SpringMVC是Spring下的一个模块，与Spring自然无缝衔接，相比Structs2我更喜欢SpringMVC。这篇博客介绍一下SpringMVC的基本工作流程最后会附上一个小demo可供演示。
先上一张图：
这张图展示了SpringMVC大致的工作流程，下面开始逐步讲解：
- 用户通过浏览器发送一个Http给Web应用。
- 如果该请求与web.xml中DisPatcherServlet的配置匹配，则将该请求交由DispatcherServlet处理。
- DispatcherServlet根据请求的信息URL、HTTP处理器等信息以及HandlerMapping的配置找到处理请求的Handler(一般是Controller)。
- 找到Handler后，通过HandlerAdapter对Handler进行封装，使用统一的接口来调用Handler.
- 在Handler完成业务处理之后返回一个ModelAndView给DispatcherServlet,ModelAndView，顾名思义，其中包含一个逻辑视图名和模型数据信息。
- 然后DisPatcherServlet调用ViewResolver完成逻辑视图名到真实的视图对象的解析。
- 当得到真实的视图对象View后，DispatcherServlet会用这个View对ModelAndView中的视图对象进行渲染。
- 最终返回客户端一个Http相应，可能是HTML页面，也可能是一个图片等。
下面做一个demo来实践一下整个过程：
- 先用IDEA创建一个空的的maven工程(也可以new->project->maven->勾选create from archetype->选中webapp，但感觉有问题)。然后按照web应用目录结构手动创建一个webapp及其子目录。
- 在pom.xml中添加依赖，最终结果如下：
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| <?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>SpringMVC-Demo</groupId> <artifactId>springmvc-demo</artifactId> <version>1.0-SNAPSHOT</version> <dependencies> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>4.3.9.RELEASE</version> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>jstl</artifactId> <version>1.2</version> </dependency> </dependencies> <packaging>war</packaging> </project>
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注意要添加jstl依赖，否则会报错。
- 配置web.xml和xxx-servlet.xml文件，配置如下：
web.xml1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39
| <?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"> <display-name>Springmvc-demo</display-name> <servlet> <servlet-name>vzard</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>vzard</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> <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>
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vzard-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" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd"> <context:component-scan base-package="org.vzard.Controller"/> <mvc:default-servlet-handler/> <mvc:annotation-driven/> <bean id="jspViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/> <property name="prefix" value="/WEB-INF/pages/"/> <property name="suffix" value=".jsp"/> </bean> </beans>
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这里要注意的是还要添加一个applicationContext.xml文件，这个文件是Spring的全局配置文件，亲测不配置会报错，里面可以不配置东西，但是这个文件一定要有。
applicationContext.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" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd"> </beans>
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- 然后就是业务逻辑分析部分，这个demo要做的事是：开启应用–>进入欢迎页，点击注册–>进入注册页面，输入信息,点击提交–>进入注册成功页面，显示用户信息
- 业务逻辑实现：
UserController类：1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
| package org.vzard.Controller; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.servlet.ModelAndView; import org.vzard.domain.User; import org.vzard.service.UserService; * Created by V-zar on 2017/8/25. */ @Controller public class UserController { @RequestMapping("/") public String index() { return "index"; } @RequestMapping("/adduser") public String addUser() { return "adduser"; } @RequestMapping(value = "/success") public ModelAndView register(User user) { ModelAndView modelAndView = new ModelAndView(); modelAndView.setViewName("success"); modelAndView.addObject("user", user); return modelAndView; } }
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User类：
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| package org.vzard.domain; * Created by V-zar on 2017/8/25. */ public class User { public String userName; public String password; public String realName; public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getRealName() { return realName; } public void setRealName(String realName) { this.realName = realName; } }
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前端界面引入了Bootstrap（然并卵，还是巨丑，懒得写界面）：
index.jsp
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| <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <!DOCTYPE html> <html lang="zh-CN"> <head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1"> <title>SpringMVC Demo 首页</title> <link rel="stylesheet" href="//cdn.bootcss.com/bootstrap/3.3.5/css/bootstrap.min.css"> <script src="//cdn.bootcss.com/html5shiv/3.7.2/html5shiv.min.js"></script> <script src="//cdn.bootcss.com/respond.js/1.4.2/respond.min.js"></script> <![endif]--> </head> <body> <h1>WELCOME</h1> <form method="post" action="<c:url value="/adduser"/>"> <button class="btn btn-default" type="submit"> <span>注册</span> </button> </form> <script src="//cdn.bootcss.com/jquery/1.11.3/jquery.min.js"></script> <script src="//cdn.bootcss.com/bootstrap/3.3.5/js/bootstrap.min.js"></script> </body> </html>
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adduser.jsp
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| <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <!DOCTYPE html> <html lang="zh-CN"> <head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1"> <title>SpringMVC Demo 首页</title> <link rel="stylesheet" href="//cdn.bootcss.com/bootstrap/3.3.5/css/bootstrap.min.css"> <script src="//cdn.bootcss.com/html5shiv/3.7.2/html5shiv.min.js"></script> <script src="//cdn.bootcss.com/respond.js/1.4.2/respond.min.js"></script> <![endif]--> </head> <body> <form method="post" action="<c:url value="/success"></c:url> "> <div class="input-group"> <span class="input-group-addon">用户名</span> <input type="text" name="userName" class="form-control" aria-label="Amount (to the nearest dollar)"> </div> <div class="input-group"> <span class="input-group-addon">密码</span> <input type="text" name="password" class="form-control" aria-label="Amount (to the nearest dollar)"> </div> <div class="input-group"> <span class="input-group-addon">姓名</span> <input type="text" name="realName" class="form-control" aria-label="Amount (to the nearest dollar)"> </div> <button type="submit" class="btn btn-default" aria-label="Right Align">提交</button> </form> <script src="//cdn.bootcss.com/jquery/1.11.3/jquery.min.js"></script> <script src="//cdn.bootcss.com/bootstrap/3.3.5/js/bootstrap.min.js"></script> </body> </html>
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success.jsp
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| <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <!DOCTYPE html> <html lang="zh-CN"> <head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1"> <title>SpringMVC Demo 首页</title> <link rel="stylesheet" href="//cdn.bootcss.com/bootstrap/3.3.5/css/bootstrap.min.css"> <script src="//cdn.bootcss.com/html5shiv/3.7.2/html5shiv.min.js"></script> <script src="//cdn.bootcss.com/respond.js/1.4.2/respond.min.js"></script> <![endif]--> </head> <body> <h1>欢迎，${user.userName}</h1> <h1>您的密码是：${user.password}</h1> <h1>您的真实姓名是：${user.realName}</h1> <script src="//cdn.bootcss.com/jquery/1.11.3/jquery.min.js"></script> <script src="//cdn.bootcss.com/bootstrap/3.3.5/js/bootstrap.min.js"></script> </body> </html>
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运行结果：
完整demo可在我的github上clone运行：Demo
运行环境&工具：