AJUDA, PLEASE! Não consigo enviar o parametro de JSF para Bean.java

public class AgendaBean {
    private String cod;
    private Connection conn;
    public void abrirConexao()
            throws SQLException,
            NamingException,
            ClassNotFoundException
    {
        if (conn != null) return;
        Class.forName("org.gjt.mm.mysql.Driver");
        conn = DriverManager.getConnection("jdbc:mysql://localhost/bdlivros2","root","senha123");
    }
 
    public Result getLista()
            throws SQLException,
            NamingException,
            ClassNotFoundException
    {
        try{
            abrirConexao();
            Statement stmt = conn.createStatement();
            ResultSet result = stmt.executeQuery("SELECT * from livros");
            return ResultSupport.toResult(result);
        }finally{
            fecharConexao();
        }
    }
    public String exclui() throws SQLException, NamingException, ClassNotFoundException {   
        String result = "erro";  
        try {   
            abrirConexao();
            Statement stmt = conn.createStatement();   
            stmt.executeUpdate("delete from livros where cod = '" + cod + "'");   
            stmt.close();   
            result = "ok";   
        } catch (SQLException e) {   
            System.err.println ("Erro: "+e);   
            result = "erro";   
        }   
        return result;   
    }

<h:commandLink value="Excluir" action="#{agenda.exclui}" >
           <f:setPropertyActionListener value="#{dados.cod}" target="#{agenda.cod}"  /> 
</h:commandLink>

<managed-bean>
        <managed-bean-name>agenda</managed-bean-name>
        <managed-bean-class>br.com.integrator.cap15.jsf.AgendaBean</managed-bean-class>
        <managed-bean-scope>session</managed-bean-scope>
    </managed-bean>
</faces-config>