基于 Maven 的 Web 项目搭建 - 引入 Spring MVC

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搭建 Spring MVC 框架，上接《基于 Maven 的 Web 项目搭建》

引入 Spring MVC 包

在 Maven 的pom.xml中，添加如下代码

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<properties>
    <springVersion>4.3.7.RELEASE</springVersion>
</properties>

<dependencies>
    <!-- Servlet -->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>jstl</artifactId>
        <version>1.2</version>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>3.1.0</version>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>javax.servlet.jsp</groupId>
        <artifactId>jsp-api</artifactId>
        <version>2.2</version>
        <scope>compile</scope>
    </dependency>

    <!-- Spring -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-core</artifactId>
        <version>${springVersion}</version>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-beans</artifactId>
        <version>${springVersion}</version>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>${springVersion}</version>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context-support</artifactId>
        <version>${springVersion}</version>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-orm</artifactId>
        <version>${springVersion}</version>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jdbc</artifactId>
        <version>${springVersion}</version>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jms</artifactId>
        <version>${springVersion}</version>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-tx</artifactId>
        <version>${springVersion}</version>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>${springVersion}</version>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-test</artifactId>
        <version>${springVersion}</version>
        <scope>compile</scope>
    </dependency>
</dependencies>

配置 Web.xml

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<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://xmlns.jcp.org/xml/ns/javaee"
    xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
    id="WebApp_ID" version="3.1">

    <display-name>Simple Demo</display-name>

    <!-- Spring MVC -->
    <servlet>
        <servlet-name>spring</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:config/spring/spring-servlet.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>spring</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

    <!-- 编码过滤 -->
    <filter>
        <filter-name>encodingFilter</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
        <init-param>
            <param-name>forceEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>encodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

</web-app>

新建目录

  • /WEB-INF/下，新建 assets 作为静态资源目录
  • /WEB-INF/下，新建 views 作为页面目录
  • src/main/resources/，新建 config/spring 作为 Spring 的配置文件目录

配置 Servlet

在 src/main/resources/config/spring 中，新建 spring-servlet.xml

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<?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" xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="
       http://www.springframework.org/schema/beans 
       http://www.springframework.org/schema/beans/spring-beans-4.3.xsd 
       http://www.springframework.org/schema/context 
       http://www.springframework.org/schema/context/spring-context-4.3.xsd 
       http://www.springframework.org/schema/mvc 
       http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd">

    <!-- 对静态资源文件的访问 -->
    <mvc:resources mapping="/assets/**" location="/WEB-INF/assets/" />

    <!-- 启用 spring mvc 注解 -->
    <mvc:annotation-driven />

    <!-- 设置使用注解的类所在的jar包 -->
    <context:component-scan base-package="xyz.demo.*"></context:component-scan>

    <!-- 完成请求和注解POJO的映射 -->
    <bean
        class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />

    <!-- 视图层配置 -->
    <bean
        class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/views/" />
        <property name="suffix" value=".jsp" />
    </bean>
</beans>

测试

通过写一个首页访问，测试是否配置成功

  1. src/main/java，新建包xyz.demo.home.controller，新建类HomeController
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package xyz.demo.home.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
@RequestMapping(value = "/home")
public class HomeController {

    @RequestMapping(value = "/index", method = RequestMethod.GET)
    public String hello(Model model) {
        model.addAttribute("msg", "This is Spring MVC");
        
        return "index";
    }

}
  1. src/main/webapp/WEB-INF/views，新建文件index.jsp
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<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>hello</title>
</head>
<body>
    <p>${ msg }</p>
</body>
</html>
  1. 启动 Tomcat 服务，访问http://localhost:8080/simpleDemo/home/index
    Spring Test

后记

请求处理流程简单描述

  1. 请求http://localhost:8080/simpleDemo/home/index
  2. 被web.xml中配置的org.springframework.web.servlet.DispatcherServlet拦截
  3. 解析请求地址home/index
  4. 通过HandlerMapping找到HomeController类的映射（@RequestMapping(value = "/home")），再找到home方法的映射（@RequestMapping(value = "/index", method = RequestMethod.GET)）
  5. 调用home方法后，根据返回类型（String）和返回值（return "index";），通过spring-servlet.xml中配置的org.springframework.web.servlet.view.InternalResourceViewResolver，在/WEB-INF/views/中，找到index.jsp，渲染视图
  6. 返回给浏览器

Spring MVC 最少引入包

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spring-web-4.x.x.RELEASE.jar
spring-beans-4.x.x.RELEASE.jar
spring-context-4.x.x.RELEASE.jar
spring-core-4.x.x.RELEASE.jar
commons-logging-1.1.3.jar
spring-webmvc-4.x.x.RELEASE.jar
spring-aop-4.x.x.RELEASE.jar
spring-expression-4.x.x.RELEASE.jar

参考资料