Email duplicado no struts

[ju1]

Olá pessoal,
como faço para verificar no banco de dados
se existe um email duplicado?

Se alguém puder me dar uma dica de como fazer isso
agradeço muito.

Segue o meu bean:

package cadastro.bean;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.LinkedList;

import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.DataSource;

import cadastro.bean.UserData;

public class AdminUsers {

protected static DataSource dataSource;

public AdminUsers() throws Exception {
    if (dataSource == null) {
        try {
            InitialContext ic = new InitialContext();
            // se for tomcat
            dataSource = (DataSource) ic.lookup("java:comp/env/jdbc/cadastroDS");
            // no JBoss faça
            // dataSource = (DataSource) ic.lookup("java:jdbc/cadastroDS");

        } catch (NamingException ex) {
            System.out.println(ex.getMessage());
            throw ex;
        }
    }
}

protected Connection getConnection() throws SQLException {
    Connection conn = null;
    try {
        conn = dataSource.getConnection();
    }
    catch (SQLException e) {
        throw e;
    }
    return conn;
}


protected void closeConnection(
    Connection conn,
    PreparedStatement stmt,
    ResultSet rs) {
    if (rs != null) {
        try {
            rs.close();
        } catch (SQLException e) {
        }
    }
    if (stmt != null) {
        try {
            stmt.close();
        } catch (SQLException e) {
        }
    }
    if (conn != null) {
        try {
            conn.close();
        } catch (SQLException e) {
        }
    }
}

public LinkedList getUserList() throws SQLException {
    Connection conn = null;
    PreparedStatement stmt = null;
    ResultSet rs = null;
    LinkedList users  = new LinkedList();
    try {
        conn = getConnection();
        stmt = conn.prepareStatement("select * from dbcadastro");
        rs = stmt.executeQuery();
        while (rs.next()) {
            UserData user = new UserData();
          //  user.setId(rs.getInt("id"));
            user.setNome(rs.getString("nome"));
            user.setSobrenome(rs.getString("sobrenome"));
            user.setOpcaoemail(rs.getString("mostraremail"));
            user.setEmail(rs.getString("email"));
            user.setTelefone(rs.getString("telefone"));
            user.setEndereco(rs.getString("endereco"));
            user.setBairro(rs.getString("bairro"));
            user.setCidade(rs.getString("cidade"));
            user.setEstado(rs.getString("estado"));
            user.setLogin(rs.getString("login"));
            user.setSenha(rs.getString("senha"));
            user.setInformativos(rs.getString("informativos"));

            
            users.add(user);
        }
    }
    catch (SQLException e) {
        throw e;
    }
    finally {
        closeConnection(conn, stmt, rs);
    }
    return users;
}

public void insertUser(UserData user) throws SQLException {
    Connection conn = null;
    PreparedStatement stmt = null;
    ResultSet rs = null;
    try {
        conn = getConnection();
        stmt = conn.prepareStatement(
            "insert into dbcadastro \n" +
            "(nome, sobrenome, mostraremail, email, telefone, endereco, bairro, cidade, estado, login, senha, informativos) \n" +
            "values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)");
        stmt.setString(1, user.getNome());
        stmt.setString(2, user.getSobrenome());
        stmt.setString(3, user.getOpcaoemail());
        stmt.setString(4, user.getEmail());
        stmt.setString(5, user.getTelefone());
        stmt.setString(6, user.getEndereco());
        stmt.setString(7, user.getBairro());
        stmt.setString(8, user.getCidade());
        stmt.setString(9, user.getEstado());
        stmt.setString(10, user.getLogin());
        stmt.setString(11, user.getSenha());
        stmt.setString(12, user.getInformativos());

        
     stmt.executeUpdate();
    }
    catch (SQLException e) {
        throw e;
    }
    finally {
        if (rs != null) {
            rs.close();
        }
        if (stmt != null) {
            stmt.close();
        }
    }
}

public void updateUser(UserData user) throws SQLException {
    Connection conn = null;
    PreparedStatement stmt = null;
    ResultSet rs = null;
    try {
        conn = getConnection();
        stmt = conn.prepareStatement(
            "update dbcadastro set \n" +
            "nome = ?, sobrenome = ?, mostraremail = ?, email = ?, telefone = ?, endereco = ?, bairro = ?, cidade = ?, estado = ?, informativos = ?\n" +
            "where id = ?");
       
        stmt.setString(1, user.getNome());
        stmt.setString(2, user.getSobrenome());
        stmt.setString(3, user.getOpcaoemail());
        stmt.setString(4, user.getEmail());
        stmt.setString(5, user.getTelefone());
        stmt.setString(6, user.getEndereco());
        stmt.setString(7, user.getBairro());
        stmt.setString(8, user.getCidade());
        stmt.setString(9, user.getEstado());
        stmt.setString(10, user.getInformativos());
        stmt.setInt(11, user.getId());

       stmt.executeUpdate();
    }
    catch (SQLException e) {
        throw e;
    }
    finally {
        if (rs != null) {
            rs.close();
        }
        if (stmt != null) {
            stmt.close();
        }
    }
}

public void deleteUser(UserData user) throws SQLException {

// public void deleteUser(int id) throws SQLException {
Connection conn = null;
PreparedStatement stmt = null;
ResultSet rs = null;
try {
conn = getConnection();
stmt = conn.prepareStatement(
“delete from dbcadastro where id = ?”);
stmt.setInt(1, user.getId());
stmt.executeUpdate();
}
catch (SQLException e) {
throw e;
}
finally {
if (rs != null) {
rs.close();
}
if (stmt != null) {
stmt.close();
}
}
}
}

Segue o meu action:

package cadastro.action;

import java.sql.SQLException;
import java.util.LinkedList;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.struts.action.Action;
import org.apache.struts.action.ActionError;
import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.validator.DynaValidatorForm;

import cadastro.bean.AdminUsers;
import cadastro.bean.UserData;

public class SaveInsertUsuarioAction extends Action {

public ActionForward execute(
	ActionMapping mapping,
	ActionForm form,
	HttpServletRequest request,
	HttpServletResponse response)
	throws Exception {
		
	DynaValidatorForm dynaForm = (DynaValidatorForm) form;
	ActionErrors errors = new ActionErrors();
	String senha1 = (String)dynaForm.get("senha");
	String senha2 = (String)dynaForm.get("confirmasenha");
	
	String nome = (String)dynaForm.get("nome");
	String sobrenome = (String)dynaForm.get("sobrenome");
	String email = (String)dynaForm.get("email");
	String login = (String)dynaForm.get("login");
	String senha = (String)dynaForm.get("senha");

HttpSession session = request.getSession();

			// popula o bean do usuario com os dados que vieram do Form
			UserData user = (UserData) session.getAttribute("insertUserBean");
			//user.setIdUsuario(Integer.parseInt((String)dynaForm.get("idUsuario")));
			
			 if ((nome == null) || (nome.length() < 1)) {
        errors.add("nome", new ActionError("error.nome.required"));
        }
        
         if ((sobrenome == null) || (sobrenome.length() < 1)) {
        errors.add("sobrenome", new ActionError("error.sobrenome.required"));
          }
          
         if ((email == null) || (email.length() < 1)) {
          errors.add("email", new ActionError("error.email.required"));
          }
        
         if ((login == null) || (login.length() < 1)) {
          errors.add("login", new ActionError("error.login.required"));
          }
          
          if ((senha == null) || (senha.length() < 1)) {
          errors.add("senha", new ActionError("error.senha.required"));
          }
      

         
          if (!senha1.equals(senha2))
            {
          errors.add("confirmasenha", new ActionError("error.confirmasenha"));
            }

       
       	user.setNome((String)dynaForm.get("nome"));
			user.setSobrenome((String)dynaForm.get("sobrenome"));
			user.setOpcaoemail((String)dynaForm.get("opcaoemail"));
			user.setEmail((String)dynaForm.get("email"));
			user.setTelefone((String)dynaForm.get("telefone"));					
			user.setEndereco((String)dynaForm.get("endereco"));
			user.setBairro((String)dynaForm.get("bairro"));
			user.setCidade((String)dynaForm.get("cidade"));
			user.setEstado((String)dynaForm.get("estado"));
			user.setLogin((String)dynaForm.get("login"));
			user.setSenha((String)dynaForm.get("senha"));
        user.setInformativos((String)dynaForm.get("informativos"));						
			
			
											
		   AdminUsers adminUsers = new AdminUsers();
			
			
			
	      String email1 = EMAIL QUE VEM DO BANCO ;
			
			if(email.equals(email1))
			  {
			   
			  
			  errors.add("Email", new ActionError("error.Email.duplicateKey"));

	      }
	
		  
	
 
    if (!errors.isEmpty()) {
		   saveErrors(request, errors);
		   return (mapping.findForward("error"));
	      }

		 
		 
		   // adminUsers.insertUser(user);
		  
		  
		   return (mapping.findForward("success"));
	
   }

}

Não sei como puxar essa verificação lá do bean