配置数据源问题

Question

我在tomcat的server.xml中配置了数据源，在jsp中写了如下测试代码：<%@ page language="java" import="java.util.*" pageEncoding="GB2312"%>
<%@ page import="java.sql.*"%>
<%@ page import="javax.sql.*"%>
<%@ page import="javax.naming.*"%>
<%!
final String JNDINAME = "java:comp/env/jdbc/mldn" ;
%>
<%
Connection conn = null ;
try
{
Context ctx = new InitialContext() ;
DataSource ds = (DataSource)ctx.lookup(JNDINAME) ;
conn = ds.getConnection() ;
}
catch(Exception e)
{
System.out.println(e) ;
}
%>
<%=conn%>
<%
conn.close() ;
%>
在myeclipse中打开tmcat后运行出现如下问题：javax.naming.NameNotFoundException: Name jdbc is not bound in this Context
2008-11-23 14:47:04 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet jsp threw exception
java.lang.NullPointerException
at org.apache.jsp.index_jsp._jspService(index_jsp.java:77)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:174)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:874)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
at java.lang.Thread.run(Thread.java:595)

Answer 1

要在tomcat的context.xml裡面配置
<Resource name="jdbc/ownHome" auth="Container" type="javax.sql.DataSource" maxActive="10" maxIdle="3" maxWait="10000" username="sa" password="sa" driverClassName="com.microsoft.sqlserver.jdbc.SQLServerDriver" url="jdbc:sqlserver://localhost:1433;DatabaseName=ownHome" /> 

Answer 2

是你配置文件出错:web工程下的，WEB-INF下的web.xml添加这一段： <resource-ref>
    <description>DB Connection</description>
    <res-ref-name>JDBC/TestDB</res-ref-name>
    <res-type>javax.sql.DataSource</res-type>
    <res-auth>Container</res-auth>
  </resource-ref>相对应的jsp或者java代码应该为：DataSource ds = (DataSource) ctx.lookup("java:comp/env/JDBC/TestDB");
//数据库名楼主自己改
或者Context envCtx = (Context) ctx.lookup("java:comp/env");
DataSource ds = (DataSource) ctx.lookup("JDBC/TestDB");文章出处：http://www.diybl.com/course/1_web/webjs/2008224/101766.html
要是还不清楚，楼主参考以下上面的博客