from [url]http://www.vaannila.com/struts-2/struts-2-example/struts-2-annotation-example-1.html[/url]
[b]这个例子当中需要注意的是:
1 必须引入struts2-convention-plugin-2.1.6包
2 WelcomeUser 类要放在 action命名的包下
3 welcome-user.jsp要放在web-inf/content目录下
4 具体请参见 Convention plug-in 运行原理
[/b]
[b]一搭建环境[/b]
jdk1.6 struts2.1.6 tomcat6.0
所需包
01.commons-fileupload-1.2.1
02.commons-io-1.3.2
03.commons-logging-1.1
04.freemarker-2.3.13
05.junit-3.8.1
06.ognl-2.6.11
07.spring-test-2.5.6
08.struts2-convention-plugin-2.1.6
09.struts2-core-2.1.6
10.xwork-2.1.2
[b]二代码[/b]
web.xml
<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5"> <display-name>Struts2_Annotations1</display-name> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> <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>
WelcomeUser.java
package com.test.action;import com.opensymphony.xwork2.ActionSupport;public class WelcomeUser extends ActionSupport{ private String userName; private String message; public String execute() { message = "Welcome" + userName; return SUCCESS; } public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } public String getMessage() { return message; } public void setMessage(String message) { this.message = message; }}
index.jsp在web-inf下
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><%@ taglib uri="/struts-tags" prefix="s"%><!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=UTF-8"><title>Annotations1</title></head><body><body><s:form action="welcome-user"> <s:textfield name="userName" label="User Name" /> <s:submit /></s:form></body></html>
welcome-user.jsp在web-inf/content目录下
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><!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=UTF-8"><title>Welcome User</title></head><body><h1>${message}</h1></body></html>
[b]三Convention plug-in 运行原理[/b]
the example works fine. Now lets see how the example works.
The Convention plug-in is the one which does everything in the background. The Convention plug-in does the following things.
* By default the Convention plug-in looks for the action classes inside the following packages strut, struts2, action or actions. Here our package name is com.vaannila.action. Any package that matches these names will be considered as the root package for the Convention plug-in.
* The action class should either implement com.opensymphony.xwork2.Action interface or the name of the action class should end with Action. Here we extend our WelcomeUser class from com.opensymphony.xwork2.ActionSupport which inturn implements com.opensymphony.xwork2.Action.
* The Convention plug-in uses the action class name to map the action URL. Here our action class name is WelcomeUser and the URL is welcome-user. The plug-in converts the camel case class name to dashes to get the request URL.
* Now the Convention plug-in knows which Action class to call for a particular request. The next step is to find which result to forward based on the return value of the execute method. By default the Convention plug-in will look for result pages in WEB-INF/content directory.
* Now the Convention plug-in knows where to look for results, but it doesn't know which file to display inside the content directory. The Convention plug-in finds this with the help of the result code returned by the Action class. If "success" is returned then the Convention plug-in will look for a file name welcome-user-success.jsp or welcome-user.jsp . It need not be a jsp file it can be even a velocity or freemaker files. If the result value is "input" it will look for a file name welcome-user-input.jsp or welcome-user-input.vm or welcome-user-input.ftl.
相关资源：struts2注解配置
