使用 maven 构建 SpringMVC

引言

最近需要使用SpringMVC做一个小项目，之前对SpringMVC没什么了解，所以先写一个SpringMVC的小Demo练习一下。

使用Maven构建项目

IDE = Eclipse

首先创建一个Maven的webapp项目，Jar包的管理就交给Maven来完成；POM内容如下：

<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/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.tuo.example</groupId>
  <artifactId>SpringMVC</artifactId>
  <packaging>war</packaging>
  <version>0.0.1-SNAPSHOT</version>
  <name>SpringMVC Maven Webapp</name>
  <url>http://maven.apache.org</url>
  
  <properties>  
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>  
        <springversion>4.1.2.RELEASE</springversion>  
        <junitversion>3.8.1</junitversion>  
  </properties>  
  
  <dependencies>
  
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
    
    <!-- Spring -->
    <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-aop</artifactId>  
            <version>${springversion}</version>  
            <type>jar</type>  
            <scope>compile</scope>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-aspects</artifactId>  
            <version>${springversion}</version>  
            <type>jar</type>  
            <scope>compile</scope>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-beans</artifactId>  
            <version>${springversion}</version>  
            <type>jar</type>  
            <scope>compile</scope>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-context</artifactId>  
            <version>${springversion}</version>  
            <type>jar</type>  
            <scope>compile</scope>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-context-support</artifactId>  
            <version>${springversion}</version>  
            <type>jar</type>  
            <scope>compile</scope>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-core</artifactId>  
            <version>${springversion}</version>  
            <type>jar</type>  
            <scope>compile</scope>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-expression</artifactId>  
            <version>${springversion}</version>  
            <type>jar</type>  
            <scope>compile</scope>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-jdbc</artifactId>  
            <version>${springversion}</version>  
            <type>jar</type>  
            <scope>compile</scope>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-jms</artifactId>  
            <version>${springversion}</version>  
            <type>jar</type>  
            <scope>compile</scope>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-orm</artifactId>  
            <version>${springversion}</version>  
            <type>jar</type>  
            <scope>compile</scope>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-oxm</artifactId>  
            <version>${springversion}</version>  
            <type>jar</type>  
            <scope>compile</scope>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-tx</artifactId>  
            <version>${springversion}</version>  
            <type>jar</type>  
            <scope>compile</scope>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-web</artifactId>  
            <version>${springversion}</version>  
            <type>jar</type>  
            <scope>compile</scope>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-webmvc</artifactId>  
            <version>${springversion}</version>  
            <type>jar</type>  
            <scope>compile</scope>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-test</artifactId>  
            <version>${springversion}</version>  
            <type>jar</type>  
            <scope>compile</scope>  
        </dependency>  
  
          <!-- servlet & jstl-->
        <dependency>  
            <groupId>javax.servlet</groupId>  
            <artifactId>jstl</artifactId>  
            <version>1.2</version>  
            <type>jar</type>  
            <scope>compile</scope>  
        </dependency>  
  
          <!-- common -->
        <dependency>  
            <groupId>commons-collections</groupId>  
            <artifactId>commons-collections</artifactId>  
            <version>3.1</version>  
        </dependency>  
        <dependency>  
            <groupId>commons-logging</groupId>  
            <artifactId>commons-logging</artifactId>  
            <version>1.1</version>  
        </dependency>  
    
  </dependencies>
  <build>
    <finalName>SpringMVC</finalName>
  </build>
</project>

修改Web.xml配置

web.xml作为前端的配置文件，需要在其中指定以SpringMVC方式处理HTTP请求，即配置servlet标签为SpringMVC，并且指明使用哪个文件作为SpringMVC的配置文件。

<?xml version="1.0" encoding="UTF-8"?>

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>SpringMVC01</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>    
  </welcome-file-list>
  
  <!-- configure springmvc dispatcher for Servlet -->
  <servlet>
      <servlet-name>springmvc</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>
  </servlet>
  <servlet-mapping>
      <servlet-name>springmvc</servlet-name>
      <url-pattern>*.do</url-pattern>
  </servlet-mapping>
</web-app>

SpringMVC 配置文件

如上面web.xml中所示，我这里使用spring-mvc.xml最为SpringMVC的配置文件，并将其放在Maven项目默认的resoucres目录下：

其内容为：

<?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:p="http://www.springframework.org/schema/p"
    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
        http://www.springframework.org/schema/context/spring-context.xsd">

    <!-- 使用注解的包，包括子集 -->
    <context:component-scan base-package="com.example.tuo"/>

    <!-- 视图解析器 -->
    <bean id="viewResolver"
        class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/" />
        <property name="suffix" value=".jsp"></property>
    </bean>

</beans>

到此，SpringMVC的配置部分就完成了；下面需要写 controller 类 以及 HTML和JSP 页面。

实现HTML引导页面

基于我们在web.xml里面里面关于 “servlet-mapping” 的定义，我们需要截获的HTTP request 为 *.do(例如：http://localhost:8080/SpringMVC/HelloSpringMVC.do)

在这里，我们不直接输入xxx.do,通过web.xml里面定义的index.html中的超链接跳转到目标地址（HelloSpringMVC.do）。HTML如下：

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>SpringMVC start page</title>
</head>
<body>
<a href="sayHello.do">Hello springMVC!</a>
</body>
</html>

实现controller类

讲 controller 类放在controller包下，其内容很简单，就是利用MVC中的Model返回一个message到JSP，代码如下

package com.example.tuo.controller;

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

@Controller
public class HelloSpringMVC {

    @RequestMapping("sayHello")
    public void sayHello(Model model){
        model.addAttribute("message", "Hello SpringMVC, I am coming!");
    }
}

实现 JSP 页面

还是基于我们在web.xml里面的视图解析器定义：

<!-- 视图解析器 -->
    <bean id="viewResolver"
        class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/" />
        <property name="suffix" value=".jsp"></property>
    </bean>

我们在项目里面建立一个sayHello.jsp, 请注意这里的前后缀以及在controller类里面定义的@RequestMapping的内容， 把它们连接在一起应指向了JSP页面：prefix+RequestMapping("sayHello")+suffix = /WEB-INF/jsp/sayHello.jsp， 如图所示：

JSP页面本身的内容就很简单了，只是简单的输出在controller类里面定义的message：

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!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=ISO-8859-1">
<title>SpringMVC page</title>
</head>
<body>
${message}  
</body>
</html>

OK，我们的所有编码工作到这里就全部完成。启动Tomcat加载并运行项目，在浏览器中输入导航页面的路径：http://localhost:8080/SpringMVC/后，我们便来到了HTML页面：

在页面上点击超链接，即可跳转到sayHello.jsp；我们可以看到在view中输出了我们在controller里面定义的内容“Hello SpringMVC, I am coming!”;

Well done！我们的SpringMVC项目运行正确啦 :)