Spring MVC请求处理链路核心组件配置指南
项目概述 本文档详细展示一个基于Spring MVC框架的Web应用完整配置流程，重点解析处理器映射器与处理器适配器的工作机制。通过实际代码演示，帮助开发者理解从请求到响应的完整处理链路。
目录结构
springmvc-demo/
├── pom.xml
├── src/
│ └── main/
│ ├── java/
│ │ └── com/
│ │ └── example/
│ │ └── controller/
│ │ └── HomeController.java
│ ├── resources/
│ │ ├── applicationContext.xml
│ │ └── spring-mvc.xml
│ └── webapp/
│ ├── WEB-INF/
│ │ └── web.xml
│ └── WEB-INF/
│ └── views/
│ └── welcome.jsp
Maven依赖配置 pom.xml文件中需要引入Spring MVC、Web及JSP相关依赖包：
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example</groupId>
<artifactId>springmvc-demo</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>war</packaging>
<properties>
<maven.compiler.source>11</maven.compiler.source>
<maven.compiler.target>11</maven.compiler.target>
<spring.version>RELEASE</spring.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>4.0.1</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>javax.servlet.jsp-api</artifactId>
<version>2.3.3</version>
<scope>provided</scope>
</dependency>
</dependencies>
<build>
<finalName>springmvc-demo</finalName>
</build>
</project>
Spring核心容器配置 applicationContext.xml用于配置非Web层的Bean，通常只扫描Service、Repository等组件：
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd">
<context:component-scan base-package="com.example" use-default-filters="true">
<context:exclude-filter type="annotation"
expression="org.springframework.stereotype.Controller"/>
</context:component-scan>
</beans>
Spring MVC配置详解 spring-mvc.xml是Spring MVC的核心配置文件，需要特别注意组件扫描、处理器映射器和适配器的配置：
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc
https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<context:component-scan base-package="com.example" use-default-filters="false">
<context:include-filter type="annotation"
expression="org.springframework.stereotype.Controller"/>
</context:component-scan>
<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping"
id="handlerMapping"/>
<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter"
id="handlerAdapter"/>
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="viewResolver">
<property name="prefix" value="/WEB-INF/views/"/>
<property name="suffix" value=".jsp"/>
</bean>
</beans>
配置说明：
- RequestMappingHandlerMapping：负责将请求URL映射到具体的控制器方法，通过
@RequestMapping注解识别处理方法 - RequestMappingHandlerAdapter：找到对应的处理方法后，负责调用该方法并处理返回值，最终生成ModelAndView
- 上述两个Bean可以简化为
<mvc:annotation-driven/>配置 - InternalResourceViewResolver：视图解析器，用于将逻辑视图名解析为具体的视图页面
控制器实现 HomeController.java展示了基于注解的控制器开发模式：
package com.example.controller;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.servlet.ModelAndView;
@Controller
public class HomeController {
@GetMapping("/index")
public ModelAndView index() {
ModelAndView mav = new ModelAndView("welcome");
mav.addObject("message", "Spring MVC Demo");
return mav;
}
}
该控制器处理/index路径的GET请求，返回名为"welcome"的视图，并在模型中添加"message"属性。
视图页面 welcome.jsp作为视图模板展示数据：
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>欢迎页面</title>
</head>
<body>
<h1>${message}</h1>
</body>
</html>
Web应用部署描述符 web.xml需要分别加载Spring核心容器和Spring MVC容器的配置文件：
<?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_3_1.xsd"
version="3.1">
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:applicationContext.xml</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<servlet>
<servlet-name>dispatcher</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:spring-mvc.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>dispatcher</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
处理流程总结 整个请求处理流程如下：
- 客户端发送请求至
/index - DispatcherServlet拦截请求
- RequestMappingHandlerMapping根据URL查找对应的处理方法
- RequestMappingHandlerAdapter调用具体的控制器方法
- 控制器方法执行并返回ModelAndView对象
- 视图解析器解析视图名称并定位JSP页面
- 渲染页面并返回响应给客户端
简化配置方案
在实际项目中，可以直接使用<mvc:annotation-driven/>替代手动配置处理器映射器和适配器，Spring会自动注册所需的组件：
<beans>
<context:component-scan base-package="com.example" use-default-filters="false">
<context:include-filter type="annotation"
expression="org.springframework.stereotype.Controller"/>
</context:component-scan>
<mvc:annotation-driven/>
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/views/"/>
<property name="suffix" value=".jsp"/>
</bean>
</beans>
