DWR 简化 Ajax 的 portlet 间通-IT教育-计算机-珠峰网 www.my8848.com

DWR 简化 Ajax 的 portlet 间通

发布时间：2008/2/25 8:22:50 来源：xue.net 编辑：城市教育在线

现在有了后端和代理函数，可以开发 portlet 本身了。所有三个 portlet 都使用相同的代码基；惟一的区别是每个 portlet 使用的 JSP 的名称。

使用清单 6 中的代码创建一个新 portlet，并给它起名为 Orders:

清单 6. Orders.java

package interportletmessagingusingajax;
import java.io.*;
import javax.portlet.*;
public class Orders extends GenericPortlet {
  // JSP folder name
  public static final String JSP_FOLDER = "/interportletmessagingusingajax/jsp/";
  // JSP file name to be rendered on the view mode
  public static final String VIEW_JSP = "OrdersView";         
  public void init(PortletConfig config) throws PortletException{
    super.init(config);
  }
  public void doView(RenderRequest request, RenderResponse response) 
    throws PortletException, IOException {
    // Set the MIME type for the render response
    response.setContentType(request.getResponseContentType());
    // Invoke the JSP to render
    PortletRequestDispatcher rd = getPortletContext().getRequestDispatcher( 
      getJspFilePath(request, VIEW_JSP));
    rd.include(request,response);
    //this is workaround for portletsession sharing between
    //servlets and portlets
    //see http://weblogs.java.net/blog/wholder/archive/2005/02/session_session.html
    //and http://mail-archives.apache.org/mod_mbox/portals-pluto-dev/200502.mbox/%3Ca
    //2519328f3ba1d1eddfc33c924b6805d@umich.edu%3E
    //
    PortletRequestDispatcher rd2 = getPortletContext().getRequestDispatcher("/dwr/");
    rd2.include(request, response);
  }
  private static String getJspFilePath(RenderRequest request, String jspFile) {
    String markup = request.getProperty("wps.markup");
    if( markup == null )
      markup = getMarkup(request.getResponseContentType());
    return JSP_FOLDER+markup+"/"+jspFile+"."+getJspExtension(markup);
  }
  private static String getMarkup(String contentType) {
    if( "text/vnd.wap.wml".equals(contentType) )
      return "wml";
    return "html";
  }
  private static String getJspExtension(String markupName) {
    return "jsp";
  }
}

创建并打开 OrdersView.jsp（在 interportletmessagingusingajax/jsp/html 目录），并把清单 7 中的代码添加到它：

清单 7. OrdersView.jsp

<%@ page contentType="text/html" 
import="java.util.*,javax.portlet.*,interportletmessagingusingajax.*" %>
<%@taglib uri="http://java.sun.com/portlet" prefix="portlet" %>
<portlet:defineObjects/>
<jsp:include page="javascriptFunctions.jsp" />
<DIV style="margin: 6px">
<H4 style="margin-bottom: 3px">Orders</H4>
<table cellspacing="0" cellpadding="5" border="1">
<% db.MockupDB database= db.MockupDB.getInstance();
String[] orders=database.getOrders();
for(int i=0;i<orders.length;i++)
{
%>
<tr>
<td><%="000000000"+String.valueOf(i+1) %></td>
<td><a href="" onclick="return <portlet:namespace />sendOrderNr('<%=
  orders[i]%>');"><%=orders[i]%></a></td>
</tr>
<%
}
 %>
</table>
</DIV>

第二个 portlet 是 OrderDetailsPortlet.java。对这个 portlet 使用清单 6 中的代码，并把 VIEW_JSP 变量的值改成 OrdersDetailsPortletView.jsp。这个 JSP 的代码如清单 8 所示：

清单 8. OrdersDetailsPortletView.jsp

<%@ page contentType="text/html" 
import="java.util.*,javax.portlet.*,interportletmessagingusingajax.*" %>
<%@taglib uri="http://java.sun.com/portlet" prefix="portlet" %>
<portlet:defineObjects/>
<DIV style="margin: 6px">
<H4 style="margin-bottom: 3px">Order details</H4>
<table cellspacing="0" cellpadding="5" border="1">
<tr>
<th>Order number</th>
<th>Order details</th>
</tr>
<tr>
<%
String orderDetailsOrderNumber=(String)renderRequest.getPortletSession().getAttribute(
  "orderDetailsOrderNumber",PortletSession.APPLICATION_SCOPE);
String orderDetails=(String)renderRequest.getPortletSession().getAttribute(
  "orderDetails",PortletSession.APPLICATION_SCOPE);
if(orderDetailsOrderNumber==null)
{
orderDetailsOrderNumber="";
}
if(orderDetails==null)
{
orderDetails="";
}
%>
<td><div id="orderDetailsOrderNumber"><%=orderDetailsOrderNumber%>
</div></td>
<td><div id="orderDetails"><%=orderDetails%></div></td>
</tr>
</table>
</DIV>

第三个 portlet 是 CustomerDetailsPortlet.java。对这个 portlet 使用清单 6 中的代码，并把 VIEW_JSP 变量的值改成 CustomerDetailsPortletView.jsp。这个 JSP 的代码如清单 9 所示：

清单 9. CustomerDetailsPortletView.jsp

<%@ page contentType="text/html" 
import="java.util.*,javax.portlet.*,interportletmessagingusingajax.*" %>
<%@taglib uri="http://java.sun.com/portlet" prefix="portlet" %>
<portlet:defineObjects/>
<%
%>
<DIV style="margin: 6px">
<H4 style="margin-bottom: 3px">Customer details</H4>
<table cellspacing="0" cellpadding="5" border="1">
<tr>
<th>Order number</th>
<th>Customer details</th>
</tr>
<tr>
<%
String customerDetailsOrderNumber=
  (String)renderRequest.getPortletSession().getAttribute(
  "customerDetailsOrderNumber",PortletSession.APPLICATION_SCOPE);
String customerDetails=(String)renderRequest.getPortletSession().getAttribute(
  "customerDetails", PortletSession.APPLICATION_SCOPE);
if(customerDetailsOrderNumber==null)
{
customerDetailsOrderNumber="";
}
if(customerDetails==null)
{
customerDetails="";
}
%>
<td><div id="customerDetailsOrderNumber"><%=customerDetailsOrderNumber%>
</div></td>
<td><div id="customerDetails"><%=customerDetails%></div></td>
</tr>
</table>
</DIV>

示例应用程序现在准备好了。下一步是把 portlet 打包成 WAR 文件并在 Apache Jetspeed 门户中测试它。