Annotation is an alternatives of xml in a java application. It is a way to adding metadata facility to the application. for example interfaces and classes defines a type in an application and they can be used to several application elements. The annotation can be a compiler instruction that describes how to compile the code. The annotations are of many types that outline the data it contains. For Example @Action, @Override, @result, @Before, @Test etc. Every annotation type starts with the @ followed be a annotation name or interface name.
For Example to define an action Annotation you may write code as
@Action(value="/actionName",results={@Result(name=".....", location=".....")})ADS_TO_REPLACE_1
An annotation Based Hello World example is given below which takes user name as input and prints a message Hello plus user name.
HelloWorldAction.java
package net.roseindia.action; import org.apache.struts2.convention.annotation.Action; import org.apache.struts2.convention.annotation.Result; public class HelloWorldAction { private static final long serialVersionUID = 1L; String userName; String message; @Action(value = "/hello", results = { @Result(name = "success", location = "/jsp/successPage.jsp") }) public String execute() throws Exception { message = "Hello " + userName; return "success"; } public String getMessage() { return message; } public void setMessage(String message) { this.message = message; } public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } }
index.jspADS_TO_REPLACE_2
<%@ taglib prefix="s" uri="/struts-tags" %> <head> <title>Annotation Example</title> <style type="text/css">@import url(css/main.css);</style> <style> .errorMessage { color:green; } </style> <body bgcolor="#A3A3FF"> <center> <h2>Please Enter Your Name</h2> <s:form action="hello"> <s:textfield name="userName" label="Please Specy Your Name"/> <s:submit/> </s:form> </center> </body>
successPage.jsp
<%@ taglib prefix="s" uri="/struts-tags" %> <html> <head> <title>Annotation Example</title> </head> <body bgcolor="#9E9EE8"> <center> <h1>${message}</h1> </center> </body> </html>
struts.properties
struts.convention.result.path=/jsp
Download this example codeADS_TO_REPLACE_3
To See More Example on annotation follow the links given below
Hello World Example2ADS_TO_REPLACE_4
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