("/select")
    @ResponseBody
    public String select(String name){
        System.out.println("springmvc select name ==> " + name);
        return "{'module':'springmvc select'}";
    }
}

启动项目，测试结果如下: