详细描述用maven构建Struts2项目
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构建后目录结果如下：
struts2 和struts1有很大的不同，它的核心特征是所有的实现都是通过interceptors(拦截器)，“value stack” (值栈)，OGNL(表达式语言)，以及包含了很多的注解使框架使用起来更简单。
下面一步一步构建学习Struts2。
工具：
1： Maven Apache Maven 3.0.4
2: JDK 1.7.0_10
3: Eclipse4.2
4: apache-tomcat-6.0.35
首先通过Maven构建一个Web项目。
Maven构建web项目的命令如下：
mvn archetype:generate -DgroupId={project-packaging} -DartifactId={project-name} -DarchetypeArtifactId=maven-archetype-webapp -DinteractiveMode=false
然后构建我们的项目，首先进入到项目放置的位置：
然后执行构建命令：如下：
E:\struts2>mvn archetype:generate -DgroupId=com.topwqp -DartifactId=Struts2Examp le -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:2.2:generate (default-cli) @ standalone-pom >> > [INFO] [INFO] <<< maven-archetype-plugin:2.2:generate (default-cli) @ standalone-pom << < [INFO] [INFO] --- maven-archetype-plugin:2.2:generate (default-cli) @ standalone-pom -- - [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.topwqp [INFO] Parameter: packageName, Value: com.topwqp [INFO] Parameter: package, Value: com.topwqp [INFO] Parameter: artifactId, Value: Struts2Example [INFO] Parameter: basedir, Value: E:\struts2 [INFO] Parameter: version, Value: 1.0-SNAPSHOT [INFO] project created from Old (1.x) Archetype in dir: E:\struts2\Struts2Exampl e [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 23.207s [INFO] Finished at: Sat May 04 10:57:34 CST 2013 [INFO] Final Memory: 9M/24M [INFO] ------------------------------------------------------------------------ E:\struts2>构建成功后，生成的web项目的目录结构为：
|-src
|---main
|-----resources
|-----webapp
|-------index.jsp
|-------WEB-INF
|---------web.xml
|-pom.xml
然后把需要引入的jar包在pom.xml中进行配置。
配置后的pom.xml文件如下：
<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.topwqp</groupId>
<artifactId>Struts2Example</artifactId>
<packaging>war</packaging>
<version>1.0-SNAPSHOT</version>
<name>Struts2Example 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>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.apache.struts</groupId>
<artifactId>struts2-core</artifactId>
<version>2.3.1.2</version>
</dependency>
<dependency>
<groupId>javassist</groupId>
<artifactId>javassist</artifactId>
<version>3.12.1.GA</version>
</dependency>
</dependencies>
<build>
<finalName>Struts2Example</finalName>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.2</version>
<configuration>
<source>1.7</source>
<target>1.7</target>
</configuration>
</plugin>
</plugins>
</build>
</project>
配置pom.xml后，下一步需要导入到eclipse中，如果导入到eclispe中需要对项目进行转换，
转换为eclipse项目的命令 mvn eclipse:eclipse -Dwtpversion=2.0
如果运行以上命令首先需要进入到pom.xml的文件目录下：
运行结果如下：
E:\struts2>cd Struts2Example E:\struts2\Struts2Example>mvn eclipse:eclipse -Dwtpversion=2.0 [INFO] Scanning for projects... [INFO] [INFO] ------------------------------------------------------------------------ [INFO] Building Struts2Example Maven Webapp 1.0-SNAPSHOT [INFO] ------------------------------------------------------------------------ [INFO] [INFO] >>> maven-eclipse-plugin:2.9:eclipse (default-cli) @ Struts2Example >>> [INFO] [INFO] <<< maven-eclipse-plugin:2.9:eclipse (default-cli) @ Struts2Example <<< [INFO] [INFO] --- maven-eclipse-plugin:2.9:eclipse (default-cli) @ Struts2Example --- [INFO] Adding support for WTP version 2.0. [INFO] Using Eclipse Workspace: null [INFO] Adding default classpath container: org.eclipse.jdt.launching.JRE_CONTAIN ER Downloading: http://uk.maven.org/maven2/org/apache/struts/struts2-core/2.3.1.2/s truts2-core-2.3.1.2.pom Downloaded: http://uk.maven.org/maven2/org/apache/struts/struts2-core/2.3.1.2/st ruts2-core-2.3.1.2.pom (12 KB at 4.2 KB/sec) Downloading: http://uk.maven.org/maven2/org/apache/struts/struts2-parent/2.3.1.2 /struts2-parent-2.3.1.2.pom Downloaded: http://uk.maven.org/maven2/org/apache/struts/struts2-parent/2.3.1.2/ struts2-parent-2.3.1.2.pom (27 KB at 33.2 KB/sec) Downloading: http://uk.maven.org/maven2/org/apache/struts/struts-master/8/struts -master-8.pom Downloaded: http://uk.maven.org/maven2/org/apache/struts/struts-master/8/struts- master-8.pom (9 KB at 20.9 KB/sec) Downloading: http://uk.maven.org/maven2/org/apache/apache/8/apache-8.pom Downloaded: http://uk.maven.org/maven2/org/apache/apache/8/apache-8.pom (14 KB a t 32.6 KB/sec) Downloading: http://uk.maven.org/maven2/org/apache/struts/xwork/xwork-core/2.3.1 .2/xwork-core-2.3.1.2.pom Downloaded: http://uk.maven.org/maven2/org/apache/struts/xwork/xwork-core/2.3.1. 2/xwork-core-2.3.1.2.pom (11 KB at 23.3 KB/sec) Downloading: http://uk.maven.org/maven2/ognl/ognl/3.0.4/ognl-3.0.4.pom Downloaded: http://uk.maven.org/maven2/ognl/ognl/3.0.4/ognl-3.0.4.pom (6 KB at 1 3.8 KB/sec) [WARNING] Invalid POM for ognl:ognl:jar:3.0.4, transitive dependencies (if any) will not be available, enable debug logging for more details Downloading: http://uk.maven.org/maven2/asm/asm/3.3/asm-3.3.pom Downloaded: http://uk.maven.org/maven2/asm/asm/3.3/asm-3.3.pom (264 B at 0.6 KB/ sec) Downloading: http://uk.maven.org/maven2/asm/asm-parent/3.3/asm-parent-3.3.pom Downloaded: http://uk.maven.org/maven2/asm/asm-parent/3.3/asm-parent-3.3.pom (5 KB at 9.9 KB/sec) Downloading: http://uk.maven.org/maven2/asm/asm-commons/3.3/asm-commons-3.3.pom Downloaded: http://uk.maven.org/maven2/asm/asm-commons/3.3/asm-commons-3.3.pom ( 415 B at 1.0 KB/sec) Downloading: http://uk.maven.org/maven2/asm/asm-tree/3.3/asm-tree-3.3.pom Downloaded: http://uk.maven.org/maven2/asm/asm-tree/3.3/asm-tree-3.3.pom (404 B at 1.0 KB/sec) Downloading: http://uk.maven.org/maven2/org/freemarker/freemarker/2.3.18/freemar ker-2.3.18.pom Downloaded: http://uk.maven.org/maven2/org/freemarker/freemarker/2.3.18/freemark er-2.3.18.pom (2 KB at 2.9 KB/sec) Downloading: http://uk.maven.org/maven2/org/apache/struts/struts2-core/2.3.1.2/s truts2-core-2.3.1.2.jar Downloaded: http://uk.maven.org/maven2/org/apache/struts/struts2-core/2.3.1.2/st ruts2-core-2.3.1.2.jar (757 KB at 100.6 KB/sec) Downloading: http://uk.maven.org/maven2/org/apache/struts/xwork/xwork-core/2.3.1 .2/xwork-core-2.3.1.2.jar Downloaded: http://uk.maven.org/maven2/org/apache/struts/xwork/xwork-core/2.3.1. 2/xwork-core-2.3.1.2.jar (606 KB at 61.6 KB/sec) Downloading: http://uk.maven.org/maven2/ognl/ognl/3.0.4/ognl-3.0.4.jar Downloaded: http://uk.maven.org/maven2/ognl/ognl/3.0.4/ognl-3.0.4.jar (223 KB at 89.6 KB/sec) Downloading: http://uk.maven.org/maven2/asm/asm/3.3/asm-3.3.jar Downloaded: http://uk.maven.org/maven2/asm/asm/3.3/asm-3.3.jar (43 KB at 22.9 KB /sec) Downloading: http://uk.maven.org/maven2/asm/asm-commons/3.3/asm-commons-3.3.jar Downloaded: http://uk.maven.org/maven2/asm/asm-commons/3.3/asm-commons-3.3.jar ( 38 KB at 31.4 KB/sec) Downloading: http://uk.maven.org/maven2/asm/asm-tree/3.3/asm-tree-3.3.jar Downloaded: http://uk.maven.org/maven2/asm/asm-tree/3.3/asm-tree-3.3.jar (21 KB at 35.6 KB/sec) Downloading: http://uk.maven.org/maven2/org/freemarker/freemarker/2.3.18/freemar ker-2.3.18.jar Downloaded: http://uk.maven.org/maven2/org/freemarker/freemarker/2.3.18/freemark er-2.3.18.jar (903 KB at 118.5 KB/sec) Downloading: http://uk.maven.org/maven2/commons-io/commons-io/2.0.1/commons-io-2 .0.1.jar Downloaded: http://uk.maven.org/maven2/commons-io/commons-io/2.0.1/commons-io-2. 0.1.jar (156 KB at 81.0 KB/sec) [INFO] Wrote settings to E:\struts2\Struts2Example\.settings\org.eclipse.jdt.cor e.prefs [INFO] Wrote Eclipse project for "Struts2Example" to E:\struts2\Struts2Example. [INFO] [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 42.871s [INFO] Finished at: Sat May 04 11:05:36 CST 2013 [INFO] Final Memory: 7M/19M [INFO] ------------------------------------------------------------------------ E:\struts2\Struts2Example>
执行以上命令就是通过maven下载相应的依赖jar包，然后生成了一下文件：
.classpath
.project
.setting
以上三个文件夹是执行mvn eclipse:eclipse -Dwtpversion=2.0命令得到的。
这里有一个问题，现在没有弄明白，导入到eclipse中后发现没有src/main/java目录，打开生成的.classpath文件在第一行加上
<classpathentry kind="src" path="src/main/java" including="**/*.java"/>
然后在相应的目录下创建java的文件夹即可；
加上这句话后.classpath文件的内容如下：
<?xml version="1.0" encoding="UTF-8"?> <classpath> <classpathentry kind="src" path="src/main/java" including="**/*.java"/> <classpathentry kind="src" path="src/main/resources" excluding="**/*.java"/> <classpathentry kind="output" path="target/classes"/> <classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/> <classpathentry kind="var" path="M2_REPO/junit/junit/3.8.1/junit-3.8.1.jar"/> <classpathentry kind="var" path="M2_REPO/org/apache/struts/struts2-core/2.3.1.2/struts2-core-2.3.1.2.jar"/> <classpathentry kind="var" path="M2_REPO/org/apache/struts/xwork/xwork-core/2.3.1.2/xwork-core-2.3.1.2.jar"/> <classpathentry kind="var" path="M2_REPO/commons-lang/commons-lang/2.5/commons-lang-2.5.jar"/> <classpathentry kind="var" path="M2_REPO/ognl/ognl/3.0.4/ognl-3.0.4.jar"/> <classpathentry kind="var" path="M2_REPO/asm/asm/3.3/asm-3.3.jar"/> <classpathentry kind="var" path="M2_REPO/asm/asm-commons/3.3/asm-commons-3.3.jar"/> <classpathentry kind="var" path="M2_REPO/asm/asm-tree/3.3/asm-tree-3.3.jar"/> <classpathentry kind="var" path="M2_REPO/org/freemarker/freemarker/2.3.18/freemarker-2.3.18.jar"/> <classpathentry kind="var" path="M2_REPO/commons-fileupload/commons-fileupload/1.2.2/commons-fileupload-1.2.2.jar"/> <classpathentry kind="var" path="M2_REPO/commons-io/commons-io/2.0.1/commons-io-2.0.1.jar"/> </classpath>
然后导入到eclipse中即可，导入后 的目录结构为：
如果把项目部署到tomcat上的时候，会出现 Tomcat version 6.0 only supports J2EE 1.2, 1.3, 1.4, and Java EE 5 Web modules
这个问题，解决方法；
找到路径E:\workspace\Struts2Example\.settings下面的org.eclipse.wst.common.project.facet.core文件
修改 <installed facet="jst.web" version="3.0"/> 为 <installed facet="jst.web" version="2.4"/> 即可；
修改后的文件为：
<?xml version="1.0" encoding="UTF-8"?> <faceted-project> <fixed facet="jst.java"/> <fixed facet="jst.web"/> <installed facet="jst.web" version="2.4"/> <installed facet="jst.java" version="1.7"/> </faceted-project>
然后再次进行部署就没有问题了。
首先创建：UserAction类：
package com.topwqp.action;
public class UserAction {
private String username;
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String execute(){
return "SUCCESS";
}
}
UserAction类很简单，不需要实现什么借口，或者继承什么类的， execute()方法是默认执行的方法，返回 SUCCESS是为了进行跳转转向。
login.jsp如下： 用到了struts2的标签库
<%@ page contentType="text/html; charset=UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<html>
<head></head>
<body>
<h1>Struts 2 Hello World Example</h1>
<s:form action="Welcome">
<s:textfield name="username" label="Username" />
<s:password name="password" label="Password" />
<s:submit />
</s:form>
</body>
</html>
<%@ page contentType="text/html; charset=UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<html>
<head></head>
<body>
<h1>Struts 2 Hello World Example</h1>
<h4>
Hello
<s:property value="username" />
</h4>
</body>
</html>
tomcat容器去加载web.xml文件，web.xml文件内容如下：
<!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>Struts 2 Web Application</display-name>
<filter>
<filter-name>struts2</filter-name>
<filter-class>
org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter
</filter-class>
</filter>
<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
</web-app>
web.xml回去加载struts.xml文件，其中配置了拦截的通配符路径。
struts.xml文件的内容如下：
其中package的name属性不起其他作用，仅仅是一个标记，namespace属性有重要作用，对应于webapp/user 这个目录的命名空间，所以当访问
http://localhost:8080/Struts2Example/user/Login.action时 就是访问对应的http://localhost:8080/Struts2Example/user/pages/login.jsp
两个访问效果是一样的。
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
<package name="user" namespace="/user" extends="struts-default">
<action name="Login">
<result>pages/login.jsp</result>
</action>
<action name="Welcome" class="com.topwqp.action.UserAction">
<result name="SUCCESS">pages/welcome.jsp</result>
</action>
</package>
</struts>
<action path="/Login" type="org.apache.struts.actions.ForwardAction" parameter="/pages/login.jsp"/>
跳转后如果提交就会提交到Welcome对应的action
路径为：http://localhost:8080/Struts2Example/user/Welcome.action
struts2的命名空间(namespace)对于模块化开发有很好的作用。
访问如下：
点击提交后页面挑战如下：
