Problem retrieving data from relational databse using persistence

Hi. I'm newbie here and also in jsf.

Recently, I have problem with my login page. I have database with table customer. What I want to do is when user enter username and password, it will go to another page. But, the problem is how to retrieve data from database. I have created persistence, but I still cant find the way how to retrieve data from database. Can someone help me? I'm using netbean for jsf.

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package entity;

import java.io.Serializable;
import javax.persistence.*;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
import javax.xml.bind.annotation.XmlRootElement;

/**
 *
 * @author Anon
 */

@Entity
@Table(name = "CUSTOMER")
@XmlRootElement
@NamedQueries({
    @NamedQuery(name = "Customer.findAll", query = "SELECT c FROM Customer c"),
    @NamedQuery(name = "Customer.findByCustomerId", query = "SELECT c FROM Customer c WHERE c.customerId = :customerId"),
    @NamedQuery(name = "Customer.findByName", query = "SELECT c FROM Customer c WHERE c.name = :name"),
    @NamedQuery(name = "Customer.findByAddressline1", query = "SELECT c FROM Customer c WHERE c.addressline1 = :addressline1"),
    @NamedQuery(name = "Customer.findByAddressline2", query = "SELECT c FROM Customer c WHERE c.addressline2 = :addressline2"),
    @NamedQuery(name = "Customer.findByCity", query = "SELECT c FROM Customer c WHERE c.city = :city"),
    @NamedQuery(name = "Customer.findByState", query = "SELECT c FROM Customer c WHERE c.state = :state"),
    @NamedQuery(name = "Customer.findByPhone", query = "SELECT c FROM Customer c WHERE c.phone = :phone"),
    @NamedQuery(name = "Customer.findByFax", query = "SELECT c FROM Customer c WHERE c.fax = :fax"),
    @NamedQuery(name = "Customer.findByEmail", query = "SELECT c FROM Customer c WHERE c.email = :email"),
    @NamedQuery(name = "Customer.findByCreditLimit", query = "SELECT c FROM Customer c WHERE c.creditLimit = :creditLimit"),
    @NamedQuery(name = "Customer.findByPassword", query = "SELECT c FROM Customer c WHERE c.password = :password")})
public class Customer implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @Basic(optional = false)
    @NotNull
    @Column(name = "CUSTOMER_ID")
    private Integer customerId;
    @Size(max = 30)
    @Column(name = "NAME")
    private String name;
    @Size(max = 30)
    @Column(name = "ADDRESSLINE1")
    private String addressline1;
    @Size(max = 30)
    @Column(name = "ADDRESSLINE2")
    private String addressline2;
    @Size(max = 25)
    @Column(name = "CITY")
    private String city;
    @Size(max = 2)
    @Column(name = "STATE")
    private String state;
    // @Pattern(regexp="^\$?(\\d{3})\$?[- ]?(\\d{3})[- ]?(\\d{4})$", message="Invalid phone/fax format, should be as xxx-xxx-xxxx")//if the field contains phone or fax number consider using this annotation to enforce field validation
    @Size(max = 12)
    @Column(name = "PHONE")
    private String phone;
    // @Pattern(regexp="^\$?(\\d{3})\$?[- ]?(\\d{3})[- ]?(\\d{4})$", message="Invalid phone/fax format, should be as xxx-xxx-xxxx")//if the field contains phone or fax number consider using this annotation to enforce field validation
    @Size(max = 12)
    @Column(name = "FAX")
    private String fax;
    // @Pattern(regexp="[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?", message="Invalid email")//if the field contains email address consider using this annotation to enforce field validation
    @Size(max = 40)
    @Column(name = "EMAIL")
    private String email;
    @Column(name = "CREDIT_LIMIT")
    private Integer creditLimit;
    @Column(name = "PASSWORD")
    private Integer password;
    @JoinColumn(name = "ZIP", referencedColumnName = "ZIP_CODE")
    @ManyToOne(optional = false)
    private MicroMarket zip;
    @JoinColumn(name = "DISCOUNT_CODE", referencedColumnName = "DISCOUNT_CODE")
    @ManyToOne(optional = false)
    private DiscountCode discountCode;

public Customer() {
    }

public Customer(Integer customerId) {
        this.customerId = customerId;
    }

public Integer getCustomerId() {
        return customerId;
    }

public void setCustomerId(Integer customerId) {
        this.customerId = customerId;
    }

public String getName() {
        return name;
    }

public void setName(String name) {
        this.name = name;
    }

public String getAddressline1() {
        return addressline1;
    }

public void setAddressline1(String addressline1) {
        this.addressline1 = addressline1;
    }

public String getAddressline2() {
        return addressline2;
    }

public void setAddressline2(String addressline2) {
        this.addressline2 = addressline2;
    }

public String getCity() {
        return city;
    }

public void setCity(String city) {
        this.city = city;
    }

public String getState() {
        return state;
    }

public void setState(String state) {
        this.state = state;
    }

public String getPhone() {
        return phone;
    }

public void setPhone(String phone) {
        this.phone = phone;
    }

public String getFax() {
        return fax;
    }

public void setFax(String fax) {
        this.fax = fax;
    }

public String getEmail() {
        return email;
    }

public void setEmail(String email) {
        this.email = email;
    }

public Integer getCreditLimit() {
        return creditLimit;
    }

public void setCreditLimit(Integer creditLimit) {
        this.creditLimit = creditLimit;
    }

public Integer getPassword() {
        return password;
    }

public void setPassword(Integer password) {
        this.password = password;
    }

public MicroMarket getZip() {
        return zip;
    }

public void setZip(MicroMarket zip) {
        this.zip = zip;
    }

public DiscountCode getDiscountCode() {
        return discountCode;
    }

public void setDiscountCode(DiscountCode discountCode) {
        this.discountCode = discountCode;
    }

@Override
    public int hashCode() {
        int hash = 0;
        hash += (customerId != null ? customerId.hashCode() : 0);
        return hash;
    }

@Override
    public boolean equals(Object object) {
        // TODO: Warning - this method won't work in the case the id fields are not set
        if (!(object instanceof Customer)) {
            return false;
        }
        Customer other = (Customer) object;
        if ((this.customerId == null && other.customerId != null) || (this.customerId != null && !this.customerId.equals(other.customerId))) {
            return false;
        }
        return true;
    }

@Override
    public String toString() {
        return "entity.Customer[ customerId=" + customerId + " ]";
    }
    
}

This is the code generated by netbean when I choose "Entity Classes From Databse".

Just say I want to retrieve only one customer name. Can I simply write <h

utputText value="#{Customer.name}"> like this?

We don't have many rules here at the JavaRanch, but we do insist that you use your Real Name and not some sort of "handle" or obvious alias. If you're not sure about this, see
http://www.javaranch.com/name.jsp .

after you create your entity classes eg Customer.java, you need to create session beans for the entity classes in another package say session classes. they have your entity class name and Facade suffix eg CustomerFacade.java

then in your servlet you reference the session beans with the annotation eg

@EJB
CustomerFacade customerFacade;

then in the method where you want to get the username and password you can use JPQL which is a query language for JPA this is where i am stuck too