创建第一个springmvc程序

1、创建父项目文件，导入依赖，删除src文件夹

pom.xml文件

<dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
        <!-- https://mvnrepository.com/artifact/javax.servlet.jsp.jstl/jstl-api -->
        <dependency>
            <groupId>javax.servlet.jsp.jstl</groupId>
            <artifactId>jstl-api</artifactId>
            <version>1.2</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/javax.servlet.jsp/javax.servlet.jsp-api -->
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>javax.servlet.jsp-api</artifactId>
            <version>2.3.3</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.3.20</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.24</version>
        </dependency>
    </dependencies>

2、创建子项目文件，导入jar包

pom.xml

<dependencies>
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>javax.servlet.jsp-api</artifactId>
            <version>2.3.3</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>
    </dependencies>

3、右键子项目文件，添加框架支持，选中web框架

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">
    <!--写死的-->
    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <!--根据classpath创建spring对应的applicationContext.xml文件-->
            <param-value>classpath:springmvc-servlet.xml</param-value>
        </init-param>
        <!--启动级别:1为服务器启动就开启，值越接近1优先级越高-->
        <load-on-startup>1</load-on-startup>
    </servlet>
    <!--在springmvc中,
	/  :会匹配所有请求，除了jsp
	/* :会匹配所有请求，包括jsp，会导致无限循环的hello.jsp.jsp.jsp.....
	-->
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

4、创建applicationContext.xml文件，添加对应bean

<?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">
    
<!--添加spring的BeanNameUrlHandlerMapping、SimpleControllerHandlerAdapter和InternalResourceViewResolver-->
    
    <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">
        <!--根据prefix找到文件夹目录，根据suffix找到对应类型的文件-->
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

    <!--将写好的servlet类加入bean中，id为请求的路径-->
    <bean id="/hello" class="com.kuang.controller.HelloController"/>

</beans>

5、编写bean中对应的servlet类

package com.kuang.controller;

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

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


//实现controller接口，重写handleRequest方法，返回一个视图
public class HelloController implements Controller {
    @Override
    public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception {
        //新建一个modelandview
        ModelAndView mv = new ModelAndView();
        
        //添加对象
        mv.addObject("msg","HelloSpringMVC");
        
        //设置返回的视图，不需要后缀名，在applicationcontext中添加过suffix
        mv.setViewName("hello");
        
        //将对应视图返回
        return mv;
    }
}

6、可能遇到的问题

404找不到文件

不是你代码的问题，可以查看依赖是否成功导入

7、通过tomcat启动运行，在浏览器中访问http://localhost:8080/hello

程序运行成功