开发运行环境：OEPE 12c（12.1.1.1.0）+ WebLogic Server 12c（12.1.1.1.0）+ Oracle Database 10g Express Edition 10.2.0.1
JPA Entity创建好了，谁来使用这些对象呢？答案是Data Access Objects（DAO）。
DAO负责对Entity的增加、修改、删除、查询。
JPA Entity创建好了，谁来使用这些对象呢？答案是Data Access Objects（DAO）。
DAO负责对Entity的增加、修改、删除、查询。
1. LoginJPADao.java
package com.oracle.ticketsystem.dao.impl;
import com.oracle.ticketsystem.beans.Technician;
import com.oracle.ticketsystem.dao.ILoginDao;
public class LoginJPADao extends BaseJPADao implements ILoginDao {
public LoginJPADao() {
// TODO Auto-generated constructor stub
}
@Override
public Technician login(String id, String pwd) {
Technician technician = getEntityManager().find(Technician.class, id);
if (technician == null) {
return null;
}
if (technician.getPassword().equals(pwd)) {
return technician;
}
return null;
}
}
2. ProductJPADao.java
/**
*
*/
package com.oracle.ticketsystem.dao.impl;
import java.util.List;
import javax.persistence.Query;
import com.oracle.ticketsystem.beans.Product;
import com.oracle.ticketsystem.dao.IProductDao;
/**
* The JPA DAO implementation for Product entity.
*
*/
public class ProductJPADao extends BaseJPADao implements IProductDao {
/**
* Default no-arg constructor
*/
public ProductJPADao() {
super();
}
/*
* (non-Javadoc)
*
* @see com.oracle.ticketsystem.dao.IProductDAO#getAllProducts()
*/
@SuppressWarnings("unchecked")
@Override
public List getAllProducts() {
Query allProductsQuery = getEntityManager().createQuery(
"select p from Product p");
List allProducts = allProductsQuery.getResultList();
return allProducts;
}
/*
* (non-Javadoc)
*
* @see com.oracle.ticketsystem.dao.IProductDAO#getProduct(int)
*/
@Override
public Product getProduct(long id) {
return getEntityManager().find(Product.class, id);
}
}
3. TicketJPADao.java
package com.oracle.ticketsystem.dao.impl;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import javax.persistence.EntityTransaction;
import javax.persistence.Query;
import com.oracle.ticketsystem.beans.Product;
import com.oracle.ticketsystem.beans.Technician;
import com.oracle.ticketsystem.beans.Ticket;
import com.oracle.ticketsystem.beans.TicketHistory;
import com.oracle.ticketsystem.dao.ITicketDao;
public class TicketJPADao extends BaseJPADao implements ITicketDao {
/**
* Date pattern used across the application.
*/
public static final String DATE_PATTERN = "MM/dd/yyyy hh:mm:ss aa"; //$NON-NLS-1$
/**
* Default no-arg constructor
*/
public TicketJPADao() {
}
@Override
public Ticket add(long productId, String customerName,
String customerEmail, String title, String description) {
Product product = getEntityManager().find(Product.class, productId);
if (product == null) {
throw new RuntimeException("While adding a new ticket, "
+ "could not find reference to the given product Id: "
+ productId);
}
Ticket ticket = new Ticket();
ticket.setProduct(product);
ticket.setCustomerName(customerName);
ticket.setCustomerEmail(customerEmail);
ticket.setTitle(title);
ticket.setDescription(description);
ticket.setState("NEW"); // always NEW state
SimpleDateFormat dtFormat = new SimpleDateFormat(DATE_PATTERN);
ticket.setSubmissionDate(dtFormat.format(new Date()));
Long maxId = getMaxId("SELECT max(t.id) FROM Ticket t");
// setting the ticket Id
ticket.setId((maxId == null) ? 0 : maxId + 1);
EntityTransaction t = getEntityManager().getTransaction();
t.begin();
getEntityManager().persist(ticket);
t.commit();
return ticket;
}
@Override
public Ticket get(long ticketId) {
return getEntityManager().find(Ticket.class, ticketId);
}
@SuppressWarnings("unchecked")
@Override
public List getTicketsOwnedByTechnician(String technicianId) {
Query query = getEntityManager().createQuery(
"SELECT t from Ticket t WHERE t.technician.id = :technicianId");
query.setParameter("technicianId", technicianId);
return query.getResultList();
}
@Override
public Ticket update(long ticketId, String technicianId, String comment,
String state) {
EntityTransaction t = getEntityManager().getTransaction();
t.begin();
Ticket ticket = get(ticketId);
if (ticket == null) {
return null;
}
ticket.setState(state);
Technician technician = null;
if (technicianId != null) {
technician = getEntityManager()
.find(Technician.class, technicianId);
if (technician == null) {
throw new RuntimeException("No technician found for the ID '"
+ technicianId + "'");
}
}
ticket.setTechnician(technician);
TicketHistory ticketHistory = new TicketHistory();
Long maxTicketHistoryId = getMaxId("SELECT max(h.id) FROM TicketHistory h");
// setting the ticketHistory Id
ticketHistory.setId((maxTicketHistoryId == null) ? 0
: maxTicketHistoryId + 1);
if (technician != null) {
ticketHistory.setTechnician(technician);
}
ticketHistory.setState(state);
ticketHistory.setComments(comment);
ticketHistory.setTicket(ticket);
SimpleDateFormat dtFormat = new SimpleDateFormat(DATE_PATTERN);
ticketHistory.setUpdateDate(dtFormat.format(new Date()));
getEntityManager().persist(ticketHistory);
ticket.getTicketHistory().add(ticketHistory);
t.commit();
return ticket;
}
@SuppressWarnings("unchecked")
@Override
public List getOpenTickets() {
Query openTicketsQuery = getEntityManager().createQuery(
"SELECT t FROM Ticket t " + "WHERE t.state = :newState "
+ "OR t.state = :openState");
openTicketsQuery.setParameter("newState", "NEW");
openTicketsQuery.setParameter("openState", "OPEN");
return openTicketsQuery.getResultList();
}
@Override
public void remove(long ticketId) {
Ticket ticket = get(ticketId);
if (ticket != null) {
EntityTransaction trx = getEntityManager().getTransaction();
trx.begin();
for (TicketHistory ticketHistory : ticket.getTicketHistory()) {
getEntityManager().remove(ticketHistory);
}
ticket.getTicketHistory().clear();
getEntityManager().remove(ticket);
trx.commit();
}
}
private long getMaxId(String maxQuery) {
Query maxIdQuery = getEntityManager().createQuery(maxQuery);
Long maxId = 1L;
if ((maxIdQuery.getResultList() != null)
&& (maxIdQuery.getResultList().size() > 0)) {
maxId = (Long) maxIdQuery.getResultList().get(0);
}
return maxId;
}
}
4.
JPADaoFactory .java
/**
*
*/
package com.oracle.ticketsystem.dao.impl;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
/**
* A JPA DAO factory for providing reference to EntityManager.
*
*/
public class JPADaoFactory {
private static final String PERSISTENCE_UNIT_NAME = "TroubleTicketSystemServer";
private static EntityManagerFactory entityManagerFactory;
private static EntityManager entityManager;
/**
* Returns reference to EntityManager instance. If null then create it using
* the persistence unit name as defined in the persistence.xml
*
* @return EntityManager
*/
public static EntityManager createEntityManager() {
if (entityManager == null) {
entityManagerFactory = Persistence
.createEntityManagerFactory(PERSISTENCE_UNIT_NAME);
entityManager = entityManagerFactory.createEntityManager();
}
return entityManager;
}
public static void close() {
entityManager.close();
entityManagerFactory.close();
}
}
5.
BaseJPADao .java
package com.oracle.ticketsystem.dao.impl;
import javax.persistence.EntityManager;
public class BaseJPADao {
/**
* Default no-arg constructor
*/
public BaseJPADao() {
}
/**
* Returns JPA EntityManager reference.
*
* @return
*/
public EntityManager getEntityManager() {
return JPADaoFactory.createEntityManager();
}
}
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