尚硅谷面试第一季-10SpringMVC的工作流程

目录结构：

关键代码：

web.xml

 <?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">
     <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
     </welcome-file-list>
     <!-- 设置CharacterEncodingFilter -->
     <filter>
         <filter-name>CharacterEncodingFilter</filter-name>
         <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
         <!-- 设置请求的字符集 -->
         <init-param>
             <param-name>encoding</param-name>
             <param-value>UTF-8</param-value>
         </init-param>
         <!-- 设置响应的字符集 -->
         <init-param>
             <param-name>forceEncoding</param-name>
             <param-value>true</param-value>
         </init-param>
     </filter>
     <filter-mapping>
         <filter-name>CharacterEncodingFilter</filter-name>
         <url-pattern>/*</url-pattern>
     </filter-mapping>
     <servlet>
         <servlet-name>springDispatcherServlet</servlet-name>
         <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
         <init-param>
             <param-name>contextConfigLocation</param-name>
             <param-value>WEB-INF/springmvc.xml</param-value>
         </init-param>
         <load-on-startup>1</load-on-startup>
     </servlet>

     <servlet-mapping>
         <servlet-name>springDispatcherServlet</servlet-name>
         <url-pattern>/</url-pattern>
     </servlet-mapping>

     <!-- 注册HiddenHttpMethodFilter，目的是为了将一个POST请求转换为PUT或者DELETE请求 -->
     <filter>
         <filter-name>HiddenHttpMethodFilter</filter-name>
         <filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>
     </filter>
     <filter-mapping>
         <filter-name>HiddenHttpMethodFilter</filter-name>
         <url-pattern>/*</url-pattern>
     </filter-mapping>
 </web-app>

SpringMVCHandler.java

 package SpringMVC的工作流程.handler;

 import java.util.Map;

 import SpringMVC的工作流程.entities.Department;
 import SpringMVC的工作流程.entities.Employee;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.servlet.ModelAndView;

 @Controller
 public class SpringMVCHandler {

     public static final String SUCCESS="success";

     //1.简单的谈一下SpringMVC的工作流程

     //处理模型数据方式一：将方法的返回值设置为ModelAndView
     @RequestMapping("/testModelAndView")
     public ModelAndView testModelAndView() {
         //1.创建ModelAndView对象
         ModelAndView mav = new ModelAndView();
         //2.设置模型数据，最终会放到request域中
         mav.addObject("user", "admin");
         //3.设置视图
         mav.setViewName("success");
         return mav;
     }
     /*
      * ★处理模型数据方式二：方法的返回值仍是String类型，在方法的入参中传入Map、Model或者ModelMap
      *     不管将处理器方法的返回值设置为ModelAndView还是在方法的入参中传入Map、Model或者ModelMap，
      *  SpringMVC都会转换为一个ModelAndView对象
      */
     @RequestMapping("/testMap")
     public String testMap(Map<String , Object> map) {
         //向Map中添加模型数据，最终会自动放到request域中
         map.put("user", new Employee(1, "韩总", "hybing@atguigu.com", new Department(101, "教学部")));
         return SUCCESS;
     }

 }

运行结果：

完整代码：

https://gitee.com/ZhangShunHai/interview_atguigu_seasonone/tree/master/ssm_springmvc%20workflow

课堂重点:

SpringMVC工作流程图：