Portlet应用开发(JSR168)Part

1、Portlet 应用开发, Part 5Portlet 的 Session对象By Terry.liSpiritSeekerS本系列前一部分阐述了Portlet的Request和Response对象,本部分继续讲解Portlet中Session对象.及其与Servlet中Session对象的不同点.· Portlet Session中存取对象的作用范围 (Scope)Servlet中的Session属性和Portlet中的Session属性有一个非常大的不同点, 由于Portlet处于Portal中的缘故, Portlet的Session属性分为两种, 分别作用于不同的范围中:1.

2、Application Scope2. Portlet Scope这两者的区别在于:1) Application Scope类型的PortletSession中保存的对象对于同一个Portlet Application中的所有其它Portlet来说是可以被访问到的.2) Portlet Scope类型的PortletSession中保存的对象对于同一个Portlet Application中的所有其它Portlet来说是不可见的.但对于Portlet Application来说,其实它也是个Web Application , 因此不论是Application Scope也好,或者是Portle

3、t Scope也好,同样都属于HttpSession,因此都可以通过HttpSession 来访问.实际上Application Scope的Session就是HttpSession , 而Portlet Scope的Session 由于不可被其他Portlet访问, 它的session属性名称有它独特的存取方式, 如下:javax.portlet.p.<ID>?<ATTRIBUTE_NAME>其中ID是Portal/Portlet-Container生成用来唯一确定一个Portlet.Portlet Scope 的Session 使用以上的Attribute Name

4、 用以存取Session上绑定的属性. 我们所设制的Portlet Scope 的Session属性由Portlet容器自动转化成以上格式. 用以保证不被其它的Portlet访问到. 注: 以javax.portlet开头的Session属性名称是保留的,不可以用于Portlet的Session 属性名称.· Case study: 不同Scope Session的比较 以下我们将编码实现两个Portlet, 其中一个用来创建session属性的Portlet 和另一个用来验证session属性作用范围的Portlet. 用以验证Session属性的正确性.1. Portlet (P

5、ortletSessionExample1_GenerateSesssion.java) public void processAction(ActionRequest request,ActionResponse response)throws PortletException,IOExceptionString action=request.getParameter("ACTION");if(action.equals("ApplicationScope")PortletSession ps=request.getPortletSession();p

6、s.setAttribute("PortletSession.AS",action,PortletSession.APPLICATION_SCOPE);elsePortletSession ps=request.getPortletSession();ps.setAttribute("PortletSession.PS",action,PortletSession.PORTLET_SCOPE); 以上代码片段根据不同参数分别产生不同Scope的PortletSession 的属性 , 作用范围分别为Application 和 Portlet.2. Por

7、tlet (PortletSessionExample1_DisplaySession.java)这个Portlet调用一个JSP (jspShowSession.jsp) 来获得Portlet session和HttpSession, 并且示出来.3. JSP（view_portletsession1_generatesession.jsp）这个JSP将创建两个ActionURL , 分别用来产生两种PortletSession属性: <portlet:actionURL windowState="NORMAL" portletMode="view&quo

8、t; var="pu1"><portlet:param name="ACTION" value="ApplicationScope"/></portlet:actionURL><portlet:actionURL windowState="NORMAL" portletMode="view" var="pu2"><portlet:param name="ACTION" value="PortletS

9、cope"/></portlet:actionURL> 4. JSP (jspShowSession.jsp)取得以上创建的两个PortletSession 的属性值, 由Browser中可以看到只有Application Scope的Session 属性可以被获得.if(ps.getAttribute("PortletSession.AS",PortletSession.APPLICATION_SCOPE)!=null)app=ps.getAttribute("PortletSession.AS",PortletSessio

10、n.APPLICATION_SCOPE).toString();if(ps.getAttribute("PortletSession.PS",PortletSession.PORTLET_SCOPE)!=null)portlet=ps.getAttribute("PortletSession.PS",PortletSession.PORTLET_SCOPE).toString();以下代码将Httpsession中的所有属性全部列出: 可以看到PortletContainer是如何存取Portlet Scope类型的session属性的. <% H

11、ttpSession s=request.getSession();for (Enumeration e = s.getAttributeNames() ; e.hasMoreElements() ;) %><tr><td><%=e.nextElement()%></td></tr><% %> 将以上源代码编译后, 再通过Eclipse生成/更新Portlet的web.xml后, 将所有配置及相关文件部署后, 启动Tomcat. 在Browser中加载如下页面: Http:/localhost:8080/pluto/

12、portal , 可以看到如下的页面(图:5-1) 图:5-1单击PortletSession Example1 Page后可以看到如下两个Portlet 页面(图5-2)图:5-2上图中上边的一个Generate Portlet用来创建两个PortletSession属性,分别是Application Scope 和 Portlet Scope 类型. 下方的Display Portlet用以验证Session的作用范围.单击Application Scope Session, 可以看到如下页面(图5-3) 图5-3如上图，生成了一个Application Scope的属性，名称: Port

13、letSession.AS单击Portlet Scope Session, 可以看到如下页面(图5-4)图5-5生成了一个Portlet Scope Session属性，所以Display portlet 无法取得但是从HttpSession 可以看到又创建了一个session属性.Case study: Session的共享以上例子验证了Portlet中Session的作用范围, 可能在开发过程中经常需要有Popup页面的处理这个时候就无法使用Portlet, 但是可以使用Servlet或者是JSP, 以下这个例子是一个Portlet和Servlet的Session共享的应用 (或许是Tom

14、cat4的一个BUG), 我们将使用一个Portlet创建一个Application Scope的Session, 然后在一个Servlet中得到它. 1. Portlet (PortletSessionExample2_ShareSession.java)以下代码将创建一个application scope的Portlet Session: if(INF!=null)PortletSession ps=request.getPortletSession();ps.setAttribute("INF",INF,PortletSession.APPLICATION_SCOPE

15、); 2. JSP (jspLoginView.jsp) <%PortletSession ps = renderRequest.getPortletSession();String app=null;if(ps.getAttribute("INF",PortletSession.APPLICATION_SCOPE)!=null)app=ps.getAttribute("INF",PortletSession.APPLICATION_SCOPE).toString();%> <u><a style="cursor:

16、hand" onclick='window.open("/pluto/popup","a","width=400,height=330,scrollbars=1")'>Click here to Popup</a></u> <% %> 3. Servlet (PopupServlet.java) HttpSession se=request.getSession();Object info=se.getAttribute("INF"); 注: 由于

17、Tomcat下webapps目录下的pluto和portlets分别是两个web application, 所以将以上的PopupServlet配置到pluto目录下,而非portlets目录下.将以上源代码编译后, 再通过Eclipse生成/更新Portlet的web.xml后, 将所有配置及相关文件部署后, 启动Tomcat. 在Browser中加载如下页面: Http:/localhost:8080/pluto/portal , 可以看到如下的页面 单击PortletSession Example2 Page后可以看到如下页面(图5-6)图5-6单击 Click here to gene

18、rate a session , 后可以看到如下页面(图5-7) 图5-7单击 Click here to Popup , 后可以看到如下页面(图5-8)图5-8· 源代码及Portlet相关配置文件A. Session Example11. Portlet (PortletSessionExample1_GenerateSesssion.java)package portlets.portletsession;/* * author terry * * To change the template for this generated type comment go to * Wi

19、ndow&gt;Preferences&gt;Java&gt;Code Generation&gt;Code and Comments */import javax.portlet.*;import java.io.IOException;public class PortletSessionExample1_GenerateSesssion extends GenericPortletpublic void doView(RenderRequest request, RenderResponse response)throws PortletException

20、, IOExceptionresponse.setContentType("text/html");String jspName = getPortletConfig().getInitParameter("view");PortletRequestDispatcher rd = getPortletContext().getRequestDispatcher(jspName);rd.include(request, response); public void processAction(ActionRequest request,ActionResp

21、onse response)throws PortletException,IOExceptionString action=request.getParameter("ACTION");if(action.equals("ApplicationScope")PortletSession ps=request.getPortletSession();ps.setAttribute("PortletSession.AS",action,PortletSession.APPLICATION_SCOPE);elsePortletSessio

22、n ps=request.getPortletSession();ps.setAttribute("PortletSession.PS",action,PortletSession.PORTLET_SCOPE); 2. Portlet (PortletSessionExample1_DisplaySession.java) package portlets.portletsession;/* * author terry * * To change the template for this generated type comment go to * Window&

23、;gt;Preferences&gt;Java&gt;Code Generation&gt;Code and Comments */import javax.portlet.*;import java.io.IOException;public class PortletSessionExample1_DisplaySession extends GenericPortlet public void doView(RenderRequest request, RenderResponse response)throws PortletException, IOExcep

24、tion response.setContentType("text/html");String jspName = getPortletConfig().getInitParameter("view");PortletRequestDispatcher rd = getPortletContext().getRequestDispatcher(jspName);rd.include(request, response); 3. JSP (view_portletsession1_displaysession.jsp)<% page session

25、="false" %><% page import="javax.portlet.*"%><% page import="java.util.*"%><% taglib uri='/WEB-INF/tld/portlet.tld' prefix='portlet'%><portlet:defineObjects/><BR><h3>Display PortletSession and HttpSession Example<

26、;/h3><%PortletSession ps = renderRequest.getPortletSession();String app="NULL"String portlet="NULL"if(ps.getAttribute("PortletSession.AS",PortletSession.APPLICATION_SCOPE)!=null)app=ps.getAttribute("PortletSession.AS",PortletSession.APPLICATION_SCOPE).to

27、String();if(ps.getAttribute("PortletSession.PS",PortletSession.PORTLET_SCOPE)!=null)portlet=ps.getAttribute("PortletSession.PS",PortletSession.PORTLET_SCOPE).toString();%><b>PortletSession list:</b><table border=1><tr><td><b>Session Scope<

28、;/b></td><td><b>Attribute Name</b></td><td><b>Attribute Value</b></td></tr><tr><td>Application scope</td><td>PortletSession.AS</td><td><b><%=app%></b></td></tr><tr>&

29、lt;td>Portlet scope</td><td>PortletSession.PS</td><td><b><%=portlet%></b></td></tr></table><br><b>HttpSession list:</b><table border=1><tr><td><b>Attribute Name</b></td></tr><

30、;% HttpSession s=request.getSession(); for (Enumeration e = s.getAttributeNames() ; e.hasMoreElements() ;) %><tr><td><%=e.nextElement()%></td></tr><% %></table><BR><BR>4. JSP (view_portletsession1_generatesession.jsp)<% page session="f

31、alse" %><% page import="javax.portlet.*"%><% page import="java.util.*"%><% taglib uri='/WEB-INF/tld/portlet.tld' prefix='portlet'%><portlet:defineObjects/><portlet:actionURL windowState="NORMAL" portletMode="view&q

32、uot; var="pu1"><portlet:param name="ACTION" value="ApplicationScope"/></portlet:actionURL><portlet:actionURL windowState="NORMAL" portletMode="view" var="pu2"><portlet:param name="ACTION" value="Portle

33、tScope"/></portlet:actionURL><BR><h3>Generate PortletSession Example</h3><a href="<%=pu1%>">Application Scope Session</a><Br><a href="<%=pu2%>">Portlet Scope Session</a><Br><BR>B. Session Exampl

34、e21.Portlet (PortletSessionExample2_ShareSession.java)package portlets.portletsession;/* * author terry * * To change the template for this generated type comment go to * Window&gt;Preferences&gt;Java&gt;Code Generation&gt;Code and Comments */import javax.portlet.*;import java.io.IOE

35、xception;public class PortletSessionExample2_ShareSession extends GenericPortlet public void doView(RenderRequest request, RenderResponse response)throws PortletException, IOException response.setContentType("text/html");String jspName = getPortletConfig().getInitParameter("view"

36、);PortletRequestDispatcher rd = getPortletContext().getRequestDispatcher(jspName);rd.include(request, response); public void processAction(ActionRequest request, ActionResponse response) throws PortletException, java.io.IOException String INF=request.getParameter("INF"); if(INF!=null)Portl

37、etSession ps=request.getPortletSession();ps.setAttribute("INF",INF,PortletSession.APPLICATION_SCOPE); 2. Servlet (PopupServlet.java)package servlet;/* * author terry * * To change the template for this generated type comment go to * Window&gt;Preferences&gt;Java&gt;Code Generat

38、ion&gt;Code and Comments */import javax.servlet.http.*;import javax.servlet.*;import java.io.*;public class PopupServlet extends HttpServletpublic void doGet(HttpServletRequest request, HttpServletResponse response)throws IOException, ServletExceptionPrintWriter pw=response.getWriter();HttpSessi

39、on se=request.getSession();Object info=se.getAttribute("INF");if(info!=null)pw.println("<table border=1 bordercolor=black>");pw.println(" <tr>");pw.println(" <td><b>Attribute</b><td><td><b>Value</b></td> &

40、quot;);pw.println(" </tr>");pw.println(" <tr>");pw.println(" <td>INF<td><td>"+ info.toString() +"</td> ");pw.println(" </tr>");pw.println("</table>");elsepw.println("No session");C.

41、配置文件1. Portlet.xml <!- PortletSession Example -><!- PortletSession Example1 - GenerateSession -><portlet><description>PortletSession_Generator Example</description><portlet-name>PortletSession_GeneratorExample</portlet-name><display-name>PortletSession

42、_Generator Example</display-name><portlet-class>portlets.portletsession.PortletSessionExample1_GenerateSesssion</portlet-class><init-param><name>view</name><value>/fragments/portletsession/view_portletsession1_generatesession.jsp</value></init-param

43、><expiration-cache>-1</expiration-cache><supports><mime-type>text/html</mime-type><portlet-mode>VIEW</portlet-mode></supports><supported-locale>en</supported-locale><portlet-info><title>PortletSession_Generator Example</ti

44、tle><short-title>PortletSession_Generator</short-title><keywords>PortletSession_Generator</keywords></portlet-info></portlet><!- PortletSession Example1 - DisplaySession -><portlet><description>PortletSession_Display Example</description>

45、;<portlet-name>PortletSession_DisplayExample</portlet-name><display-name>PortletSession_Display Example</display-name><portlet-class>portlets.portletsession.PortletSessionExample1_DisplaySession</portlet-class><init-param><name>view</name><val

46、ue>/fragments/portletsession/view_portletsession1_displaysession.jsp</value></init-param><expiration-cache>-1</expiration-cache><supports><mime-type>text/html</mime-type><portlet-mode>VIEW</portlet-mode></supports><supported-locale>

47、;en</supported-locale><portlet-info><title>PortletSession_Display Example</title><short-title>PortletSession_Display</short-title><keywords>PortletSession_Display</keywords></portlet-info></portlet> 2. pageregistry.xml <!- PortletSession

48、 Example1 Page -> <fragment name="portletsessionpage1" type="page"> <navigation> <title>PortletSession Example1 Page</title> <description>PortletSession Example Page</description> </navigation> <fragment name="row1" type=&

49、quot;row"> <fragment name="col1" type="column"> <fragment name="p1" type="portlet"> <property name="portlet" value="10.40"/> </fragment> </fragment> </fragment> <fragment name="row2" type="row"> <fragment name="col1" type="column"> <fragment name="p1" type="portlet&q