How To Create A Struts 2 Web Application
- Java Requirements
- Our First Application
- Create Struts 2 Web Application Using Maven To Manage Artifacts and To Build The Application
- Getting Help
This tutorial walks through installing the framework and creating a simple application.
While the Struts 2 framework is simple to use, creating non-trivial applications assumes a working knowledge of many J2EE technologies, including:
- Java
- Filters, JSP, and Tag Libraries
- JavaBeans
- HTML and HTTP
- Web Containers (such as Tomcat)
- XML
For more about supporting technologies, see the Key Technologies Primer.
Java Requirements
Struts 2 requires Servlet API 2.4 or higher, JSP 2.0 or higher, and Java 7 or higher.
Our First Application
To get started using Struts 2 we will create a web application using Maven to manage the artifact dependencies. You can checkout all the example applications from the Struts 2 GitHub repository at struts-examples.
Create Struts 2 Web Application Using Maven To Manage Artifacts and To Build The Application
This tutorial assumes you know how to create a Java web application that uses Maven to manage artifacts and build the web application archive (war) file.
Step 1 - Create A Java Web Application
In your Java IDE create a Java web application with a project name of basic_struts that follows the standard Maven
project folder structure. In your pom.xml
include the following:
pom.xml build node
<build>
<finalName>basic-struts</finalName>
</build>
to run the application using maven, add the jetty maven-plugin to your pom.xml
pom.xml jetty plugin
<build>
...
<plugins>
<plugin>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-maven-plugin</artifactId>
<version>9.4.7.v20170914</version>
<configuration>
<webApp>
<contextPath>/${build.finalName}</contextPath>
</webApp>
<stopKey>CTRL+C</stopKey>
<stopPort>8999</stopPort>
<scanIntervalSeconds>10</scanIntervalSeconds>
<scanTargets>
<scanTarget>src/main/webapp/WEB-INF/web.xml</scanTarget>
</scanTargets>
</configuration>
</plugin>
</plugins>
</build>
The above plugin will enable you to run the application using mvn jetty:run
Step 2 - Add index.jsp
Our next step is to add a simple index.jsp
to this web application. Create an index.jsp
under src/main/webapp
with a title of Basic Struts 2 Application - Welcome and in the body add an h1 heading of Welcome to Struts 2!
index.jsp
<!DOCTYPE html>
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<html>
<head>
<meta charset="UTF-8">
<title>Basic Struts 2 Application - Welcome</title>
</head>
<body>
<h1>Welcome To Struts 2!</h1>
</body>
</html>
Run mvn jetty:run
to run the application.
In a web browser go to http://localhost:8080/basic-struts/index.jsp. You should see the following:
Step 3 - Add Struts 2 Jar Files To Class Path
Now that we know we have a working Java web application, lets add the minimal required Struts 2 framework Jar files
to our web application’s class path. In pom.xml
add the following dependency node:
pom.xml dependency node
<dependency>
<groupId>org.apache.struts</groupId>
<artifactId>struts2-core</artifactId>
<version>X.X.X.X</version>
</dependency>
Of course replace the X.X.X.X with the current Struts 2 version. Maven will get the struts2-core
jar and the other jar
files struts2-core requires (transitive dependencies).
Beginning with Struts version 2.2.3 you do not need to specify a separate dependency node for javassist.
Step 4 - Add Logging
To see what’s happening under the hood, the example application for this tutorial uses log4j2. You’ll need to add a dependency node for log4j2 to the pom:
pom.xml log4j dependency node
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.8.2</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-api</artifactId>
<version>2.8.2</version>
</dependency>
Using both log4j-core
and log4j-api
allows to use the latest version of Log4j2 without a clash with version provided by the framework. Setup a log4j2.xml
configuration in the src/main/resources
folder which contains the following
log4j2.xml
<?xml version="1.0" encoding="UTF-8"?>
<Configuration>
<Appenders>
<Console name="STDOUT" target="SYSTEM_OUT">
<PatternLayout pattern="%d %-5p [%t] %C{2} (%F:%L) - %m%n"/>
</Console>
</Appenders>
<Loggers>
<Logger name="com.opensymphony.xwork2" level="debug"/>
<Logger name="org.apache.struts2" level="debug"/>
<Root level="warn">
<AppenderRef ref="STDOUT"/>
</Root>
</Loggers>
</Configuration>
Note the above log4j2 configuration specifies the console as the log target.
Step 5 - Add Struts 2 Servlet Filter
To enable the Struts 2 framework to work with your web application you need to add a Servlet filter class and filter
mapping to web.xml
. Below is the filter and filter-mapping nodes you should add to web.xml
.
web.xml Servlet Filter
<filter>
<filter-name>struts2</filter-name>
<filter-class>org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
For more information about configuring the deployment descriptor for Struts 2 see web.xml
. Note the url-pattern node
value is /*
meaning the Struts 2 filter will be applied to all URLs for this web application.
Step 6 - Create struts.xml
Struts 2 can use either an XML configuration file or annotations (or both) to specify the relationship between a URL,
a Java class, and a view page (such as index.jsp
). For our basic Struts 2 application, we’ll use a minimal xml
configuration. Note the file name is struts.xml
and it should be in the src/main/resources
folder (struts.xml
must be on the web application’s root class path).
struts.xml
<?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>
<constant name="struts.devMode" value="true" />
<package name="basicstruts2" extends="struts-default">
<action name="index">
<result>/index.jsp</result>
</action>
</package>
</struts>
This minimal Struts 2 configuration file tells the framework that if the URL ends in index.action
to redirect
the browser to index.jsp
.
For more information about the struts.xml configuration file see struts.xml
.
Step 7 - Build and Run the Application
Run mvn jetty:run
to run the web-application using the jetty maven-plugin.
View the console where you should see numerous debug messages that tell you the Struts 2 framework is being included in the basic-struts2
web application.
Open a web browser and go to http://localhost:8080/basic-struts/index.action
(note that’s index.action
not index.jsp
at the end of the URL). You should see the same web page as when going to
http://localhost:8080/basic-struts/index.jsp. View the log
messages written to the console and you should find several that discuss index.action
and index.jsp
:
Struts 2 Log Messages
...
2017-04-17 11:16:01,084 DEBUG [qtp1723848804-22] xwork2.DefaultActionProxy (DefaultActionProxy.java:89) - Creating an DefaultActionProxy for namespace [/] and action name [index]
...
2017-04-17 11:16:01,172 DEBUG [qtp1723848804-22] result.ServletDispatcherResult (ServletDispatcherResult.java:131) - Forwarding to location: /index.jsp
...
Getting Help
The Struts 2 user mailing list is an excellent place to get help. If you are having a problem getting this Basic Struts 2 application to work search the Struts 2 mailing list. If you don’t find an answer to your problem, post a question on the mailing list.
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