我运行自己的项目就出现这个问题！请问，怎么解决！谢谢了！

HTTP Status 500 -

--------------------------------------------------------------------------------

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: Exception in JSP: /index.jsp:27

24: </tr>
25: <tr>
26: <td height="19">
27: <sql:query var="gn" dataSource="${conn}">
28: Select top 6 id,news_Title from newsInfo where categoryId='100' order by id desc
29: </sql:query>
30: <table width="240" border="0">

Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:504)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:375)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:368)

root cause

javax.servlet.ServletException: Unable to get connection, DataSource invalid: "java.sql.SQLException: Network error IOException: Connection refused: connect"
org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:858)
org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:791)
org.apache.jsp.index_jsp._jspService(index_jsp.java:168)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:332)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:368)

root cause

javax.servlet.jsp.JspException: Unable to get connection, DataSource invalid: "java.sql.SQLException: Network error IOException: Connection refused: connect"
org.apache.taglibs.standard.tag.common.sql.QueryTagSupport.getConnection(QueryTagSupport.java:276)
org.apache.taglibs.standard.tag.common.sql.QueryTagSupport.doStartTag(QueryTagSupport.java:159)
org.apache.jsp.index_jsp._jspx_meth_sql_query_0(index_jsp.java:187)
org.apache.jsp.index_jsp._jspService(index_jsp.java:110)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:332)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:368)

note The full stack trace of the root cause is available in the Apache Tomcat/5.5.17 logs.