SpringMVC执行原理分析

步骤：

  1. 配置文件获得springmvc的核心；DispatcherServlet;
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<?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>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:SpringMVC-servlet.xml</param-value>
        </init-param>
    </servlet>
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

关于 /里面参数的问题：

里面写==/==就只会匹配请求，不会匹配我们的JSP,这样可以避免一些重复的定向；所以这里不要写==/*==

2.配置springMVC-servlet.xml

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<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd">
    <!-- more bean definitions go here -->
    <bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/>
    <bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter"/>
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
        <property name="prefix" value="/JSP/"/>
        <property name="suffix" value=".jsp"/>
    </bean>
    <bean id="/hello" class="com.saxon.controller.MyController"/>
</beans>

配置一个映射器和适配器，用于适配处理controller；

还有一个就是我们的Resolver 这个用于跳转；前缀和后缀；

3.编写controller

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package com.saxon.controller;

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

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

public class MyController implements Controller {
    @Override
    public ModelAndView handleRequest (HttpServletRequest request, HttpServletResponse response) throws Exception {
        ModelAndView modelAndView = new ModelAndView ();
      //业务代码***************
      
      
      //**********************
      //prefix+viewName+suffix:一起构成我们的转发页面
        modelAndView.setViewName ("Hello");//转发的名字

        return modelAndView;
    }
}