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This tutorial assumes you've completed the Hello World tutorial and have a working Hello_World_Struts2_Ant (or Hello_World_Struts2_Mvn) helloworld project. The example code for this tutorial, Using_Tags_Struts2_Ant or Using_Tags_Struts2_Mvn, is available on Google Code - http://code.google.com/p/struts2-examples/downloads/list. After downloading and unzipping the file, you'll have a folder named Using_Tags_Struts2_Ant (or Using_Tags_Struts2_Mvn). In that folder will be a README.txt file with instructions on how to build and run the example applicationusing_tags, is available for checkout from the Struts 2 GitHub repository at https://github.com/apache/struts-examples. The example projects use Maven to manage the artifact dependencies and to build the .war files. |
In the Hello World lesson, we added to the index.jsp a Struts 2 url tag to create a hyperlink to the hello.action. This tutorial will explore the url and other Struts 2 tags further.
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A very common use case in web applications is linking to other pages. In the Hello World tutorial we added to index.jsp a link to the hello.action using the Struts 2 url tag. Please refer to the url documentation for more information about the url tag.
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html| language | html | | title | index.jsp |
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| borderStyle | solid |
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<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@ taglib prefix="s" uri="/struts-tags" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Basic Struts 2 Application - Welcome</title>
</head>
<body>
<h1>Welcome To Struts 2!</h1>
<p><a href="<s:url action='hello'/>">Hello World</a></p>
</body>
</html>
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Examine the struts.xml configuration in the Hello World tutorial and you will find this:
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| htmlxmlhtml |
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| xml |
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| title | struts.xml |
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| borderStyle | solid |
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<action name="hello" class="org.apache.struts.helloworld.action.HelloWorldAction" method="execute">
<result name="success">/HelloWorld.jsp</result>
</action>
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| html |
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| html |
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| title | url tag with param |
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<s:url action="hello" var="helloLink">
<s:param name="userName">Bruce Phillips</s:param>
</s:url>
<p><a href="${helloLink}">Hello Bruce Phillips</a></p>
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Add the following markup to index.jsp after the Hello Bruce Phillips link.
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| title | Struts 2 Form |
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<p>Get your own personal hello by filling out and submitting this form.</p>
<s:form action="hello">
<s:textfield name="userName" label="Your name" />
<s:submit value="Submit" />
</s:form>
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| html |
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| html |
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| title | Struts Form Tags Converted To HTML |
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<form id="hello" name="hello" action="/Using_Tags_Struts2_Mvn/hello.action;jsessionid=3471d76027b5342cab44f297b567" method="post">
<table class="wwFormTable">
<tr>
<td class="tdLabel"><label for="hello_userName" class="label">Your name:</label></td>
<td><input type="text" name="userName" value="" id="hello_userName"/></td>
</tr>
<tr>
<td colspan="2"><div align="right"><input type="submit" id="hello_0" value="Submit"/>
</div></td>
</tr>
</table>
</form>
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In the Hello World tutorial's example application on JSP HelloWorld.jsp was this code:
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| title | Struts Property Tag |
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<s:property value="messageStore.message" />
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One very useful feature of the Struts 2 property tag is that it will automatically convert the most common data types (int, double, boolean) to their String equivalents. To demonstrate this feature let's add a static int variable to class HelloWorldAction.
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| JAVAjavaJAVA |
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| java |
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| title | Add Static Field |
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private static int helloCount = 0;
public int getHelloCount() {
return helloCount;
}
public void setHelloCount(int helloCount) {
HelloWorldAction.helloCount = helloCount;
}
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Each time the execute method is called we'll increase helloCount by 1. So add this code to the execute method of class HelloWorldAction.
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| JAVAjavaJAVA |
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| java |
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| title | Increase helloCount |
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helloCount++;
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Whenever a user clicks one of the links on page index.jsp (or submits the form), method execute of class HelloWorldAction will be run and the static field helloCount will be increased by one.
To include the value of the helloCount attribute in the HelloWorld.jsp we can use the Struts 2 property tag. Add the following to HelloWorld.jsp after the h2 tag.
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| title | Use Property Tag To Display helloCount Value |
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<p>I've said hello <s:property value="helloCount" /> times!</p>
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If the value returned by the get method is an object, then the property tag will cause Struts 2 to call the object's toString method. Of course, you should always override Class Object's toString method in your model classes. Add the following toString method to the MessageStore class:
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| JAVAjavaJAVA |
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| java |
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| title | Add toString Method To Class MessageStore |
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public String toString() {
return message + " (from toString)";
}
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Add the following to HelloWorld.jsp
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| HTMLhtmlHTML |
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| html |
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| title | Using Property Tag to Call toString |
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<p><s:property value="messageStore" /></p>
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