SpringMVC-lesson02-hellospringmvc-2023-03-21-526互联

参考网页：https://www.kuangstudy.com/bbs/1618521039124783105

第1步:注册web.xml，注册DispatcherServlet

<?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">

        <!--1.注册DispatcherServlet-->
        <servlet>
            <servlet-name>springmvc</servlet-name>
            <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
            <!--关联一个springmvc的配置文件:[servlet-name]-servlet.xml-->
            <init-param>
                <param-name>contextConfigLocation</param-name>
                <param-value>classpath:springmvc-servlet.xml</param-value>
            </init-param>
            <!--启动级别-1-->
            <load-on-startup>1</load-on-startup>
        </servlet>
        <!--
            在SpringMVC中，    /   /*
            / : 只匹配所有的请求，不会去匹配jsp页面
            /* : 匹配所有的请求，包括jsp页面
        -->
        <servlet-mapping>
            <servlet-name>springmvc</servlet-name>
            <url-pattern>/</url-pattern>
        </servlet-mapping>

    </web-app>

第2步，在resources文件下写一个springmvc-servlet.xml 并添加3个：添加处理器映射器 (HandlerMapping)，添加处理器适配器 (HandlerAdapter) 添加视图解析器 (ViewResolver)

<?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
        http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/>
    <bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter"/>

    <!--视图解析器:DispatcherServlet给他的ModelAndView-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="InternalResourceViewResolver">
        <!--前缀-->
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <!--后缀-->
        <property name="suffix" value=".jsp"/>
    </bean>

    <!--Handler-->
    <bean id="/hello" class="com.feijian.controller.HelloController"/>
</beans>

第3步编写我们要操作业务HelloController类，实现Controller接口，要么增加注解；需要返回一个ModelAndView，装数据，封视图；

package com.feijian.controller;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//注意：这里我们先导入Controller接口
public class HelloController implements Controller {
    public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception {
        //ModelAndView 模型和视图
        ModelAndView mv = new ModelAndView();
        //封装对象，放在ModelAndView中。Model
        mv.addObject("msg","HelloSpringMVC!");
        //封装要跳转的视图，放在ModelAndView中
        mv.setViewName("hello"); //: /WEB-INF/jsp/hello.jsp
        return mv;
    }
}

第4步，将HelloController 注册到Springmvc-servlet.xml中

<!--Handler-->
<bean id="/hello" class="com.feijian.controller.HelloController"/>

写要跳转的jsp页面，显示ModelandView存放的数据，以及我们的正常页面；在WEB-INF文件夹下新建jsp文件夹，新建hello.jsp, 输入￥{msg}

<%--
  Created by IntelliJ IDEA.
  User: Administrator
  Date: 2023/3/21
  Time: 20:11
  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>

    ${msg}

</body>
</html>

配置Tomcat

访问出现404，排查步骤：