使用Maven创建Web应用程序项目 - Maven教程

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：

  1. Maven 3.3.3
  2. Eclipse 4.3
  3. JDK 8
  4. Spring 4.1.1.RELEASED
  5. Tomcat 7
  6. 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-block;width:728px;height: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>mvn eclipse:eclipse -Dwtpversion=2.0
[INFO] Scanning for projects...
Downloading: [https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven](https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven) -war-plugin/2.2/maven-war-plugin-2.2.pom
Downloaded: [https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-](https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-) war-plugin/2.2/maven-war-plugin-2.2.pom (7 KB at 2.5 KB/sec)
Downloading: [https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven](https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven) -war-plugin/2.2/maven-war-plugin-2.2.jar
Downloaded: [https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-](https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-) war-plugin/2.2/maven-war-plugin-2.2.jar (77 KB at 26.2 KB/sec)
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building CounterWebApp Maven Webapp 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] >>> maven-eclipse-plugin:2.10:eclipse (default-cli) > generate-resources
@ CounterWebApp >>>
[INFO]
[INFO] <<< maven-eclipse-plugin:2.10:eclipse (default-cli) < generate-resources
@ CounterWebApp <<<
[INFO]
[INFO] --- maven-eclipse-plugin:2.10:eclipse (default-cli) @ CounterWebApp ---
[INFO] Adding support for WTP version 2.0.
[INFO] Using Eclipse Workspace: null
[INFO] Adding default classpath container: org.eclipse.jdt.launching.JRE_CONTAINER
[INFO] Not writing settings - defaults suffice
[INFO] Wrote Eclipse project for "CounterWebApp" to C:\worksp\CounterWebApp.
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 7.982 s
[INFO] Finished at: 2015-10-28T20:24:57+08:00
[INFO] Final Memory: 15M/146M
[INFO] ------------------------------------------------------------------------

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.

project structure

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。

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

阅读注释清楚明了。

pom.xml

<project xmlns="[http://maven.apache.org/POM/4.0.0](http://maven.apache.org/POM/4.0.0)" 
    xmlns:xsi="[http://www.w3.org/2001/XMLSchema-instance](http://www.w3.org/2001/XMLSchema-instance)"
    xsi:schemaLocation="[http://maven.apache.org/POM/4.0.0](http://maven.apache.org/POM/4.0.0)  [http://maven.apache.org/maven-v4_0_0.xsd](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>](http://maven.apache.org%3C/url%3E) <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>
        <!-- Unit Test -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>${junit.version}</version>
        </dependency>

        <!-- Spring Core -->
        <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>${spring.version}</version>
        </dependency>
        <!-- jstl -->
        <dependency>
            <groupId>jstl</groupId>
            <artifactId>jstl</artifactId>
            <version>${jstl.version}</version>
        </dependency>
    </dependencies>

    <build>
        <finalName>CounterWebApp</finalName>

        <plugins>
            <!-- Eclipse project -->
          <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-eclipse-plugin</artifactId>
            <version>2.9</version>
            <configuration>
                    <!-- Always download and attach dependencies source code -->
                <downloadSources>true</downloadSources>
                <downloadJavadocs>false</downloadJavadocs>
                <!-- Avoid type mvn eclipse:eclipse -Dwtpversion=2.0 -->
                <wtpversion>2.0</wtpversion>
            </configuration>
          </plugin>

          <!-- Set JDK Compiler Level -->
          <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>
          </plugin>

          <!-- For Maven Tomcat Plugin -->
          <plugin>
            <groupId>org.apache.tomcat.maven</groupId>
            <artifactId>tomcat7-maven-plugin</artifactId>
            <version>2.2</version>
            <configuration>
                <path>/CounterWebApp</path>
            </configuration>
          </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 xmlns="[http://www.springframework.org/schema/beans](http://www.springframework.org/schema/beans)"
    xmlns:context="[http://www.springframework.org/schema/context](http://www.springframework.org/schema/context)"
    xmlns:xsi="[http://www.w3.org/2001/XMLSchema-instance](http://www.w3.org/2001/XMLSchema-instance)"
    xsi:schemaLocation="
        [http://www.springframework.org/schema/beans](http://www.springframework.org/schema/beans)     
        [http://www.springframework.org/schema/beans/spring-beans.xsd](http://www.springframework.org/schema/beans/spring-beans.xsd)         [http://www.springframework.org/schema/context](http://www.springframework.org/schema/context) 
        [http://www.springframework.org/schema/context/spring-context.xsd](http://www.springframework.org/schema/context/spring-context.xsd)">

    <context:component-scan base-package="com.yiibai.controller" />
    <bean
        class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix">
            <value>/WEB-INF/pages/</value>
        </property>
        <property name="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)， 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 xmlns="[http://java.sun.com/xml/ns/javaee](http://java.sun.com/xml/ns/javaee)" 
        xmlns:xsi="[http://www.w3.org/2001/XMLSchema-instance](http://www.w3.org/2001/XMLSchema-instance)"
    xsi:schemaLocation="[http://java.sun.com/xml/ns/javaee](http://java.sun.com/xml/ns/javaee) 
          [http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd](http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd)"
    version="2.5">

    <display-name>Counter Web Application</display-name>

    <servlet>
        <servlet-name>mvc-dispatcher</servlet-name>
        <servlet-class>
                        org.springframework.web.servlet.DispatcherServlet
                </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>
                   org.springframework.web.context.ContextLoaderListener
                </listener-class>
    </listener>
</web-app>

5.4 移动文件 index.jsp 到 WEB-INF/pages 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 for details
20:37:32,089 |-INFO in ch.qos.logback.classic.joran.action.LoggerAction - Se
g level of logger [com.yiibai.controller] to DEBUG
20:37:32,089 |-INFO in ch.qos.logback.classic.joran.action.LoggerAction - Se
g additivity of logger [com.yiibai.controller] to false
20:37:32,090 |-INFO in ch.qos.logback.core.joran.action.AppenderRefAction -
ching appender named [STDOUT] to Logger[com.yiibai.controller]
20:37:32,090 |-INFO in ch.qos.logback.classic.joran.action.RootLoggerAction
tting level of ROOT logger to ERROR
20:37:32,090 |-INFO in ch.qos.logback.core.joran.action.AppenderRefAction -
ching appender named [STDOUT] to Logger[ROOT]
20:37:32,090 |-INFO in ch.qos.logback.classic.joran.action.ConfigurationActi
 End of configuration.
20:37:32,091 |-INFO in [ch.qos.logback.classic.joran.JoranConfigurator@3bead5](mailto:ch.qos.logback.classic.joran.JoranConfigurator@3bead5)  Registering current configuration as safe fallback point

十月 28, 2015 20:37:32 下午 org.apache.catalina.core.ApplicationContext log
信息: Initializing Spring root WebApplicationContext
十月 28, 2015 20:37:33 下午 org.apache.catalina.core.ApplicationContext log
信息: Initializing Spring FrameworkServlet 'mvc-dispatcher'
十月 28, 2015 20:37:33 下午 org.apache.coyote.http11.Http11Protocol init
信息: Initializing Coyote HTTP/1.1 on http-8080
十月 28, 2015 20:37:33 下午 org.apache.coyote.http11.Http11Protocol start
信息: Starting Coyote HTTP/1.1 on http-8080

这将启动Tomcat，部署项目默认在端口8080。

出错：Maven项目下update maven后Eclipse报错：java.lang.ClassNotFoundException: ContextLoaderL

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。