java 数据库连接（oracle)

希望大家帮帮忙哈，数据库都起来了，运行其它的java+数据库实例都是正确的，表名是：users
错误是这个：
java.sql.SQLException: ORA-00904: 无效列名 at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:111)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:330)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:287)
at oracle.jdbc.driver.T4C8Oall.receive(T4C8Oall.java:742)
at oracle.jdbc.driver.T4CPreparedStatement.doOall8(T4CPreparedStatement.java:212)
at oracle.jdbc.driver.T4CPreparedStatement.executeForDescribe(T4CPreparedStatement.java:795)
at oracle.jdbc.driver.OracleStatement.executeMaybeDescribe(OracleStatement.java:1030)
at oracle.jdbc.driver.T4CPreparedStatement.executeMaybeDescribe(T4CPreparedStatement.java:835)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1123)
at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3284)
at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:3328)
at com.lan.controller.LoginControll.doGet(LoginControll.java:37)
at com.lan.controller.LoginControll.doPost(LoginControll.java:62)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:877)
at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:594)
at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1675)
at java.lang.Thread.run(Unknown Source)相关代码是：
String id = request.getParameter("username");
String password = request.getParameter("password");
Connection ct = null;
PreparedStatement st = null;
ResultSet res = null;
try {

      //Class.forName("oracle.jdbc.driver.OracleDriver");
        Class.forName("oracle.jdbc.driver.OracleDriver");
      //ct = DriverManager.getConnection("jdbc:oracle:thin:@127.0.1.1:1521:MYORACLE","scott","lan_liang");
        ct = DriverManager.getConnection("jdbc:oracle:thin:@127.0.0.1:1521:MyOracle","scott","lan_liang");       
        //st = ct.prepareStatement("select username, userpassword from users where id=? and password=?");
        st = ct.prepareStatement("select username, userpassword from users where id=? and password=?");
        st.setObject(1, id);
      st.setObject(2, password);
      res = st.executeQuery();
      
if (res.next()) { //res.next()方法判断是否还有下一条记录
request.getRequestDispatcher("/Mainview").forward(request, response);
}else{
request.getRequestDispatcher("/Login").forward(request, response);
}
} catch (Exception e) {
e.printStackTrace();
}finally
{
try {
res.close();
st.close();
ct.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}