Problem med at oprette forb til db
Det skal siges at det har fungeret før, men driller igen :FORBINDELSE TIL DB:
public class ConnectToDatabase
{
public static Connection con= null;
public static Statement stmt = null;
//Opret forbindelse til MySQL database i konstruktør
public ConnectToDatabase () throws Exception
{
try
{
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection("jdbc:mysql://localhost/bilreservedele","root","touel");
//con.setAutoCommit(false);
}
catch (ClassNotFoundException e)
{
e.printStackTrace();
System.out.println( e.getMessage());
}
//Check om forb er gyldig....
if (con == null)
{
System.err.println ("FEJL ! Kunne ikke oprette forbindelse");
}
}
public Connection getCon ()
{
return con;
}
public void setCon (Connection con)
{
ConnectToDatabase.con= con;
}
/** Denne metode bruges hver gang man skal læse fra databasen. */
public ResultSet ExecuteResultSet(String SqlStatement)
{
ResultSet ReturnResultSet;
try{
stmt = con.createStatement();
ReturnResultSet = stmt.executeQuery(SqlStatement);
return ReturnResultSet;
}catch (SQLException e){
System.out.println(e.getMessage());
}
return null;
}
LIDT JSP KODE:
<body>
<%
ResultSet RS = DbQuery.DbQueryBil.visMaerke();
if (RS == null) {
out.println("DEN ER TOM!!!");
}
try {
while (RS.next()) {
out.println(RS.getString("bilmaerke"));
}
} catch (Exception e) {
System.out.println(e);
}
%>
</body>
DEN KALDTE METODE FRA JSP:
public static ResultSet visMaerke ()throws Exception
{
ConnectToDatabase Condb= new ConnectToDatabase ();
return Condb.ExecuteResultSet("SELECT * FROM bilmaerke ");
}
TIL DETET FÅR JEG DENNE FEJL:
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1338)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1187)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:164)
at ConnectDb.ConnectToDatabase.<init>(ConnectToDatabase.java:19)
at DbQuery.DbQueryBil.visMaerke(DbQueryBil.java:35)
at org.apache.jsp.ProveIndsaetDataFraDb_jsp._jspService(org.apache.jsp.ProveIndsaetDataFraDb_jsp:79)
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:322)
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.coyote.http11.Http11Processor.process(Http11Processor.java:868)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:663)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
at java.lang.Thread.run(Thread.java:595)
com.mysql.jdbc.Driver
FEJL ! Kunne ikke oprette forbindelse
2005-11-21 00:44:12 org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet jsp threw exception
java.lang.NullPointerException
at ConnectDb.ConnectToDatabase.ExecuteResultSet(ConnectToDatabase.java:53)
at DbQuery.DbQueryBil.visMaerke(DbQueryBil.java:37)
at org.apache.jsp.ProveIndsaetDataFraDb_jsp._jspService(org.apache.jsp.ProveIndsaetDataFraDb_jsp:79)
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:322)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java%3
