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SpringMVC工作流程和Demo示例

SpringMVC工作流程和Demo示例

作者: vzardlloo | 来源:发表于2017-08-25 20:10 被阅读836次

    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:

    1. 用户通过浏览器发送一个Http给Web应用。
    2. 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。
    3. 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)。
    4. 找到Handler后,通过HandlerAdapter对Handler进行封装,使用统一的接口来调用Handler.
    5. 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。
    6. 然后DisPatcherServlet调用ViewResolver完成逻辑视图名到真实的视图对象的解析。
    7. 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。
    8. 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:
    <?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>
    
    

    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.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_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>
        <!--解决中文post乱码-->
        <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>
    

    vzard-servlet.xml

    <?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">
    
        <!--指明 controller 所在包,并扫描其中的注解-->
        <context:component-scan base-package="org.vzard.Controller"/>
    
        <!-- 静态资源(js、image等)的访问 -->
        <mvc:default-servlet-handler/>
    
        <!-- 开启注解 -->
        <mvc:annotation-driven/>
    
        <!--ViewResolver 视图解析器-->
        <!--用于支持Servlet、JSP视图解析-->
        <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>
    

    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

    <?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>
    
    • 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:
    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 {
        // @Autowired(required = false)
        //UserService userService;
    
        @RequestMapping("/")
        public String index() {
            return "index";
        }
    
        @RequestMapping("/adduser")
        public String addUser() {
            return "adduser";
        }
    
    
        @RequestMapping(value = "/success")
        public ModelAndView register(User user) {
            //userService.creatUser(user);
            ModelAndView modelAndView = new ModelAndView();
            modelAndView.setViewName("success");
            modelAndView.addObject("user", user);
            return modelAndView;
        }
    
    }
    
    

    User类:

    
    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;
        }
    }
    
    

    前端界面引入了Bootstrap(然并卵,还是巨丑,懒得写界面):
    index.jsp

    <%@ 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">
        <!-- 上述3个meta标签*必须*放在最前面,任何其他内容都*必须*跟随其后! -->
        <title>SpringMVC Demo 首页</title>
    
        <!-- 新 Bootstrap 核心 CSS 文件 -->
        <link rel="stylesheet" href="//cdn.bootcss.com/bootstrap/3.3.5/css/bootstrap.min.css">
    
        <!-- HTML5 shim and Respond.js for IE8 support of HTML5 elements and media queries -->
        <!-- WARNING: Respond.js doesn't work if you view the page via file:// -->
        <!--[if lt IE 9]>
        <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>
    
    <!-- jQuery文件。务必在bootstrap.min.js 之前引入 -->
    <script src="//cdn.bootcss.com/jquery/1.11.3/jquery.min.js"></script>
    
    <!-- 最新的 Bootstrap 核心 JavaScript 文件 -->
    <script src="//cdn.bootcss.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>
    </body>
    </html>
    

    adduser.jsp

    <%@ 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">
        <!-- 上述3个meta标签*必须*放在最前面,任何其他内容都*必须*跟随其后! -->
        <title>SpringMVC Demo 首页</title>
    
        <!-- 新 Bootstrap 核心 CSS 文件 -->
        <link rel="stylesheet" href="//cdn.bootcss.com/bootstrap/3.3.5/css/bootstrap.min.css">
    
        <!-- HTML5 shim and Respond.js for IE8 support of HTML5 elements and media queries -->
        <!-- WARNING: Respond.js doesn't work if you view the page via file:// -->
        <!--[if lt IE 9]>
        <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>
    <!-- jQuery文件。务必在bootstrap.min.js 之前引入 -->
    <script src="//cdn.bootcss.com/jquery/1.11.3/jquery.min.js"></script>
    
    <!-- 最新的 Bootstrap 核心 JavaScript 文件 -->
    <script src="//cdn.bootcss.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>
    </body>
    </html>
    

    success.jsp

    <%@ 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">
        <!-- 上述3个meta标签*必须*放在最前面,任何其他内容都*必须*跟随其后! -->
        <title>SpringMVC Demo 首页</title>
    
        <!-- 新 Bootstrap 核心 CSS 文件 -->
        <link rel="stylesheet" href="//cdn.bootcss.com/bootstrap/3.3.5/css/bootstrap.min.css">
    
        <!-- HTML5 shim and Respond.js for IE8 support of HTML5 elements and media queries -->
        <!-- WARNING: Respond.js doesn't work if you view the page via file:// -->
        <!--[if lt IE 9]>
        <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>
    
    <!-- jQuery文件。务必在bootstrap.min.js 之前引入 -->
    <script src="//cdn.bootcss.com/jquery/1.11.3/jquery.min.js"></script>
    
    <!-- 最新的 Bootstrap 核心 JavaScript 文件 -->
    <script src="//cdn.bootcss.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>
    </body>
    </html>
    

    运行结果:


    完整demo可在我的github上clone运行:Demo
    运行环境&工具:

    • IDEA
    • JDK 1.8
    • Tomcat 8.5

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