內容提要：本文通過“用戶登錄”這個簡單功能，介紹struts2的標志（Tag）、Action、輸入校驗（Input Validation）以及本地化輸出（Localizing Output）。

開發環境：myeclipse5.0+eclipse3.2+jdk5.0+tomcat5.5+struts2+junit3.8（同實戰struts2——Hello World）

項目目錄結構：





















項目文件：
1. 首先我們為“用戶登錄”提供一個簡單入口
Welcome.jsp:

<% @?taglib?prefix = " s " ?uri = " /struts-tags " %>
< html >
???? < head >
???????? < title > Welcome </ title >
???????? < link? href ="<s:url?value=" /css/tutorial.css" /> "?rel="stylesheet"?type="text/css"?/>
???? </ head >
???? < body >
???????? < h3 >
????????????Commands
???????? </ h3 >
???????? < ul >
???????????? < li >
???????????????? < a? href ="<s:url?action=" Register" /> ">Register </ a >
???????????? </ li >
???????????? < li >
???????????????? < a? href ="<s:url?action=" Logon!input" /> ">Sign?On </ a >
???????????? </ li >
???????? </ ul >
???? </ body >
</ html >
這里，我們用到的是這句：
<a?href="<s:url?action="Logon!input"/>">Sign?On</a>
暫時先不理會“!input”的具體意義，接著往下看。

2. 登錄頁面
Logon.jsp:
<%@?taglib?prefix="s"?uri="/struts-tags"%>
<html>
????<head>
????????<title>Login</title>
????</head>
????<body>
????????<s:form?action="Logon">
????????????<s:textfield?label="User?Name"?name="username"?/>
????????????<s:password?label="Password"?name="password"?/>
????????????<s:submit?/>
????????</s:form>
????</body>
</html>

3. 接著，編寫與之對應的Action類。
com.cleversoft.struts2.demo.Logon.java:
package?com.cleversoft.struts2.demo;

import?com.opensymphony.xwork2.ActionSupport;

public?class?Logon?extends?ActionSupport?{

????/**
?????*?
?????*/
????private?static?final?long?serialVersionUID?=?-9039794122089833258L;

????public?String?execute()?throws?Exception?{

????????if?(isInvalid(getUsername()))
????????????return?INPUT;
????????if?(isInvalid(getPassword()))
????????????return?INPUT;
????????return?SUCCESS;
????}

????private?boolean?isInvalid(String?value)?{
????????return?(value?==?null?||?value.length()?==?0);
????}

????private?String?username;

????public?String?getUsername()?{
????????return?username;
????}

????public?void?setUsername(String?username)?{
????????this.username?=?username;
????}

????private?String?password;

????public?String?getPassword()?{
????????return?password;
????}

????public?void?setPassword(String?password)?{
????????this.password?=?password;
????}

}
需要注意這句：
????????if?(isInvalid(getUsername()))
????????????return?INPUT;
????????if?(isInvalid(getPassword()))
????????????return?INPUT;
????????return?SUCCESS;
如果用戶名和密碼均不為空的話，返回“success”，響應Menu.jsp頁面；否則返回“input”，響應Logon.jsp頁面。（見隨后struts.xml中的Action配置）
現在我們可以回想上面出現的“!input”。

4. 以上提到返回“input”，那接著看看與之對應的輸入校驗頁面。
Logon-validation.xml:
<!DOCTYPE?validators?PUBLIC?
"-//OpenSymphony?Group//XWork?Validator?1.0.2//EN"?
"http://www.opensymphony.com/xwork/xwork-validator-1.0.2.dtd">

<validators>
????<field?name="username">
????????<field-validator?type="requiredstring">
????????????<message>Username?is?required</message>
????????</field-validator>
????</field>
????<field?name="password">
????????<field-validator?type="requiredstring">
????????????<message>Password?is?required</message>
????????</field-validator>
????</field>
</validators>

需要注意的是，命名需要與與其對應的Action類匹配。

5. 最后需要進行Action配置。
struts.xml:

<!DOCTYPE?struts?PUBLIC
????"-//Apache?Software?Foundation//DTD?Struts?Configuration?2.0//EN"
????"http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
????<package?name="com.cleversoft.struts2.demo"
????????extends="struts-default">
????????<action?name="HelloWorld"
????????????class="com.cleversoft.struts2.demo.HelloWorld">
????????????<result>/HelloWorld.jsp</result>
????????</action>
????????<action?name="Welcome">
????????????<result>/Welcome.jsp</result>
????????</action>
????????<action?name="Menu">
????????????<result>/Menu.jsp</result>
????????</action>
????????<action?name="Logon!*"?method="{1}"
????????????class="com.cleversoft.struts2.demo.Logon">
????????????<result?type="redirect-action">Menu</result>
????????????<result?name="input">/Logon.jsp</result>
????????</action>
????</package>
</struts>
其中：
????????<action?name="Logon!*"?method="{1}"
????????????class="com.cleversoft.struts2.demo.Logon">
????????????<result?type="redirect-action">Menu</result>
????????????<result?name="input">/Logon.jsp</result>
????????</action>
“method="{1}"”等價于“method=input”，這是通配符式的寫法。

6. 其他
Menu.jsp:
<html>
????<head>
????????<title>Missing?Feature</title>
????</head>

????<body>
????????<p>
????????????This?feature?is?under?construction.?Please?try?again?in?the?next?interation.
????????</p>
????</body>
</html>

7. 運行
訪問http://localhost:8080/struts2/Welcome.action
運行結果：







登錄






輸入校驗









登錄成功










8. 本地化輸出
首先需要添加資源文件
package.properties:

requiredstring?=?$\{getText(fieldName)}?is?required.
password?=?Password
username?=?User?Name

接著需要修改Logon-validation.xml和Logon.jsp
Logon-validation.xml:

<!DOCTYPE?validators?PUBLIC?
"-//OpenSymphony?Group//XWork?Validator?1.0.2//EN"?
"http://www.opensymphony.com/xwork/xwork-validator-1.0.2.dtd">

<validators>
????<field?name="username">
????????<field-validator?type="requiredstring">
????????????<message?key="requiredstring"/>
????????</field-validator>
????</field>
????<field?name="password">
????????<field-validator?type="requiredstring">
????????????<message?key="requiredstring"/>
????????</field-validator>
????</field>
</validators>

Logon.jsp:

<%@?taglib?prefix="s"?uri="/struts-tags"%>
<html>
????<head>
????????<title>Login</title>
????</head>
????<body>
????????<s:form?action="Logon">
????????????<s:textfield?label="%{getText('username')}"?name="username"/>
????????????<s:password?label="%{getText('password')}"?name="password"?/>
????????????<s:submit?/>
????????</s:form>
????</body>
</html>



參考資料：
1. Getting Started
2. http://m.tkk7.com/max/category/16130.html

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