SpringMVC框架的基础

首先：配置springMVC最主要的都是它的配置文件，所以从简单的配置文件演示

SpringMVC.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans
       xmlns="http://www.springframework.org/schema/beans"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="
       http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/mvc
       http://www.springframework.org/schema/mvc/spring-mvc.xsd
">
    <!--开启SpringMVC注解驱动
        其可以代替HandleMapping和HandleAdapter
        如果去掉注解驱动，那么就无法加载HandleMapping与HandleAdapter那么无论是哪种方式都会是404异常
    -->
    <mvc:annotation-driven></mvc:annotation-driven>

　　<!--如果不是注解方式实现，那么就需要自己指定自己配置自己的Controller的访问路径-->

　　<bean name="/*.do" class="com.sxt.controller.NumController"/>

<!--
        加载注解扫描的包。
    -->
    <context:component-scan base-package="com.sxt.controller"/>
　　
    <!--静态资源的放行
        由于web.xml文件中配置路径和tomcat中的路径重叠
            所以在这里配置静态资源的放行，让其不用加载到DispatcherServlet
        mapping:页面请求的时候的路径。
        location：表示本地，如果本地没有这个路劲会报错哦
    -->

    <mvc:resources mapping="/js/**" location="/js/"/>

</beans>

 

 

---

 

 第二点：springMVC的控制器：

方式一：注解方式：

@Controller
public class NumController {

    @RequestMapping("/add")
    public ModelAndView getAddNum(Integer num1, Integer num2){
        System.out.println(num1+"-----------"+num2);
        ModelAndView modelAndView = new ModelAndView();

        modelAndView.addObject("c",(num1+num2));
        modelAndView.setViewName("index.jsp");
        return modelAndView;
    }


}

方式二：实现接口Controller：

package com.sxt.controller;


import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @program:
 * @description:
 * @author: Mr.Zhang
 * @create: 2021-09-23 11:12
 **/
public class NumController implements Controller {

    @Override
    public ModelAndView handleRequest(
            HttpServletRequest req,
            HttpServletResponse resp) throws Exception {

        String num1 = req.getParameter("num1");
        String num2 = req.getParameter("num2");
        System.out.println(num1+"-----------"+num2);
        Integer result = Integer.parseInt(num1)+Integer.parseInt(num2);

        ModelAndView mav = new ModelAndView();
        mav.setViewName("index.jsp");
        mav.addObject("c",result);
        return mav;
    }
}

方式三：实现自HHttpRequestHandler

package com.sxt.controller;


import org.springframework.web.HttpRequestHandler;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * @program:
 * @description:SpringMVC第三种实现方式
 * @author: Mr.Zhang
 * @create: 2021-09-23 11:12
 **/
public class NumController implements HttpRequestHandler {


    @Override
    public void handleRequest(
            HttpServletRequest req,
            HttpServletResponse resp) throws ServletException, IOException {

        String num1 = req.getParameter("num1");
        String num2 = req.getParameter("num2");
        System.out.println(num1+"-----------"+num2);
        Integer result = Integer.parseInt(num1)+Integer.parseInt(num2);

        req.setAttribute("c",result);

        req.getRequestDispatcher("index.jsp").forward(req,resp);
    }
}

 

 

---

 

 Web.xml加载SpringMVC容器

 

<?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">
    <!--
        加载SpringMVC中的Controller配置
    -->
    <servlet>
        <servlet-name>springMVC</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <!--给DispatcherServlet的父类FrameworkServlet的属性赋值，让其加载spring配置文件-->
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:spring.xml</param-value>
        </init-param>
        <!--
            设置其初始化方法在Tomcat启动的时候自动加载，
            如果是0那么就会在第一次发送请求的时候调用初始化方法init(config)
        -->
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>springMVC</servlet-name>
        <!--这么设置和Tomcat里面的配置路劲一样，所以会覆盖掉原有的servlet路径请求
            但是这个DispatcherServlet是不会加载静态的js下包的，所以需要在Spring配置文件设置
            一个直接放行的路径。
        -->
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

 

 

---

 

 jsp前端：

 

<%--
  Created by IntelliJ IDEA.
  User: 86183
  Date: 2021/9/23
  Time: 11:08
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
  <head>
    <title>$Title$</title>
  </head>
  <body>
  <form action="add.do" method="post">
  num1:<input type="text" name="num1" ><br>
  num1:<input type="text" name="num2" ><br>
    <input type="submit" value="提交">
  </br>
  </form>
  <hr>
  <div>C:${c}</div>
  </body>
</html>