请各位高手帮忙看看这段servlet连接数据库的程序,急!!!!!

Question

报出的信息在这里，可是我看不懂啊！！HTTP Status 500 - --------------------------------------------------------------------------------type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception java.lang.NullPointerException
at sic.check.doGet(check.java:34)
at sic.check.doPost(check.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:247)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:256)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2422)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:171)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:163)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:199)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:828)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:700)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:584)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
at java.lang.Thread.run(Thread.java:534)--------------------------------------------------------------------------------Apache Tomcat/4.1.30

Answer 1

String Number = request.getParameter("number");
          String Name = request.getParameter("name");
          String Lqcc=request.getParameter("lqcc");
          boolean flag = false;
          session.setAttribute("Xm",Name);
          session.setAttribute("Number",Number);
//-------------------------------------------------------------------------
这里有错误，好好检查检查！可能没有值传过来，之后拿这个 ""做运算，可能出错了。

Answer 2

但是它连Acces数据库是没问题的啊！那个数据库没有密码，而这个加设了密码，是不是有个原因呢？

Answer 3

是不是odbc数据源的问题？
  换了数据库的话，要重新设置odbc的

Answer 4

你的库就没有public class Db
{
   String sDBDriver="com.microsoft.jdbc.sqlserver.SQLServerDriver";
   String sConnStr="jdbc:microsoft:sqlserver://192.168.1.33:1433;SelectMethod=Cursor";
   Connection connect=null;
   ResultSet rs=null;
    String user="sa";
    String password="sa";    public Db() {
        try{
            Class.forName(sDBDriver);
            connect = DriverManager.getConnection(sConnStr,user,password);
            connect.setCatalog("device");
        }
        catch(Exception e){
            System.out.println(e.getMessage());
        }
    }    public ResultSet executeQuery(String sql){
        try{
            Statement stmt=connect.createStatement();
            rs=stmt.executeQuery(sql);
        }
        catch(SQLException ex){
            System.err.println(ex.getMessage());
        }
        return rs;
    }
}连上，改动如下：