菜鸟哭了,数据库链接问题

Question

能过servlet来登陆ACCESS数据库,请大家帮我看一看为什么登陆不了,总是出错:
这个是servlet:
 public void doPost(HttpServletRequest request, HttpServletResponse response) throws
            ServletException, IOException {
        response.setContentType(CONTENT_TYPE);
        PrintWriter out = response.getWriter();
        System.out.println("hello");
        request.setCharacterEncoding("GBK");
        String action = request.getParameter("action");
        if (action.equals("login")) {
            String user = request.getParameter("username");
            String psw = request.getParameter("psw");
            LoginBean lb = new LoginBean();
            boolean hasUser = lb.validate(user,psw);
            System.out.print(hasUser);
            if (hasUser) {
            RequestDispatcher rd = request.getRequestDispatcher("/main.jsp");
            rd.forward(request, response);
            }else{
            RequestDispatcher rd = request.getRequestDispatcher("/error.jsp");
            rd.forward(request, response);
            }        }
    }
这个是实现类:package mybage;
import db.DataBaseConnection;
import java.sql.*;
public class LoginBean {
    boolean hasUser;
    private Connection connection;
    public LoginBean(){
        this.connection = DataBaseConnection.getConnection();
    }  
    public boolean validate(String user,String psw ) {
       hasUser = false;
       System.out.println(user + psw);
       if ((user != "") && (psw != "")) {
           try {
              Statement stmt = connection.createStatement();
              String sql ="select USER_PASS from WL_MEMBER_INFO where USER_NAME='"+user+"'";
              ResultSet rs = stmt.executeQuery(sql);
              if (rs.next() && rs.getString("USER_PASS").equals(psw)) {
                  hasUser=true;
              }
          } catch (Exception ex) {
              ex.printStackTrace();
              hasUser = false;
          }
       }
      return hasUser;
    }
}
为什么程序一走到这里就出错:Statement stmt = connection.createStatement();?????

Answer 1

这个是DataBaseConnection类:
package db;
import java.sql.*;public class DataBaseConnection {
    public static Connection getConnection(){
        Connection connection = null;
        String driver = "sun.jdbc.odbc.JdbcOdbcDriver";
        String url = "jdbc:odbc:yaoutest";
        String username = "";
        String password = "";
        try {
            Class.forName(driver);
            Connection conn = DriverManager.getConnection(url,username,password);
        } catch (Exception ex) {
          ex.printStackTrace();
        }
        return connection;
    }
}

Answer 2

嘻嘻,,,,,问题解决了.是自己太马虎了.呵呵.......不过CSDN里现在怎么了,不像以前有人气了.