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：