使用Maven创建Web应用程序项目

在本教程中，我们将演示如何使用 Maven 创建一个 Java Web 项目(Spring MVC)。

用到的技术/工具：

Maven 3.3.3
Eclipse 4.3
JDK 8
Spring 4.1.1.RELEASED
Tomcat 7
Logback 1.0.13

1. 从Maven模板创建Web项目

您可以通过使用Maven的maven-archetype-webapp模板来创建一个快速启动Java Web应用程序的项目。在终端(* UNIX或Mac)或命令提示符(Windows)中，导航至您想要创建项目的文件夹。

键入以下命令：

$ mvn archetype:generate -DgroupId=com.yiibai -DartifactId=CounterWebApp -DarchetypeArtifactId=maven-archetype-webapp -DinteractiveMode=false

具体示例：

C:\worksp>mvn archetype:generate -DgroupId=com.yiibai  -DartifactId=CounterWebAp
p -DarchetypeArtifactId=maven-archetype-webapp -DinteractiveMode=false
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building Maven Stub Project (No POM) 1
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] >>> maven-archetype-plugin:2.4:generate (default-cli) > generate-sources
@ standalone-pom >>>
[INFO]
[INFO] <<< maven-archetype-plugin:2.4:generate (default-cli) < generate-sources
@ standalone-pom <<<
[INFO]
[INFO] --- maven-archetype-plugin:2.4:generate (default-cli) @ standalone-pom --
-
[INFO] Generating project in Batch mode
Downloading: https://repo.maven.apache.org/maven2/org/apache/maven/archetypes/ma
ven-archetype-webapp/1.0/maven-archetype-webapp-1.0.jar
Downloaded: https://repo.maven.apache.org/maven2/org/apache/maven/archetypes/mav
en-archetype-webapp/1.0/maven-archetype-webapp-1.0.jar (4 KB at 0.1 KB/sec)
Downloading: https://repo.maven.apache.org/maven2/org/apache/maven/archetypes/ma
ven-archetype-webapp/1.0/maven-archetype-webapp-1.0.pom
Downloaded: https://repo.maven.apache.org/maven2/org/apache/maven/archetypes/mav
en-archetype-webapp/1.0/maven-archetype-webapp-1.0.pom (533 B at 0.1 KB/sec)
[INFO] -------------------------------------------------------------------------
---
[INFO] Using following parameters for creating project from Old (1.x) Archetype:
 maven-archetype-webapp:1.0
[INFO] -------------------------------------------------------------------------
---
[INFO] Parameter: basedir, Value: C:\worksp
[INFO] Parameter: package, Value: com.yiibai
[INFO] Parameter: groupId, Value: com.yiibai
[INFO] Parameter: artifactId, Value: CounterWebApp
[INFO] Parameter: packageName, Value: com.yiibai
[INFO] Parameter: version, Value: 1.0-SNAPSHOT
[INFO] project created from Old (1.x) Archetype in dir: C:\worksp\CounterWebApp
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 10:30 min
[INFO] Finished at: 2015-10-28T20:31:03+08:00
[INFO] Final Memory: 16M/174M
[INFO] ------------------------------------------------------------------------

新的Web项目命名为 “CounterWebApp”，以及一些标准的 web 目录结构也会自动创建。

2. 项目目录布局

查看生成的项目结构布局：

.|____CounterWebApp
||____pom.xml
||____src
|||____main
||||____resources
||||____webapp
|||||____index.jsp
|||||____WEB-INF
||||||____web.xml

Maven 产生了一些文件夹，一个部署描述符 web.xml，pom.xml 和 index.jsp。

注意，
请查看官方Maven标准目录布局指南来了解更多。

pom.xml

<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.yiibai</groupId>
  <artifactId>CounterWebApp</artifactId>
  <packaging>war</packaging>
  <version>1.0-SNAPSHOT</version>
  <name>CounterWebApp Maven Webapp</name>
  <url>http://maven.apache.org</url>
  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
  </dependencies>
  <build>
    <finalName>CounterWebApp</finalName>
  </build>
</project>

web.xml – Servlet 2.3 已经比较旧, 建议升级到2.5

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" ><web-app><display-name>Archetype Created Web Application</display-name></web-app>

index.jsp – 一个简单的 hello world html 页面文件

<html>
<body>
<div><div class="ads-in-post hide_if_width_less_800">
<script async src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>
<!-- 728x90 - After2ndH4 -->
<ins class="adsbygoogle hide_if_width_less_800" 
     style="display:inline-blockwidth:728pxheight:90px"
     data-ad-client="ca-pub-2836379775501347"
     data-ad-slot="3642936086"
	 data-ad-region="mkyongregion"></ins>
<script>
(adsbygoogle = window.adsbygoogle || []).push({})
</script>
</div></div><h2>Hello World!</h2>
</body>
</html>

3. Eclipse IDE 支持

要导入这个项目到Eclipse中，需要生成一些 Eclipse 项目的配置文件：

3.1、在终端，进入到 “CounterWebApp” 文件夹中，键入以下命令：

C:\worksp>cd CounterWebApp
C:\worksp\CounterWebApp>mvnꃬlipse:eclipse%uA0-Dwtpversion=2.0
[INFO]%uA0Scanning%uA0for%uA0projects...
Downloading:%uA0https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven -war-plugin/2.2/maven-war-plugin-2.2.pom
Downloaded:%uA0https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven- war-plugin/2.2/maven-war-plugin-2.2.pom%uA0(7%uA0KB%uA0at%uA02.5%uA0KB/sec)
Downloading:%uA0https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven -war-plugin/2.2/maven-war-plugin-2.2.jar
Downloaded:%uA0https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven- war-plugin/2.2/maven-war-plugin-2.2.jar%uA0(77%uA0KB%uA0atꀦ.2%uA0KB/sec)
[INFO]
[INFO]%uA0------------------------------------------------------------------------
[INFO]%uA0Building%uA0CounterWebApp%uA0Maven%uA0Webapp%uA01.0-SNAPSHOT
[INFO]%uA0------------------------------------------------------------------------
[INFO]
[INFO]%uA0>>>%uA0maven-eclipse-plugin:2.10:eclipse%uA0(default-cli)%uA0>%uA0generate-resources
@%uA0CounterWebApp%uA0>>>
[INFO]
[INFO]%uA0<<<%uA0maven-eclipse-plugin:2.10:eclipse%uA0(default-cli)%uA0<%uA0generate-resources
@%uA0CounterWebApp%uA0<<<
[INFO]
[INFO]%uA0---%uA0maven-eclipse-plugin:2.10:eclipse%uA0(default-cli)%uA0@%uA0CounterWebApp%uA0---
[INFO]ꂭding%uA0support%uA0for%uA0WTP%uA0version%uA02.0.
[INFO]%uA0Usingꃬlipse%uA0Workspace:%uA0null
[INFO]ꂭdingꃞfault%uA0classpath%uA0container:%uA0org.eclipse.jdt.launching.JRE_CONTAINER
[INFO]%uA0Not%uA0writing%uA0settings%uA0-ꃞfaults%uA0suffice
[INFO]%uA0Wroteꃬlipse%uA0project%uA0for%uA0"CounterWebApp"%uA0to%uA0C:\worksp\CounterWebApp.
[INFO]
[INFO]%uA0------------------------------------------------------------------------
[INFO]%uA0BUILD%uA0SUCCESS
[INFO]%uA0------------------------------------------------------------------------
[INFO]%uA0Total%uA0time:%uA07.982%uA0s
[INFO]%uA0Finished%uA0at:ꀠ15-10-28T20:24:57+08:00
[INFO]%uA0Final%uA0Memory:ꀕM/146M
[INFO]%uA0------------------------------------------------------------------------

注意，此选项 -Dwtpversion=2.0 告诉 Maven 将项目转换到 Eclipse 的 Web 项目(WAR)，而不是默认的Java项目(JAR)。为方便起见，以后我们会告诉你如何配置 pom.xml 中的这个 WTP 选项。

3.2 导入到 Eclipse IDE – File -> Import… -> General -> Existing Projects into workspace.

图像说明: 在 Eclipse 中，如果看到项目顶部有地球图标，意味着这是一个 Web 项目。

4. 更新POM

在Maven中，Web项目的设置都通过这个单一的pom.xml文件配置。

添加项目依赖 - Spring, logback 和 JUnit
添加插件来配置项目

阅读注释清楚明了。

	pom.xml

<project%uA0xmlns="http://maven.apache.org/POM/4.0.0"%uA0
%uA0%uA0%uA0%uA0xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0%uA0 http://maven.apache.org/maven-v4_0_0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>com.yiibai</groupId>
	<artifactId>CounterWebApp</artifactId>
	<packaging>war</packaging>
	<version>1.0-SNAPSHOT</version>
	<name>CounterWebApp%uA0Maven%uA0Webapp</name>
	<url>http://maven.apache.org</url> <properties>
		<jdk.version>1.7</jdk.version>
		<spring.version>4.1.1.RELEASE</spring.version>
		<jstl.version>1.2</jstl.version>
		<junit.version>4.11</junit.version>
		<logback.version>1.0.13</logback.version>
		<jcl-over-slf4j.version>1.7.5</jcl-over-slf4j.version>
	</properties>

	<dependencies>
		<!--%uA0Unit%uA0Test%uA0-->
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>${junit.version}</version>
		</dependency>

		<!--%uA0Spring%uA0Core%uA0-->
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-core</artifactId>
			<version>${spring.version}</version>
			<exclusions>
				<exclusion>
					<groupId>commons-logging</groupId>
					<artifactId>commons-logging</artifactId>
				</exclusion>
			</exclusions>
		</dependency>

		<dependency>
			<groupId>org.slf4j</groupId>
			<artifactId>jcl-over-slf4j</artifactId>
			<version>${jcl-over-slf4j.version}</version>
		</dependency>
		<dependency>
			<groupId>ch.qos.logback</groupId>
			<artifactId>logback-classic</artifactId>
			<version>${logback.version}</version>
		</dependency>

		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-web</artifactId>
			<version>${spring.version}</version>
		</dependency>

		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-webmvc</artifactId>
			<version>${spring.version}</version>
		</dependency>
		<!--%uA0jstl%uA0-->
		<dependency>
			<groupId>jstl</groupId>
			<artifactId>jstl</artifactId>
			<version>${jstl.version}</version>
		</dependency>
	</dependencies>

	<build>
		<finalName>CounterWebApp</finalName>

		<plugins>
		%uA0%uA0%uA0%uA0<!--ꃬlipse%uA0project%uA0-->
		%uA0%uA0<plugin>
			<groupId>org.apache.maven.plugins</groupId>
			<artifactId>maven-eclipse-plugin</artifactId>
			<version>2.9</version>
			<configuration>
			%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0<!--%uA0Always%uA0download%uA0and%uA0attachꃞpendencies%uA0source%uA0code%uA0-->
				<downloadSources>true</downloadSources>
				<downloadJavadocs>false</downloadJavadocs>
				<!--%uA0Avoid%uA0type%uA0mvnꃬlipse:eclipse%uA0-Dwtpversion=2.0%uA0-->
				<wtpversion>2.0</wtpversion>
			</configuration>
		%uA0%uA0</plugin>

		%uA0%uA0<!--%uA0Set%uA0JDK%uA0Compiler%uA0Level%uA0-->
		%uA0%uA0<plugin>
			<groupId>org.apache.maven.plugins</groupId>
			<artifactId>maven-compiler-plugin</artifactId>
			<version>2.3.2</version>
			<configuration>
				<source>${jdk.version}</source>
				<target>${jdk.version}</target>
			</configuration>
		%uA0%uA0</plugin>

		%uA0%uA0<!--%uA0For%uA0Maven%uA0Tomcat%uA0Plugin%uA0-->
		%uA0%uA0<plugin>
			<groupId>org.apache.tomcat.maven</groupId>
			<artifactId>tomcat7-maven-plugin</artifactId>
			<version>2.2</version>
			<configuration>
				<path>/CounterWebApp</path>
			</configuration>
		%uA0%uA0</plugin>
		</plugins>
	</build>
</project>

注意，为方便起见，声明 maven-eclipse-plugin，并配置wtpversion 来避免输入参数 -Dwtpversion=2.0。现在，每次使用 mvn eclipse:eclipse，Maven将这个项目导入转换为 Eclipse Web 项目。

#之前 
mvn eclipse:eclipse --> Eclipse Java project (JAR)
mvn eclipse:eclipse -Dwtpversion=2.0 --> Eclipse Java web project (WAR)

#之后
mvn eclipse:eclipse --> Eclipse Java web project (WAR)

5. 更新源代码

在这一步中，在上一步配置完pom.xml后，重新执行 mvn eclipse:eclipse 这个命令，我们将创建Spring MVC的一些文件和logback日志框架的文件夹，最终的项目结构如下所示：

.
|____pom.xml
|____src
| |____main
| | |____java
| | | |____com
| | | | |____yiibai
| | | | | |____controller
| | | | | | |____BaseController.java
| | |____resources
| | | |____logback.xml
| | |____webapp
| | | |____WEB-INF
| | | | |____mvc-dispatcher-servlet.xml
| | | | |____pages
| | | | | |____index.jsp
| | | | |____web.xml

注意，如果它不存在，需要手动创建文件夹。

5.1 创建 Spring MVC 的控制器类。

/src/main/java/com/yiibai/controller/BaseController.java

package com.yiibai.controller

import org.slf4j.LoggerFactory
import org.springframework.stereotype.Controller
import org.springframework.ui.ModelMap
import org.springframework.web.bind.annotation.PathVariable
import org.springframework.web.bind.annotation.RequestMapping
import org.springframework.web.bind.annotation.RequestMethod

@Controller
public class BaseController {

	private static int counter = 0
	private static final String VIEW_INDEX = "index"
	private final static org.slf4j.Logger logger = LoggerFactory.getLogger(BaseController.class)

	@RequestMapping(value = "/", method = RequestMethod.GET)
	public String welcome(ModelMap model) {

		model.addAttribute("message", "Welcome")
		model.addAttribute("counter", ++counter)
		logger.debug("[welcome] counter : {}", counter)

		// Spring uses InternalResourceViewResolver and return back index.jsp
		return VIEW_INDEX

	}

	@RequestMapping(value = "/{name}", method = RequestMethod.GET)
	public String welcomeName(@PathVariable String name, ModelMap model) {

		model.addAttribute("message", "Welcome " + name)
		model.addAttribute("counter", ++counter)
		logger.debug("[welcomeName] counter : {}", counter)
		return VIEW_INDEX

	}

}

5.2 创建Spring配置文件。

	/src/main/webapp/WEB-INF/mvc-dispatcher-servlet.xml

<beans%uA0xmlns="http://www.springframework.org/schema/beans"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="
%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0http://www.springframework.org/schema/beans%uA0%uA0%uA0%uA0%uA0
%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0http://www.springframework.org/schema/beans/spring-beans.xsd %uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0http://www.springframework.org/schema/context%uA0
%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0http://www.springframework.org/schema/context/spring-context.xsd">

	<context:component-scanꂺse-package="com.yiibai.controller"%uA0/>
	<bean
		class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<property%uA0name="prefix">
			<value>/WEB-INF/pages/</value>
		</property>
		<property%uA0name="suffix">
			<value>.jsp</value>
		</property>
	</bean>

</beans>

5.3 更新让现有的 web.xml 支持 Servlet 2.5(默认的Servlet2.3 太旧了)，%uA0并且还通过 Spring 监听器 ContextLoaderListener 集成了Spring框架。

	/src/main/webapp/WEB-INF/web.xml

<web-app%uA0xmlns="http://java.sun.com/xml/ns/javaee"%uA0
%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee%uA0
	%uA0%uA0%uA0%uA0%uA0%uA0http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
	version="2.5">

	<display-name>Counter%uA0Web%uA0Application</display-name>

	<servlet>
		<servlet-name>mvc-dispatcher</servlet-name>
		<servlet-class>
%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0org.springframework.web.servlet.DispatcherServlet
%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0</servlet-class>
		<load-on-startup>1</load-on-startup>
	</servlet>

	<servlet-mapping>
		<servlet-name>mvc-dispatcher</servlet-name>
		<url-pattern>/</url-pattern>
	</servlet-mapping>

	<context-param>
		<param-name>contextConfigLocation</param-name>
		<param-value>/WEB-INF/mvc-dispatcher-servlet.xml</param-value>
	</context-param>

	<listener>
		<listener-class>
%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0org.springframework.web.context.ContextLoaderListener
%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0%uA0</listener-class>
	</listener>
</web-app>

5.4 移动文件%uA0index.jsp%uA0到%uA0WEB-INF/pages%uA0目录下，为了保护直接访问。并更新内容：

/src/main/webapp/WEB-INF/pages/index.jsp

5.5 在资源文件夹(resources)中创建 logback.xml 文件

	/src/main/resources/logback.xml

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

6. Eclipse + Tomcat

在第5步中创建所有文件以后，这里有一些方法可以用来部署和测试Web项目，我们这里推荐使用6.2中的方法。

6.1 要编译，测试和项目打包成一个WAR文件，输入：

mvn package

一个新的 WAR 文件将在 project/target/CounterWebApp.war产生，只需复制并部署到Tomcat 发布的目录。

6.2 如果想通过 Eclipse 服务器这个项目插件(Tomcat 或其它容器)调试，这里再输入：

mvn eclipse:eclipse

如果一切顺利，该项目的依赖将被装配附加到 Web部署项目。图片: 右键点击 project -> Properties -> Deployment Assembly

6.3 Maven 的 Tomcat 插件声明(加入到 pom.xml)：

	pom.xml

<!-- For Maven Tomcat Plugin -->

键入以下命令(有时网络不通畅需要执行2-3次)：

mvn tomcat:run
tp://logback.qos.ch/codes.html#layoutInsteadOfEncoder%uA0forꃞtails
20:37:32,089%uA0|-INFO%uA0in%uA0ch.qos.logback.classic.joran.action.LoggerAction%uA0-%uA0Se
g%uA0level%uA0of%uA0logger%uA0[com.yiibai.controller]%uA0toꃞBUG
20:37:32,089%uA0|-INFO%uA0in%uA0ch.qos.logback.classic.joran.action.LoggerAction%uA0-%uA0Se
gꂭditivity%uA0of%uA0logger%uA0[com.yiibai.controller]%uA0toꃺlse
20:37:32,090%uA0|-INFO%uA0in%uA0ch.qos.logback.core.joran.action.AppenderRefAction%uA0-
ching%uA0appender%uA0named%uA0[STDOUT]%uA0to%uA0Logger[com.yiibai.controller]
20:37:32,090%uA0|-INFO%uA0in%uA0ch.qos.logback.classic.joran.action.RootLoggerAction
tting%uA0level%uA0of%uA0ROOT%uA0logger%uA0to%uA0ERROR
20:37:32,090%uA0|-INFO%uA0in%uA0ch.qos.logback.core.joran.action.AppenderRefAction%uA0-
ching%uA0appender%uA0named%uA0[STDOUT]%uA0to%uA0Logger[ROOT]
20:37:32,090%uA0|-INFO%uA0in%uA0ch.qos.logback.classic.joran.action.ConfigurationActi
%uA0End%uA0of%uA0configuration.
20:37:32,091%uA0|-INFO%uA0in%uA0ch.qos.logback.classic.joran.JoranConfigurator@3bead5 %uA0Registering%uA0current%uA0configuration%uA0as%uA0safeꃺllback%uA0point

十月ꀨ,ꀠ15ꀠ:37:32%uA0下午%uA0org.apache.catalina.core.ApplicationContext%uA0log
信息:%uA0Initializing%uA0Spring%uA0root%uA0WebApplicationContext
十月ꀨ,ꀠ15ꀠ:37:33%uA0下午%uA0org.apache.catalina.core.ApplicationContext%uA0log
信息:%uA0Initializing%uA0Spring%uA0FrameworkServlet%uA0&aposmvc-dispatcher&apos
十月ꀨ,ꀠ15ꀠ:37:33%uA0下午%uA0org.apache.coyote.http11.Http11Protocol%uA0init
信息:%uA0Initializing%uA0Coyote%uA0HTTP/1.1%uA0on%uA0http-8080
十月ꀨ,ꀠ15ꀠ:37:33%uA0下午%uA0org.apache.coyote.http11.Http11Protocol%uA0start
信息:%uA0Starting%uA0Coyote%uA0HTTP/1.1%uA0on%uA0http-8080

这将启动Tomcat，部署项目默认在端口8080。

出错：Maven项目下update%uA0maven后Eclipse报错：java.lang.ClassNotFoundException:%uA0ContextLoaderL

解决方案：

1.右键点击项目--选择Properties

选择Deployment Assembly,在右边点击Add按钮，在弹出的窗口中选择Java Build Path Entries

2.点击Next，选择Maven Dependencies

3.点击Finish，然后可以看到已经把Maven Dependencies添加到Web应用结构中了

操作完后，重新部署工程，不再报错了。然后我们再到.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\目录下，发现工程WEB-INF目录下自动生成了lib目录，并且所有的依赖jar包也都已经部署进来。问题因此解决。

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