創建第一個springmvc程式

1、創建父專案檔案，匯入依賴，洗掉src檔案夾

pom.xml檔案

<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、創建子專案檔案，匯入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、右鍵子專案檔案，添加框架支持，選中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">
    <!--寫死的-->
    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <!--根據classpath創建spring對應的applicationContext.xml檔案-->
            <param-value>classpath:springmvc-servlet.xml</param-value>
        </init-param>
        <!--啟動級別:1為服務器啟動就開啟，值越接近1優先級越高-->
        <load-on-startup>1</load-on-startup>
    </servlet>
    <!--在springmvc中,
	/  :會匹配所有請求，除了jsp
	/* :會匹配所有請求，包括jsp，會導致無限回圈的hello.jsp.jsp.jsp.....
	-->
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

4、創建applicationContext.xml檔案，添加對應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 />
    <bean />
    <bean  id="internalResourceViewResolver">
        <!--根據prefix找到檔案夾目錄，根據suffix找到對應型別的檔案-->
        <property name="prefix" value="https://www.cnblogs.com/WEB-INF/jsp/"/>
        <property name="suffix" value="https://www.cnblogs.com/nhgtx/archive/2022/11/18/.jsp"/>
    </bean>

    <!--將寫好的servlet類加入bean中，id為請求的路徑-->
    <bean id="/hello" />

</beans>

5、撰寫bean中對應的servlet類

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;


//實作controller介面，重寫handleRequest方法，回傳一個視圖
public class HelloController implements Controller {
    @Override
    public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception {
        //新建一個modelandview
        ModelAndView mv = new ModelAndView();
        
        //添加物件
        mv.addObject("msg","HelloSpringMVC");
        
        //設定回傳的視圖，不需要后綴名，在applicationcontext中添加過suffix
        mv.setViewName("hello");
        
        //將對應視圖回傳
        return mv;
    }
}

6、可能遇到的問題

404找不到檔案

不是你代碼的問題，可以查看依賴是否成功匯入

7、通過tomcat啟動運行，在瀏覽器中訪問http://localhost:8080/hello

程式運行成功

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