struts2其实就是为我们封装了servlet，简化了jsp跳转的复杂操作，并且提供了易于编写的标签，可以快速开发view层的代码。
过去，我们用jsp和servlet搭配，实现展现时，大体的过程是：
1 jsp触发action
2 servlet接受action,交给后台class处理
3 后台class跳转到其他的jsp，实现数据展现
现在有了struts2，实现过程变为
1 jsp出发action
2 struts2拦截请求，调用后台action
3 action返回结果，由不同的jsp展现数据
官网地址：http://struts.apache.org/
1.项目结构：
2.Maven pom 文件：
<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.xx</groupId>
<artifactId>struts</artifactId>
<packaging>war</packaging>
<version>1.0.0</version>
<name>struts Maven Webapp</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>utf-8</project.build.sourceEncoding>
<jdk.version>1.7</jdk.version>
</properties>
<dependencies>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.apache.struts</groupId>
<artifactId>struts2-core</artifactId>
<version>2.5.12</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.8.2</version>
</dependency>
</dependencies>
<build>
<finalName>struts</finalName>
<plugins>
<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>
<encoding>${project.build.sourceEncoding}</encoding>
</configuration>
</plugin>
<!-- tomcat7:run -->
<plugin>
<groupId>org.apache.tomcat.maven</groupId>
<artifactId>tomcat7-maven-plugin</artifactId>
<version>2.2</version>
<configuration>
<port>8080</port>
<path>/test</path>
<uriEncoding>UTF-8</uriEncoding>
<server>tomcat7</server>
</configuration>
</plugin>
</plugins>
</build>
</project>
3.web xml 文件：
<!-- Filters -->
<filter>
<filter-name>action2</filter-name>
<filter-class>org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>action2</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
4.struts xml 文件：
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.5//EN"
"http://struts.apache.org/dtds/struts-2.5.dtd">
<struts>
<!-- DIM 动态配置 -->
<constant name="struts.enable.DynamicMethodInvocation" value="true" />
<!-- 开发模式 -->
<constant name="struts.devMode" value="true"></constant>
<package name="default" extends="struts-default" namespace="/">
<action name="print" class="com.xx.action.HelloAction" method="hi">
<result>/hello.jsp</result>
</action>
</package>
</struts>
5.helloAction 文件：
package com.xx.action;
import com.opensymphony.xwork2.Action;
import com.opensymphony.xwork2.ActionSupport;
public class HelloAction extends ActionSupport{
public String hi(){
return Action.SUCCESS;
}
}
6.hello.jsp 文件：
<html>
<body>
<h2>Hello Struts!</h2>
</body>
</html>
7.运行：
tomcat7:run