http://www.mkyong.com/maven/how-to-create-a-web-application-project-with-maven/

不念不忘少年蓝@ 2022-08-13 12:39 161阅读 0赞

In this tutorial, we will show you how to use Maven to create a Java web application (with Spring MVC) project, and make it support Eclipse IDE.

Tools used :

1.  Maven 3.0.5
2.  Eclipse 4.2
3.  JDK 6
4.  Spring 3.2.0.RELEASED
5.  Tomcat 7

#### 1. Web Application Project from Maven Template ####

In a terminal (\*uix or Mac) or command prompt (Windows), navigate to the folder you want to store the project. Issue following command :

mvn archetype:generate -DgroupId={ project-packaging} -DartifactId={ project-name} -DarchetypeArtifactId=maven-archetype-webapp -DinteractiveMode=false

This tell Maven to create a Java web application project from “**maven-archetype-webapp**” template.

For example,

$ pwd
    /Users/mkyong/Documents/workspace
     
    $ mvn archetype:generate -DgroupId=com.mkyong -DartifactId=CounterWebApp -DarchetypeArtifactId=maven-archetype-webapp -DinteractiveMode=false
    [INFO] Scanning for projects...
    [INFO]                                                                         
    [INFO] ------------------------------------------------------------------------
    [INFO] Building Maven Stub Project (No POM) 1
    [INFO] ------------------------------------------------------------------------
    [INFO] 
    [INFO] Generating project in Batch mode
    [INFO] ----------------------------------------------------------------------------
    [INFO] Using following parameters for creating project from Old (1.x) Archetype: maven-archetype-webapp:1.0
    [INFO] ----------------------------------------------------------------------------
    [INFO] Parameter: groupId, Value: com.mkyong
    [INFO] Parameter: packageName, Value: com.mkyong
    [INFO] Parameter: package, Value: com.mkyong
    [INFO] Parameter: artifactId, Value: CounterWebApp
    [INFO] Parameter: basedir, Value: /Users/mkyong/Documents/workspace
    [INFO] Parameter: version, Value: 1.0-SNAPSHOT
    [INFO] project created from Old (1.x) Archetype in dir: /Users/mkyong/Documents/workspace/CounterWebApp
    [INFO] ------------------------------------------------------------------------
    [INFO] BUILD SUCCESS
    [INFO] ------------------------------------------------------------------------
    [INFO] Total time: 3.147s
    [INFO] Finished at: Thu Dec 20 20:35:19 MYT 2012
    [INFO] Final Memory: 12M/128M
    [INFO] ------------------------------------------------------------------------

In above case, a new web application project named “**CounterWebApp**“, and the entire project directory structure is created automatically.

#### 2. Maven Directory Layout ####

Maven created following web application directory layout. A standard deployment descriptor`web.xml` and Maven `pom.xml` are created.

**Note**  
Please check this [ official guide][official guide] to understand more.

pom.xml

web.xml – Servlet 2.3 is too old, consider upgrade to 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 – A simple hello world html file

<html>
    <body>
    <h2>Hello World!</h2>
    </body>
    </html>

#### 3. Eclipse IDE Support ####

To convert the Maven web project to support Eclipse IDE, in terminal, navigate to “CounterWebAPp” folder, issue this command :

mvn eclipse:eclipse -Dwtpversion=2.0

You must add the `-Dwtpversion=2.0` argument to make it as a Eclipse web project. Imports it into Eclipse IDE, a globe icon on top of project, means this is a web project in Eclipse.

![project structure][]

**You want Eclipse web project NOT Eclipse Java project.**  
Many users are confused, again, if you just issue `mvn eclipse:eclipse`, it will only convert the project as Eclipse Java project, add extra `-Dwtpversion=2.0` argument to make it as Eclipse web project.

Done. This web project is ready to deploy. Attached to Eclipse’s Tomcat server plugin, and start it.

![tomcat in eclipse][]

You can access the hello world jsp via – *http://localhost:8080/CounterWebApp/*

#### 4. Update POM ####

To make above Maven web project to support Spring MVC framework, we need to touch up on the existing`pom.xml` :

1.  Add compiler plugin to specify JDK6 to compile this project (default is using JDK1.4).
2.  Add Spring frameworks dependencies.
3.  Update jUnit to latest 4.11.

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.mkyong</groupId>
    	<artifactId>CounterWebApp</artifactId>
    	<packaging>war</packaging>
    	<version>1.0-SNAPSHOT</version>
    	<name>CounterWebApp Maven Webapp</name>
    	<url>http://maven.apache.org</url>
     
    	<properties>
    		<spring.version>3.0.5.RELEASE</spring.version>
    		<junit.version>4.11</junit.version>
    		<jdk.version>1.6</jdk.version>
    	</properties>
     
    	<dependencies>
     
    		
    		<dependency>
    			<groupId>org.springframework</groupId>
    			<artifactId>spring-core</artifactId>
    			<version>${spring.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>
     
    		<dependency>
    			<groupId>junit</groupId>
    			<artifactId>junit</artifactId>
    			<version>${junit.version}</version>
    			<scope>test</scope>
    		</dependency>
    	</dependencies>
    	<build>
    		<finalName>CounterWebApp</finalName>
    		<plugins>
    			<plugin>
    				<groupId>org.apache.maven.plugins</groupId>
    				<artifactId>maven-compiler-plugin</artifactId>
    				<version>3.0</version>
    				<configuration>
    					<source>${jdk.version}</source>
    					<target>${jdk.version}</target>
    				</configuration>
    			</plugin>
    		</plugins>
    	</build>
    </project>

#### 5. Spring MVC REST ####

Create a Spring MVC controller class, with two simple methods to print a message.

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

package com.mkyong.controller;
     
    import org.springframework.stereotype.Controller;
    import org.springframework.ui.ModelMap;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestMethod;
     
    @Controller
    @RequestMapping("/")
    public class BaseController { 
     
    	@RequestMapping(value="/welcome", method = RequestMethod.GET)
    	public String welcome(ModelMap model) { 
     
    		model.addAttribute("message", "Maven Web Project + Spring 3 MVC - welcome()");
     
    		//Spring uses InternalResourceViewResolver and return back index.jsp
    		return "index";
     
    	}
     
    	@RequestMapping(value="/welcome/{name}", method = RequestMethod.GET)
    	public String welcomeName(@PathVariable String name, ModelMap model) { 
     
    		model.addAttribute("message", "Maven Web Project + Spring 3 MVC - " + name);
    		return "index";
     
    	}
     
    }

Create a Spring configuration file, defines the Spring view resolver.

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

<beans xmlns="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="
     http://www.springframework.org/schema/beans 
     http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
     http://www.springframework.org/schema/context 
     http://www.springframework.org/schema/context/spring-context-3.0.xsd">
     
    	<context:component-scan base-package="com.mkyong.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>

Update existing `web.xml` to support Servlet 2.5 (the default Servlet 2.3 is too old), and also integrates Spring framework into this web application project via Spring’s listener`ContextLoaderListener`.

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

<web-app xmlns="http://java.sun.com/xml/ns/javaee"
    	      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    	      xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
     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>

Move existing `index.jsp` inside folder `WEB-INF`, to protect user access it directly. In additional, edit the file to print out the`${message}` variable that pass by the controller.

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

<html>
    <body>
    <h2>Hello World!</h2>
     
    <h4>Message : ${message}</h1>	
    </body>
    </html>

Review the final directory structure

![final project structure][]

#### 6. Eclipse + Tomcat ####

In order to start or debug this project via Eclipse server plugin (Tomcat or other container). You need to issue following command again, in order to make all dependencies attached to the project web deployment assembly.

mvn eclipse:eclipse -Dwtpversion=2.0

Before this command, project dependencies are empty.

![web deployment assembly][]

After this command, now project dependdencies are here!

![web deployment assembly][web deployment assembly 1]

**Important!**  
Many developers are trapped here, and failed to perform the starting or debugging in Eclipse server plugin, all failed by showing dependencies not found error message. Right click on your project properties, make sure all dependencies are inside the web deployment assembly, otherwise issue `mvn eclipse:eclipse -Dwtpversion=2.0` again!

#### 7. Maven Packaging ####

Review the `pom.xml` again, the `packaging` tag defining what is the packaging format or output.

pom.xml

<project ...>
    	<modelVersion>4.0.0</modelVersion>
    	<groupId>com.mkyong</groupId>
    	<artifactId>CounterWebApp</artifactId>
     
    	<packaging>war</packaging>
    	<version>1.0-SNAPSHOT</version>

Package the project to deploy is easy, just issue `mvn package`, it compiles and package the web project into a “war” file and store in`project/target` folder.

For example :

$pwd
    /Users/mkyong/Documents/workspace/CounterWebApp
     
    Yongs-MacBook-Air:CounterWebApp mkyong$ mvn package
    [INFO] Scanning for projects...
    [INFO]                                                                         
    [INFO] ------------------------------------------------------------------------
    [INFO] Building CounterWebApp Maven Webapp 1.0-SNAPSHOT
    [INFO] ------------------------------------------------------------------------
    [INFO] -- omitted for readability
    [INFO] 
    [INFO] --- maven-war-plugin:2.1.1:war (default-war) @ CounterWebApp ---
    [INFO] Packaging webapp
    [INFO] Assembling webapp [CounterWebApp] in [/Users/mkyong/Documents/workspace/CounterWebApp/target/CounterWebApp]
    [INFO] Processing war project
    [INFO] Copying webapp resources [/Users/mkyong/Documents/workspace/CounterWebApp/src/main/webapp]
    [INFO] Webapp assembled in [87 msecs]
    [INFO] Building war: /Users/mkyong/Documents/workspace/CounterWebApp/target/CounterWebApp.war
    [INFO] WEB-INF/web.xml already added, skipping
    [INFO] ------------------------------------------------------------------------
    [INFO] BUILD SUCCESS
    [INFO] ------------------------------------------------------------------------
    [INFO] Total time: 3.936s
    [INFO] Finished at: Thu Dec 20 22:28:53 MYT 2012
    [INFO] Final Memory: 14M/206M
    [INFO] ------------------------------------------------------------------------

Done, just copy the `project/target/CounterWebApp.war` file and deploy to your container.

#### 8. Demo ####

Start the web application.

*http://localhost:8080/CounterWebApp/welcome*

![demo1][]

*http://localhost:8080/CounterWebApp/welcome/mkyong*

![demo2][]

#### Download Source Code ####

Download it – [ CounterWebApp.zip][CounterWebApp.zip] (13 KB)

#### References ####

1.  [Apache Maven Project][]
2.  [How To Create A Java Project With Maven][]
3.  [Spring 3 REST Hello World Example][]
4.  [A Simple Web Application][]

[official guide]: http://maven.apache.org/guides/introduction/introduction-to-the-standard-directory-layout.html
[project structure]: http://www.mkyong.com/wp-content/uploads/2011/04/project-structure.png
[tomcat in eclipse]: http://www.mkyong.com/wp-content/uploads/2011/04/eclipse-tomcat-server.png
[final project structure]: http://www.mkyong.com/wp-content/uploads/2011/04/final-folder.png
[web deployment assembly]: http://www.mkyong.com/wp-content/uploads/2011/04/web-deployment-assembly.png
[web deployment assembly 1]: http://www.mkyong.com/wp-content/uploads/2011/04/web-deployment-assembly-2.png
[demo1]: http://www.mkyong.com/wp-content/uploads/2011/04/demo1.png
[demo2]: http://www.mkyong.com/wp-content/uploads/2011/04/demo2.png
[CounterWebApp.zip]: http://www.mkyong.com/wp-content/uploads/2011/04/CounterWebApp.zip
[Apache Maven Project]: http://maven.apache.org/index.html
[How To Create A Java Project With Maven]: http://www.mkyong.com/maven/how-to-create-a-java-project-with-maven/
[Spring 3 REST Hello World Example]: http://www.mkyong.com/spring-mvc/spring-3-rest-hello-world-example/
[A Simple Web Application]: http://www.sonatype.com/books/mvnex-book/reference/web.html

http://www.mkyong.com/maven/how-to-create-a-web-application-project-with-maven/

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