dwr 推技术 demo

package com.test; import java.util.Collection; import java.util.Iterator; import java.util.LinkedList; import java.util.concurrent.locks.ReentrantLock; import org.directwebremoting.ScriptBuffer; import org.directwebremoting.ScriptSession; import org.directwebremoting.WebContext; import org.directwebremoting.WebContextFactory; import org.directwebremoting.proxy.dwr.Util; public class DWRHelper { private static LinkedList<Message> messages = new LinkedList<Message>(); private static ReentrantLock lock = new ReentrantLock(); //JDK5锁 public void addMessage(String text){ System.out.println("--enter--"); System.out.println(text); try{ lock.lock(); if(text!=null && text.trim().length()>0){ messages.addFirst(new Message(text)); if(messages.size()>10){ messages.removeLast(); } } }catch(Exception ex){ ex.printStackTrace(); }finally{ lock.unlock(); } //获得DWR上下文 WebContext webContext = WebContextFactory.get(); //获取当前页面URL，比如/ext3/test_tag.jsp String currentPage = webContext.getCurrentPage(); //当前脚本sessin ScriptSession scriptSession = webContext.getScriptSession(); //设置页面控件的值 Util util = new Util(scriptSession); util.setValue("text", "789"); //这里是清空页面输入框的值 //设置脚本sessin的属性值 scriptSession.setAttribute("uid", "cjm"); //获取脚本session的属性值 for(Iterator it=scriptSession.getAttributeNames();it.hasNext();){ String attrName = (String)it.next(); System.out.println(attrName + "=" + scriptSession.getAttribute(attrName)); } //获取所有浏览当前页面的脚本session Collection<ScriptSession> sessions = webContext.getScriptSessionsByPage(currentPage); Util utilAll = new Util(sessions); //执行客户端脚本 ScriptBuffer script = new ScriptBuffer(); script.appendScript(""); System.out.println(script); for(ScriptSession session: sessions){ session.addScript(script); } //更新这些脚本session的一些元素 utilAll.removeAllOptions("messages"); utilAll.addOptions("messages", messages, "id", "text"); } }