Ajax servlet實現

之前用struts2.0做了異步請求,但總感覺有問題,請求次數太多後服務端就會掛起無響應了
正在解決這個問題

最開始用了struts.spring，hibernate三層來做，後來覺得hibernate可能會成爲瓶頸，就直接改用jdbc做數據層，更改後貌似增大了請求次數

不過還是有問題，上論壇發了帖子，發現js出了點問題，做延時提交的時候沒有清除定時器，導致請求幾次仍然是提交幾次，每次都給服務端造成了無端的壓力
更改成

clearTimeout(time);  
time = setTimeout('passtoserver()',1000);//設置延時1s  

後實現了真正的延時請求

不過多次請求無響應的問題仍然存在，數據源是用的JNDI，是整個項目配的，我也管不了
看來還是得從程序入手了

猜測可能是struts的問題，於是乎想改用servlet直接做

不過問題來了，之前struts中的service對象是採用spring依賴注入的
有個struts2-spring-plugin.jar的支持，而直接用servlet的話就實現不了了

於是百度之後得到了答案(最近其實用google也多了，不過都是在百度不到的時候用的……呵呵)，通過ServletContext來或得ApplicationContext

//通過servletContext來拿ApplicationContext
	ServletContext   context=getServletContext();
	WebApplicationContext webContext = WebApplicationContextUtils.getRequiredWebApplicationContext(context); 

	TBasicinfoDAO tbasicinfodao =(TBasicinfoDAOImpl) webContext.getBean("tbasicinfodao");

具體的意思我也還不明白，總之是拿到sessionfactory中的對象了

然後傳遞中文出現了問題，服務端response回的中文出現亂碼了（又來了……）
通過對uri進行編碼才得以解決，代碼如下

public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		//通過servletContext來拿ApplicationContext
		[color=red]ServletContext   context=getServletContext();
		WebApplicationContext webContext = WebApplicationContextUtils.getRequiredWebApplicationContext(context); [/color]

		TBasicinfoDAO tbasicinfodao =(TBasicinfoDAOImpl) webContext.getBean("tbasicinfodao");

		response.setContentType("text/html");
		PrintWriter out = response.getWriter();

		String start=request.getParameter("start");//異步傳輸過來的查詢條件

		names = new ArrayList<String>();
		if(!start.equals(null)&&!start.equals(""))
		{
			List<TBasicinfo>  list = tbasicinfodao.getSearchInfo(start.trim());//根據查詢條件查詢
			JSONObject option = new JSONObject();
			try {
					TBasicinfo tmp=null;
					String encode=null;
					for(int i=0; i<list.size(); i++)
					{
						tmp=new TBasicinfo();
						tmp=list.get(i);
						 option.put("value", tmp.getEmpno());

						// java.net.URLEncoder.encode(tmp.getName(), "gbk");

						option.put("name", [color=red]java.net.URLEncoder.encode(tmp.getName(), "utf-8"));[/color]
						 ///option.put("name", tmp.getName());
						 option.put("pinyin",tmp.getNamespell());
						 names.add(option.toString());
					}
			} catch (Exception e) {
				e.printStackTrace();
			}
			[color=red]response.setHeader("Charset","gbk");
			response.setCharacterEncoding("gbk");[/color]

		}
		out.print(names);
	}

頁面上解析返回的數據也要改變一下，用

var decodede=decodeURI(request.responseText);

來實現

現在是把整個異步提交改成了Servlet+JDBC 不過請求次數多了還是會報錯

之前出現的是thread.run() not availiable;

改用servlet實現異步提交後出現的問題
嚴重: Servlet.service() for servlet FindTableValueServlet threw exception
org.hibernate.exception.GenericJDBCException: Cannot open connection
	at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:103)
	at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:91)
	at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
	at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:29)
	at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:420)
	at org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:144)
	at org.hibernate.jdbc.AbstractBatcher.prepareQueryStatement(AbstractBatcher.java:105)
	at org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1561)
	at org.hibernate.loader.Loader.doQuery(Loader.java:661)
	at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:224)
	at org.hibernate.loader.Loader.doList(Loader.java:2145)
	at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2029)
	at org.hibernate.loader.Loader.list(Loader.java:2024)
	at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:375)
	at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:308)
	at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:153)
	at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1106)
	at org.hibernate.impl.QueryImpl.list(QueryImpl.java:79)
	at edu.bit.cctv.hr.dao.impl.Ttwz_stacontDAOImpl.getStatisticItem(Ttwz_stacontDAOImpl.java:22)
	at edu.bit.cctv.generalsearch.service.impl.DispViewServiceImpl.dispStatisticItem

(DispViewServiceImpl.java:59)
	at edu.bit.cctv.generalsearch.action.FindTableValueServlet.doPost(FindTableValueServlet.java:92)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:413)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.struts2.dispatcher.ActionContextCleanUp.doFilter(ActionContextCleanUp.java:99)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:261)
	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
	at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:581)
	at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
	at java.lang.Thread.run(Unknown Source)
Caused by: org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot get a connection, pool error Timeout waiting for 

idle object
	at org.apache.tomcat.dbcp.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:104)
	at org.apache.tomcat.dbcp.dbcp.BasicDataSource.getConnection(BasicDataSource.java:880)
	at org.springframework.orm.hibernate3.LocalDataSourceConnectionProvider.getConnection

(LocalDataSourceConnectionProvider.java:81)
	at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:417)
	... 36 more
Caused by: java.util.NoSuchElementException: Timeout waiting for idle object
	at org.apache.tomcat.dbcp.pool.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:825)
	at org.apache.tomcat.dbcp.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:96)
	... 39 more

搞不定了 等宿老回來再說了~