Ajax servlet实现

之前用struts2.0做了异步请求,但总感觉有问题,请求次数太多后服务端就会挂起无响应了
正在解决这个问题

最开始用了struts.spring，hibernate三层来做，后来觉得hibernate可能会成为瓶颈，就直接改用jdbc做数据层，更改后貌似增大了请求次数

不过还是有问题，上论坛发了帖子，发现js出了点问题，做延时提交的时候没有清除定时器，导致请求几次仍然是提交几次，每次都给服务端造成了无端的压力
更改成

clearTimeout(time);  
time = setTimeout('passtoserver()',1000);//设置延时1s  

后实现了真正的延时请求

不过多次请求无响应的问题仍然存在，数据源是用的JNDI，是整个项目配的，我也管不了
看来还是得从程序入手了

猜测可能是struts的问题，于是乎想改用servlet直接做

不过问题来了，之前struts中的service对象是采用spring依赖注入的
有个struts2-spring-plugin.jar的支持，而直接用servlet的话就实现不了了

于是百度之后得到了答案(最近其实用google也多了，不过都是在百度不到的时候用的……呵呵)，通过ServletContext来或得ApplicationContext

//通过servletContext来拿ApplicationContext
	ServletContext   context=getServletContext();
	WebApplicationContext webContext = WebApplicationContextUtils.getRequiredWebApplicationContext(context); 

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

具体的意思我也还不明白，总之是拿到sessionfactory中的对象了

然后传递中文出现了问题，服务端response回的中文出现乱码了（又来了……）
通过对uri进行编码才得以解决，代码如下

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

		//通过servletContext来拿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");//异步传输过来的查询条件

		names = new ArrayList<String>();
		if(!start.equals(null)&&!start.equals(""))
		{
			List<TBasicinfo>  list = tbasicinfodao.getSearchInfo(start.trim());//根据查询条件查询
			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);
	}

页面上解析返回的数据也要改变一下，用

var decodede=decodeURI(request.responseText);

来实现

现在是把整个异步提交改成了Servlet+JDBC 不过请求次数多了还是会报错

之前出现的是thread.run() not availiable;

改用servlet实现异步提交后出现的问题
严重: 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 等宿老回来再说了~