[英]javax.naming.NameNotFoundException : Unable to connect to derby database
I am trying to connect to derby
database while using Tomcat
. 我正在尝试使用
Tomcat
连接到derby
数据库。 I try to do this through a servlet. 我尝试通过servlet做到这一点。 But i am unable to connect and get the following exception :
但是我无法连接并得到以下异常:
javax.naming.NameNotFoundException: Name jdbc is not bound in this Context
at org.apache.naming.NamingContext.lookup(NamingContext.java:803)
at org.apache.naming.NamingContext.lookup(NamingContext.java:159)
at org.apache.naming.SelectorContext.lookup(SelectorContext.java:158)
at javax.naming.InitialContext.lookup(InitialContext.java:392)
at servlets.servlet_1.doGet(servlet_1.java:21) //---> I have marked this line in the below servlet
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:929)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:405)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:964)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:515)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:885)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
at java.lang.Thread.run(Thread.java:619)
when the following servlet gets run : 当以下servlet运行时:
package servlets;
import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.servlet.http.*;
import javax.servlet.*;
import javax.sql.DataSource;
public class servlet_1 extends HttpServlet{
@Override
public void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException {
try {
// String queryString = request.getQueryString();
Context context = new InitialContext();
DataSource ds = (DataSource)context.lookup("jdbc/PollDatasource");
Connection connection = ds.getConnection(); // ----> LINE 21
String sqlQuery = "select * from PollResult";
PreparedStatement statement = connection.prepareStatement(sqlQuery);
ResultSet set = statement.executeQuery();
System.out.println("after the final statement");
}catch(Exception exc) {
exc.printStackTrace();
}
}
} }
Why do i get this exception ? 为什么会出现此异常?
I added the following lines in context.xml
of Tomcat
: 我在
Tomcat
context.xml
中添加了以下几行:
<Resource name="jdbc/PollDatasource" auth="Container" type="javax.sql.DataSource"
driverClassName="org.apache.derby.jdbc.EmbeddedDriver" url="connection.url"
username="suhail" password="suhail" maxActive="20" maxIdle="10" maxWait="-1" />
and the following lines in web.xml
: 以及
web.xml
的以下几行:
<resource-ref>
<description>my connection</description>
<res-ref-name>jdbc/PollDatasource</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
What am i missing ? 我想念什么?
NOTE : I am using Netbeans 7.1 注意:我正在使用Netbeans 7.1
You have to obtain
the naming/environment context: 您必须
obtain
命名/环境上下文:
Context initContext = new InitialContext();
Context envContext = (Context)initContext.lookup("java:comp/env");
DataSource ds = (DataSource)envContext.lookup("jdbc/PollDatasource");
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