请问这个错误什么意思
请问这个错误什么意思，怎么解决这个问题？希望各位大虾告诉小弟。。。
com.mysql.jdbc.exceptions.MySQLNonTransientConnectionException:   Operation   not   allowed   on   closed   connection
at   com.mysql.jdbc.SQLError.createSQLException(SQLError.java:888)
at   com.mysql.jdbc.Connection.getIO(Connection.java:3587)
at   com.mysql.jdbc.PreparedStatement.fillSendPacket(PreparedStatement.java:1646)
at   com.mysql.jdbc.PreparedStatement.fillSendPacket(PreparedStatement.java:1622)
at   com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1332)
at   com.nc138.bean.Doc.queryDocByID(Doc.java:113)
at   org.apache.jsp.run_005fwords_jsp._jspService(run_005fwords_jsp.java:59)
at   org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
at   javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at   org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:334)
at   org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
at   org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
at   javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at   org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
at   org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at   org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:672)
at   org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:574)
at   org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:499)
at   org.apache.jasper.runtime.JspRuntimeLibrary.include(JspRuntimeLibrary.java:966)
at   org.apache.jsp.index_jsp._jspService(index_jsp.java:166)
at   org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
at   javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at   org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:334)
at   org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
at   org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
at   javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at   org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
at   org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at   org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at   org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
at   org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
at   org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
at   org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
at   org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
at   org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:199)
at   org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:282)
at   org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:767)
at   org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:697)
at   org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:8