Question

My Login Form is not working ,Can any please help me…

public class LoginServlet extends HttpServlet {

@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    String userName=request.getParameter("userName");
    String password=request.getParameter("password");
     DataPersistor d=new DataPersistor();
    try {
        if( d.isValidateUser(userName, password)){
               HttpSession session=request.getSession();
         session.setAttribute("name", userName);
         response.sendRedirect("index.jsp");
        }



         else{
             response.sendRedirect("login.jsp");

         }
    } catch (SQLException ex) {
        Logger.getLogger(LoginServlet.class.getName()).log(Level.SEVERE, null, ex);
    }


    } 




}

---

This is My Data Persistor Class.I am getting the Value From the Database ,

public class DataPersistor {
    Connection con;

public DataPersistor() {
    con = DBConnector.getConnection();
}

public void registerUser(User user) {
    try {
        Statement stmt = con.createStatement();
        String query = "INSERT INTO user VALUES ('" + user.getUserName() + "','" + user.getPassword() + "','" + user.getEmail() + "','" + user.getLastName() + "','" + user.getFirstName() + "','false')";
        stmt.execute(query);



    } catch (SQLException ex) {
        Logger.getLogger(DataPersistor.class.getName()).log(Level.SEVERE, null, ex);
    }





}
public boolean isValidateUser(String username,String password) throws SQLException{
    boolean result=false;
    PreparedStatement ps;
     Statement stmt = con.createStatement();
        String query = "SELECT * FROM  user WHERE username='" + username + "' and password='"+password+"'";
        ps=con.prepareStatement(query);
        ps.setString(1,username);
        ps.setString(2, password);

        ResultSet rs=ps.executeQuery();

        if(rs.next()==true){

            result=true;
        }
        return result;





}

}

---

after Clean and Build

Jul 29, 2012 8:51:46 PM com.asiahospital.servlet.LoginServlet doPost
SEVERE: null
java.sql.SQLException: Parameter index out of range (1 > number of parameters, which is 0).
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1073)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:987)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:982)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:927)
    at com.mysql.jdbc.PreparedStatement.checkBounds(PreparedStatement.java:3729)
    at com.mysql.jdbc.PreparedStatement.setInternal(PreparedStatement.java:3713)
    at com.mysql.jdbc.PreparedStatement.setString(PreparedStatement.java:4553)
    at com.asiahospital.db.DataPersistor.isValidateUser(DataPersistor.java:50)
    at com.asiahospital.servlet.LoginServlet.doPost(LoginServlet.java:32)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    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:225)
    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:98)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:999)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:565)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:309)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:619)`enter code here`

Answer 1

It looks like your connection has not been initialised properly.

Statement stmt = con.createStatement();

Check what is returned from

DBConnector.getConnection()

From your updated post(!), the problem is that your prepared statement doesnt contain any ‘?’ placeholder characters.

public boolean isValidateUser(String username, String password) throws SQLException {
    boolean result = false;

    String query = "SELECT * FROM  user WHERE username='?' and password='?'";
    PreparedStatement ps = con.prepareStatement(query);
    ps.setString(1, username);
    ps.setString(2, password);

    ResultSet rs = ps.executeQuery();

    if (rs.next() == true) {
       result = true;
    }

    return result;
}