struts标签的使用
strusts标签挺好用的，但是在使用过程中可能会遇到一些很莫名的问题。这里罗列一些出来，会持续更新... last update：2009/5/5
- 如果想在Struts标签中的 value属性中添加变量，不可以使用struts标签嵌套。因struts不支持标签嵌套，可采用EL来解决该问题。例如：
<logic:equal name="charge" property="num" value="${business.num}">
......
</logic:equal>
......
</logic:equal>
将Struts 应用程序移植到 JSF
清单 5. 在 web.xml 中声明 FacesServlet
<!-- JavaServer Faces Servlet Configuration -->
<servlet>
<servlet-name>faces</servlet-name>
<servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<!-- JavaServer Faces Servlet Mapping -->
<servlet-mapping>
<servlet-name>faces</servlet-name>
<url-pattern>/faces/*</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>faces</servlet-name>
<servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<!-- JavaServer Faces Servlet Mapping -->
<servlet-mapping>
<servlet-name>faces</servlet-name>
<url-pattern>/faces/*</url-pattern>
</servlet-mapping>
<%@ taglib uri="/WEB-INF/struts-tiles.tld" prefix="tiles" %>
<%@ taglib uri="http://jakarta.apache.org/struts/tags-faces"prefix="s" %>
<!-- Layout component parameters: header, menu, body, footer -->
<s:html>
<head>
<title> <tiles:getAsString name="title"/></title>
<s:base/>
</head>
<body>
<TABLE border="0" width="100%" cellspacing="5">
<tr>
<td><tiles:insert attribute="header"/></td>
</tr>
<tr>
<td><tiles:insert attribute="body"/></td>
</tr>
<tr><td><hr></td></tr>
<tr>
<td><tiles:insert attribute="footer" /></td>
</tr>
</TABLE>
</body>
</s:html>
<%@ taglib uri="http://jakarta.apache.org/struts/tags-faces"prefix="s" %>
<!-- Layout component parameters: header, menu, body, footer -->
<s:html>
<head>
<title> <tiles:getAsString name="title"/></title>
<s:base/>
</head>
<body>
<TABLE border="0" width="100%" cellspacing="5">
<tr>
<td><tiles:insert attribute="header"/></td>
</tr>
<tr>
<td><tiles:insert attribute="body"/></td>
</tr>
<tr><td><hr></td></tr>
<tr>
<td><tiles:insert attribute="footer" /></td>
</tr>
</TABLE>
</body>
</s:html>
<!-- Master Layout definition -->
<definition name="foobar.master-layout"
path="/faces/layout/MasterLayout.jsp">
<put name="title" value="Welcome to Foo Bar Travels" />
<put name="header" value="/faces/common/header.jsp" />
<put name="footer" value="/faces/common/footer.jsp" />
<put name="body" value="" />
</definition>
<!-- Definition for Flight Search Page -->
<definition name="/foobar.flight-search"
extends="foobar.master-layout">
<put name="body" value="/faces/FlightSearch.jsp" />
</definition>
<definition name="foobar.master-layout"
path="/faces/layout/MasterLayout.jsp">
<put name="title" value="Welcome to Foo Bar Travels" />
<put name="header" value="/faces/common/header.jsp" />
<put name="footer" value="/faces/common/footer.jsp" />
<put name="body" value="" />
</definition>
<!-- Definition for Flight Search Page -->
<definition name="/foobar.flight-search"
extends="foobar.master-layout">
<put name="body" value="/faces/FlightSearch.jsp" />
</definition>
RequestDispatcher rd = null;
Tree tree = context.getTree();
String requestURI = context.getTree().getTreeId();
rd = request.getRequestDispatcher(requestURI);
/** If the response is committed, include the resource **/
if( !response.isCommitted() ) {
rd.forward(request, context.getServletResponse());
}
else {
rd.include(request, context.getServletResponse());
}
Tree tree = context.getTree();
String requestURI = context.getTree().getTreeId();
rd = request.getRequestDispatcher(requestURI);
/** If the response is committed, include the resource **/
if( !response.isCommitted() ) {
rd.forward(request, context.getServletResponse());
}
else {
rd.include(request, context.getServletResponse());
}
//Get the LifecycleFactory from the Factory Finder
LifecycleFactory factory = (LifecycleFactory)
FactoryFinder.getFactory("javax.faces.lifecycle.LifecycleFactory");
//Get the context param from web.xml
String lifecycleID =
getServletContext().getInitParameter("javax.faces.lifecycle.LIFECYCLE_ID");
//Get the Lifecycle Implementation
Lifecycle lifecycle = factory.getLifecycle(lifeCycleID);
LifecycleFactory factory = (LifecycleFactory)
FactoryFinder.getFactory("javax.faces.lifecycle.LifecycleFactory");
//Get the context param from web.xml
String lifecycleID =
getServletContext().getInitParameter("javax.faces.lifecycle.LIFECYCLE_ID");
//Get the Lifecycle Implementation
Lifecycle lifecycle = factory.getLifecycle(lifeCycleID);
//Get the LifecycleFactory from the Factory Finder
LifecycleFactory factory = (LifecycleFactory)
FactoryFinder.getFactory("javax.faces.lifecycle.LifecycleFactory");
//Create a new instance of Lifecycle implementation -
//com.sun.faces.lifecycle.LifecycleImpl
//According to the documentation, factory.getLifecycle("STFLifecycle")
//should work, but JSF-RI has a defect.
//Hence this workaround of creating a RI class explicitly.
LifecycleImpl stfLifecycleImpl = new LifecycleImpl();
//Create a new instance of our STFViewHandler and set it on the Lifecycle
stfLifecycleImpl.setViewHandler(new STFViewHandlerImpl());
//Register the new lifecycle with the factory with a unique
//name "STFLifecycle"
factory.addLifecycle("STFLifecycle", stfLifecycleImpl);
LifecycleFactory factory = (LifecycleFactory)
FactoryFinder.getFactory("javax.faces.lifecycle.LifecycleFactory");
//Create a new instance of Lifecycle implementation -
//com.sun.faces.lifecycle.LifecycleImpl
//According to the documentation, factory.getLifecycle("STFLifecycle")
//should work, but JSF-RI has a defect.
//Hence this workaround of creating a RI class explicitly.
LifecycleImpl stfLifecycleImpl = new LifecycleImpl();
//Create a new instance of our STFViewHandler and set it on the Lifecycle
stfLifecycleImpl.setViewHandler(new STFViewHandlerImpl());
//Register the new lifecycle with the factory with a unique
//name "STFLifecycle"
factory.addLifecycle("STFLifecycle", stfLifecycleImpl);
您可以看到
lifecycleId 硬编码为 STFLifecycle 。实际上不是这样。当您回过头分析 清单 9时就会清楚。 FacesServlet 从在 web.xml 文件中声明的上下文参数中得到名为 javax.faces.lifecycle.LIFECYCLE_ID 的 lifecycle ID，如下所示： <context-param>
<param-name>javax.faces.lifecycle.LIFECYCLE_ID</param-name>
<param-value>STFLifecycle</param-value>
</context-param>
<param-name>javax.faces.lifecycle.LIFECYCLE_ID</param-name>
<param-value>STFLifecycle</param-value>
</context-param>
<listener>
<listener-class>foo.bar.stf.application.STFContextListener
</listener-class>
</listener>
<listener-class>foo.bar.stf.application.STFContextListener
</listener-class>
</listener>
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