/**
 * @see HttpServlet#HttpServlet()
 */
public Loginaction() {
    super();
    // TODO Auto-generated constructor stub
}

/**
 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
 */
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request,response);
}

/**
 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
 */
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    HttpSession session = request.getSession(true);
    String username = request.getParameter("nom");
     String password = request.getParameter("pass");
     UserDAO user = new UserDAO();
     boolean result = user.authentification(username, password);
     BaseUser user1 = user.getusername(username);
             if(result == true){
        session.setAttribute("user", user1);
         request.getRequestDispatcher("Liste_Projets.jsp").forward(request, response);
     }else{
         request.getRequestDispatcher("wrong_list.jsp").forward(request, response);
     }
}

public class UserDAO extends BaseUser{
    public boolean authentification(String login, String mdp){
        BaseUser user = getusername(login);
        if(user!=null){
             if(user.getLogin().equals(login) && user.getPassword().equals(mdp))
             return true;
             else
             return false;
        }
    }
    public BaseUser getusername(String login) {
        Session session = HibernateUtil.currentSession();
        Transaction tx = null;
        BaseUser user = null;
        try {
             tx = session.getTransaction();
             tx.begin();
             Query query = session.createQuery("from User where LOGIN='"+login+"'");
             user = (BaseUser)query.uniqueResult();
             tx.commit();
        } catch (Exception e) {
             if (tx != null) {
                 tx.rollback();
             }
             e.printStackTrace();
        } finally {
             HibernateUtil.closeSession();
     }
 return user;
}

package suivi.base;

import java.io.Serializable;

/*
 * @hibernate.class
 *  table="User"
 */
public abstract class BaseUser  implements Serializable {

    private int hashCode = Integer.MIN_VALUE;

// primary key
private java.lang.String _login;

// fields
private java.lang.String _nomPrenom;
private java.lang.String _password;
private java.lang.String _login;


// constructors
public BaseUser () {
    initialize();
}

/**
 * Constructor for primary key
 */
public BaseUser (java.lang.String _login) {
    this.setLogin(_login);
    initialize();
}

/**


protected void initialize () {}
/**
 * Return the unique identifier of this class
 * @hibernate.id
 *  generator-class="vm"
 *  column="LOGIN"
 */
public java.lang.String getLogin () {
    return _login;
}

/**
 * Set the unique identifier of this class
 * @param _login the new ID
 */
public void setLogin (java.lang.String _login) {
    this._login = _login;
    this.hashCode = Integer.MIN_VALUE;
}


/**
 * Return the value associated with the column: NOM_PRENOM
 */
public java.lang.String getNomPrenom () {
    return _nomPrenom;
}

/**
 * Set the value related to the column: NOM_PRENOM
 * @param _nomPrenom the NOM_PRENOM value
 */
public void setNomPrenom (java.lang.String _nomPrenom) {
    this._nomPrenom = _nomPrenom;
}


/**
 * Return the value associated with the column: PASSWORD
 */
public java.lang.String getPassword () {
    return _password;
}

/**
 * Set the value related to the column: PASSWORD
 * @param _password the PASSWORD value
 */
public void setPassword (java.lang.String _password) {
    this._password = _password;
}


public String toString () {
    return super.toString();
}

<script type="text/javascript">
  function Annuler(){
document.login.reset();
  }
 function valider()
 {
var ok = true;
 if (document.getElementById("nom").value.length<1)
{
ok = false;
document.getElementById("erreurLogin").innerHTML="*Obligatoire";
 }

 var x = document.getElementById("pass").value;
if(x == "")
{
    ok = false;
    document.getElementById("erreurLogin1").innerHTML="*Obligatoire";
    }
     if(ok)
   {

 document.login.submit()

   }

  }
 </script>
      ...//code
 <body>
   <form name="login"  method="Post" action="Loginaction">
                        <tr height="40px" valign="bottom">
                            <td width="150px"> </td>
                            <td     class="StyleLabel">Identifiant: </td>
                            <td width="1px"></td>
                            <td colspan="2" ><input class="input" type="text" size="24" maxlength="20" name="nom" id="nom"></td>
                            <td><label class="asterix" id="erreurLogin"></label></td>
                        </tr>

                        <tr height="40px" valign="bottom">
                        <td width="150px"></td>
                            <td  width="100px" class="StyleLabel" >Mot de passe: </td>
                    <td width="1px"></td>
                            <td colspan="2" > <input  class="input" type="password" size="24" autocomplete="off" maxlength="20" name="pass" id="pass"> </td>
                        <td ><label class="asterix" id="erreurLogin1"></label></td>
                        </tr>

                        <tr height="40px" >
                            <td> </td>
                            <td  colspan="3" align="center">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<img src="images/btnValid.gif" name="valid" value="valid" type="submit" onclick="valider();"/></td>
                        <td colspan="3" align="center">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<img src="images/btnAnnul.gif"  onclick="Annuler();"/></td>
                        </tr>
                    </table>

public boolean authentification(String login, String mdp){
    BaseUser user = getusername(login);
    if(user!=null )
     {
        if(user.getLogin().equals(login) && user.getPassword().equals(mdp))
         return true;
        else
         return false;
    }
}