Middleware
Application Server
Version: 8/31/06 GlassFish: Version 2, Build 15
This tutorial will walk you through the basic steps of developing, packaging, and deploying a Web application using the EJB 3.0 Java Persistence API (JPA).
In this application, a Java Server Faces (JSF) presentation layer will make use of JPA for persistence outside of an EJB 3.0 container.
Figure 1-1 shows the object model that this tutorial uses.
For more information on JPA, see:
JSR-220 Enterprise JavaBeans v3.0 Java Persistence API specification
Source Code:
Example Source Code (
order-jsf-jpa-example.zip
) - this is a completed version of the tutorial that you can build and deploy immediately.
Tutorial Source Code (
order-jsf-jpa-tutorial.zip
) - this is the starting point for the tutorial. By the end of the tutorial, you will make this code match the example source code.
Relational Database:
You can use any modern, relational database. This tutorial assumes that you are using Oracle Database XE:
Use the JDBC driver recommended for your database.
For Oracle Database XE, JDBC drivers are located in
<ORACLE_HOME>\jdbc\lib.
|
Note: For an Oracle database, you may also need<ORACLE_HOME>\lib\dms.jar.
|
Web Container:
You can use any Web container. This tutorial assumes that you are using one of the following Web containers:
This downloads a TopLink JPA installer JAR file like
glassfish-persistence-installer-X.X-bXX.jar.
Before starting this tutorial, you must setup and configure the required software:
Install the example and tutorial source files:
Create a directory in which to unzip the example source files.
This is the
<EXAMPLE_HOME> directory.
Unzip the
order-jsf-jpa-example.zip file to the
<EXAMPLE_HOME> directory.
This directory contains the completed tutorial source.
Create a directory in which to unzip the tutorial source files.
This is the
<TUTORIAL_HOME> directory.
Unzip the
order-jsf-jpa-tutorial.zip file to the
<TUTORIAL_HOME> directory.
This directory contains the stubbed tutorial source that you will complete in this tutorial.
For more information about the structure and content of the
<EXAMPLE_HOME> and
<TUTORIAL_HOME> directories, see
Understanding the Tutorial Source Files.
Install and setup your relational database:
Add your relational database JDBC driver to:
<EXAMPLE_HOME>\lib
<TUTORIAL_HOME>\lib
Install and setup your Web container:
Installing and Setting Up OC4J
|
Note: Before starting OC4J, remove the<ORACLE_HOME>/j2ee/home/lib/persistence.jar, if present.
|
Install TopLink JPA:
Move the TopLink JPA installer JAR file to a temporary directory.
Execute the TopLink JPA installer JAR file you downloaded by entering the following on the command line (you must use JDK 1.5):
java -jar glassfish-persistence-installer-X.X-bXX.jar
Scroll down to the end of the license agreement and click Accept.
The installer un-packs the
README, license files, and the TopLink Essentials JAR files as follows:
glassfish-persistence\README glassfish-persistence\3RD-PARTY-LICENSE.txt glassfish-persistence\toplink-essentials.jar glassfish-persistence\toplink-essentials-agent.jar glassfish-persistence\CDDLv1.0.txt
Add
toplink-essentials.jar and
toplink-essentials-agent.jar to:
<EXAMPLE_HOME>\lib
<TUTORIAL_HOME>\lib
Validate your installation:
Edit the
<EXAMPLE_HOME>\persistence-unit\src\META-INF\persistence.xml file and set the following properties to match your relational database:
<property name="
toplink.jdbc.driver" value="<jdbc-driver>"/>
<property name="
toplink.jdbc.url" value="<jdbc-url>"/>
<property name="
toplink.jdbc.password" value="<jdbc-password>"/>
<property name="
toplink.jdbc.user" value="<jdbc-user>"/>
Where:
<jdbc-driver> is the name of your JDBC driver class. Example:
oracle.jdbc.OracleDriver.
<jdbc-url> is the JDBC connection URL to your database. Example:
jdbc:oracle:thin:@myhost:l521:MYSID.
<jdbc-password> is the JDBC password you use to connect to your database. Example:
tiger.
<jdbc-user> is the JDBC user name you use to connect to your databse. Example:
scott
From the command line, change directories to the
<EXAMPLE_HOME> directory and execute:
ant -f build.xml generate-tables ant -f build.xml populate-data
Confirm that
TABLE CREATE statements are visible in the log messages written to standard out.
If they are, then you are connecting to the database successfully.
If they are not, then you are not connecting to the database. In this case, confirm your
persistence.xml file settings and ensure that your database is up and running.
From the command line, change directories to the
<EXAMPLE_HOME> directory and execute:
ant -f build.xml package.webapp
Deploy the
<EXAMPLE_HOME>\web-application\deploy\jpa-example.war file. See:
Run the application. See:
Confirm that you can see the tutorial application main page as Figure 1-2 shows.
You are now ready to start the tutorial (see Tutorial Steps).
Figure 1-2 Tutorial Application Main Page
After unzipping the
order-jsf-jpa-example.zip and
order-jsf-jpa-tutorial.zip (see
Setup and Configuration), you have an
<EXAMPLE_HOME> and <TUTORIAL_HOME> directory.
These directories contain the same structure as Example 1-1 shows. Table 1-1 describes the important content of these subdirectories.
The source files in the
<EXAMPLE_HOME> are completed versions of the tutorial that you can build and deploy immediately.
The source files in the
<TUTORIAL_HOME> subdirectory are the starting point for the tutorial. By the end of the tutorial, you will make this code match the example source code.
Example 1-1 Structure of <EXAMPLE_HOME> and <TUTORIAL_HOME>
build.xml
extras/
bin/
classes/
src/oracle/toplink/jpa/example/inventory/tools/
DDLGenerator.java
Populator.java
lib/
- JSF and JSTL JARs
- JDBC driver JARs (user-supplied)
- TopLink JPA JARs (user-supplied)
persistence-unit/
classes/
deploy/
src/META-INF
persistence.xml
src/oracle/toplink/jpa/example/inventory/
model/
Inventory.java
Item.java
Order.java
nonentity/
Category.java
web-application/
classes/
deploy/
public_html/
*.jsp
css/
images/
WEB-INF/
faces-config.xml
web.xml
src/oracle/toplink/jpa/example/inventory/
services/
InventoryService.java
OrderService.java
services/impl/
JPAResourceBean.java
ManagedInventoryBean.java
ManagedOrderBean.java
ui/
InventoryManagerBean.java
Table 1-1 Important Subdirectories in <EXAMPLE_HOME> and <TUTORIAL_HOME>
| Subdirectory | Description |
|---|---|
|
|
Contains source files that are not directly executed by the tutorial application. |
|
    |
The directory in which the
|
|
    |
The
|
|
|
The
|
|
|
Contains the source files for persistent JPA entities. |
|
    |
This is a temporary directory where the persistence unit source files are built before packaging into the persistence unit archive. |
|
    |
This directory will contain the built and packaged persistence unit
|
|
    |
This directory contains the sources required for the persistence unit including the domain classes. It also contains the
|
|
|
Contains the source files that implement the services and user interface of the tutorial application that use the JPA entities. |
|
    |
This is a temporary directory where the sources are built before packaging into the deployable archive. |
|
    |
This directory will contain the built deployable Web application,
|
|
    |
Contains the presentation layer of the application including JSPs, stylesheets (
|
|
    |
This directory includes the sources for the controller layer of the application.
|
The following procedure leads you through the important steps in creating the tutorial application. At each step, you will be directed to modify the
<TUTORIAL_HOME> source files as necessary.
Annotations are a simple, expressive means of decorating Java source code with metadata that is compiled into the corresponding Java class files for interpretation at runtime by a JPA persistence provider to manage JPA behavior.
Persistent classes are decorated with JPA annotations to tell the JPA persistence provider what classes require persistence and to specify persistent class details.
In most cases, you can rely on JPA defaults. This tutorial shows the required annotations and some common optional annotations.
For more information, see the JPA Annotation Reference.
This section describes:
This section describes how to annotate the
Inventory.java file. This is a plain old Java object (POJO). It is one of the persistent entities we want to manage using JPA.
Using the editor of your choice, open the
<TUTORIAL_HOME>\persistence-unit\src\oracle\toplink\jpa\example\inventory\model\Inventory.java source file.
Designate this class as a persistent entity using the
@Entity
annotation as
Example 1-2 shows.
By default, the name of an entity is its class name.
Also by default, the entity name is the name of the entity's database table. You can use the
@Table
annotation to override this default behavior (for an example, see
Annotating the Order Entity).
An entity's table will contain all its persistent fields. JPA specifies that all the fields of an entity are persistent unless they are decorated with the
@Transient
annotation.
Designate a persistent field as the entity's primary key using the
@Id
annotation as
Example 1-3 shows.
Example 1-3 @Id in Inventory.java
@Entity
public class Inventory {
@Id
protected long id;
...
public void setItem(Item item) {
this.item = item;
this.id = item.getSKU();
}
...
}
Each entity must have a primary key.
The
Inventory class field
id is designated as the primary key. In this case, a
@GeneratedValue
annotation is not used because the
Inventory entity gets its primary key value from its
Item as the
Inventory method
setItem shows.
Specify the characteristics of the database table column that corresponds to the primary key field using the
@Column
annotation as
Example 1-4 shows.
Example 1-4 @Column in Inventory.java
@Entity
public class Inventory {
@Id
@Column(name="ITEM_SKU", insertable=false, updatable=false)
protected long id;
...
public void setItem(Item item) {
this.item = item;
this.id = item.getSKU();
}
...
}
By default, JPA specifies that for each entity, each persistent field will correspond to a column in the entity's relational database table where the column name and type correspond to the field name and type.
You can use the
@Column
annotation to override this default behavior.
In the
Inventory class, the
@Column annotation is used to fine-tune the relational database column for field
id as
Example 1-4 shows. Because the
Inventory entity gets its primary key value from its
Item as the
Inventory method
setItem shows, we must ensure that this value is never overwritten in the database. In this case, we use the
@Column annotation to configure the column as not insertable or updatable. This means the JPA persistence provider will not include this column in
SQL INSERT or
SQL UPDATE statements. Because this column contains the foreign key to the
Inventory class's
Item, we use the
@Column annotation attribute
name to specify a name for this column that we can use when we specify the join column for the
OneToOne mapping we will make to
Item (see step
5 and
6).
Specify the relationship between the
Inventory entity and the
Item entity using the
@OneToOne
annotation as
Example 1-5 shows.
Example 1-5 @OneToOne in Inventory.java
@Entity
public class Inventory {
@Id
@Column(name="ITEM_SKU", insertable=false, updatable=false)
protected long id;
@OneToOne
protected Item item;
...
public void setItem(Item item) {
this.item = item;
this.id = item.getSKU();
}
}
By default, a JPA persistence provider will automatically manage basic mappings (for most Java primitive types, wrappers of the primitive types, and enums). You can use the
@Basic
annotation to fine-tune basic mappings.
You must specify mappings for relationships. In addition to the
@OneToOne annotation, you can use the following annotations for relationship mappings:
The
Inventory class field
item is decorated with the
@OneToOne annotation to specify the relationship between
Inventory and
Item as
Example 1-5 shows.
Specify that the foreign key column that references the
Item is the
Inventory column named
ITEM_SKU using the
@JoinColumn
annotation as
Example 1-6 shows.
Example 1-6 @JoinColumn in Inventory.java
@Entity
public class Inventory {
@Id
@Column(name="ITEM_SKU", insertable=false, updatable=false)
protected long id;
@OneToOne
@JoinColumn(name="ITEM_SKU")
protected Item item;
...
public void setItem(Item item) {
this.item = item;
this.id = item.getSKU();
}
}
Specify a persistent field as the optimistic locking field using the
@Version
annotation as
Example 1-7 shows.
Example 1-7 @Version in Inventory.java
@Entity
public class Inventory {
@Id
@Column(name="ITEM_SKU", insertable=false, updatable=false)
protected long id;
@OneToOne
@JoinColumn(name="ITEM_SKU")
protected Item item;
...
@Version
protected int version;
...
public void setItem(Item item) {
this.item = item;
this.id = item.getSKU();
}
}
The
Inventory class field
version is decorated with the
@Version annotation to specify it as the optimistic locking field.
By default, a JPA persistence provider assumes that the application is responsible for data consistency.
Oracle recommends that you use the
@Version annotation to enable JPA persistence provider-managed optimistic locking by specifying the version field or property of an entity class that serves as its optimistic lock value.
Define a named query using the
@NamedQuery
annotation as
Example 1-8 shows.
Example 1-8 @NamedQuery in Inventory.java
@Entity
@NamedQuery(
name="inventoryForCategory",
query="SELECT i FROM Inventory i WHERE i.item.category = :category and i.quantity <= :maxQuantity"
)
public class Inventory {
....
}
In a JPA application, you can use an
EntityManager to create JPA query language queries dynamically at runtime or you can pre-define such queries using the
@NamedQuery
annotation and execute them by name at runtime (see
Step 4: Using JPA Queries). This is convenient for frequently used or complex queries.
If you want to define two or more named queries, you must use the
@NamedQueries
annotations as is done in
Order.java (see
Example 1-17).
You can also create native SQL queries (see
@NamedNativeQuery
and the
@NamedNativeQueries
).
Save and close the file.
This section describes how to annotate the
Item.java file. This is a plain old Java object (POJO). It is one of the persistent entities we want to manage using JPA.
Using the editor of your choice, open the
<TUTORIAL_HOME>\persistence-unit\src\oracle\toplink\jpa\example\inventory\model\Item.java source file.
Designate this class as a persistent entity using the
@Entity
annotation as
Example 1-2 shows.
Designate a persistent field as the entity's primary key using the
@Id
annotation as
Example 1-10 shows.
Example 1-10 @Id in Item.java
@Entity
public class Item {
protected long SKU;
...
@Id
@GeneratedValue
public long getSKU() {
return SKU;
}
...
}
The
Item class property
getSKU is designated as the primary key as
Example 1-10 shows. In general, you can annotate either the field (as in
Inventory.java) or the property associated with a field. The
@GeneratedValue
annotation tells the JPA persistence provider to take responsibility for sequencing: generating and managing unique identifier values for this field.
Specify a persistent field as the optimistic locking field using the
@Version
annotation as
Example 1-11 shows.
Example 1-11 @Version in Item.java
@Entity
public class Item {
protected long SKU;
...
@Id
@GeneratedValue
public long getSKU() {
return SKU;
}
...
@Version
public void setVersion(int version) {
this.version = version;
}
...
}
The
Item class property
setVersion is decorated with the
@Version annotation to specify that corresponding field
version is the optimistic locking field.
Save and close the file.
This section describes how to annotate the
Order.java file. This is a plain old Java object (POJO). It is one of the persistent entities we want to manage using JPA.
Using the editor of your choice, open the
<TUTORIAL_HOME>\persistence-unit\src\oracle\toplink\jpa\example\inventory\model\Order.java source file.
Designate this class as a persistent entity using the
@Entity
annotation as
Example 1-2 shows.
By default, the name of an entity is its class name and, also by default, the entity name is the name of the entity's database table.
For
Order entities, you cannot create a table named
ORDER because that name is a reserved word in most relational databases. In this case, we use the
@Table
annotation to override the default table name as
Example 1-13 shows.
Designate a persistent field as the entity's primary key using the
@Id
annotation as
Example 1-3 shows.
Example 1-14 @Id in Order.java
@Entity
@Table(name="ORDER_TABLE")
public class Order {
@Id
@GeneratedValue
protected long orderId;
...
}
The
Order class field
orderId is designated as the primary key. The
@GeneratedValue
annotation tells the JPA persistence provider to take responsibility for sequencing: generating and managing unique identifier values for this field.
Specify the relationship between the
Order entity and the
Item entity using the
@OneToOne
annotation as
Example 1-5 shows.
Example 1-15 @OneToOne in Order.java
@Entity
@Table(name="ORDER_TABLE")
public class Order {
@Id
@GeneratedValue
protected long orderId;
...
@OneToOne
protected Item item;
...
}
The
Order class field
item is decorated with the
@OneToOne annotation to specify the relationship between
Order and
Item as
Example 1-15 shows.
Specify a persistent field as the optimistic locking field using the
@Version
annotation as
Example 1-7 shows.
Example 1-16 @Version in Order.java
@Entity
@Table(name="ORDER_TABLE")
public class Order {
@Id
@GeneratedValue
protected long orderId;
...
@Version
protected int version;
@OneToOne
protected Item item;
...
}
The
Order class field
version is decorated with the
@Version annotation to specify it as the optimistic locking field.
By default, a JPA persistence provider assumes that the application is responsible for data consistency.
Oracle recommends that you use the
@Version annotation to enable JPA persistence provider-managed optimistic locking by specifying the version field or property of an entity class that serves as its optimistic lock value.
Define two named queries using the
@NamedQueries
annotation as
Example 1-17 shows.
Example 1-17 @NamedQueries in Order.java
@Entity
@Table(name="ORDER_TABLE")
@NamedQueries({
@NamedQuery(
name="shippedOrdersForItem",
query="SELECT o FROM Order o JOIN o.item i WHERE i.sKU = :itemId and o.arrivalDate is not null"
),
@NamedQuery(
name="pendingOrdersForItem",
query="SELECT o FROM Order o WHERE o.item.sKU = :itemId and o.arrivalDate is null"
)
})
public class Order {
...
}
If you want to define one named query, you must use the
@NamedQuery
annotation as is done in
Inventory.java (see
Example 1-8).
Save and close the file.
The entity manager is the primary JPA interface you use to perform basic persistence operations on your entities (create, read, update, and delete).
A persistence unit defines an entity manager's configuration by logically grouping details like entity manager provider, configuration properties, and persistent managed classes.
Each persistence unit must have a name. Only one persistence unit of a given name may exist in a given EJB-JAR, WAR, EAR, or application client JAR. You specify a persistence unit by name when you acquire an entity manager factory (see Acquire an Entity Manager Factory).
You define persistence units in the
persistence.xml file.
To configure the persistence unit:
Using the editor of your choice, open the
<TUTORIAL_HOME>\persistence-unit\src\META-INF\persistence.xml file.
Replace the
<!-- class list goes here --> comment with a
<class> element for each of the persistent JPA entity classes:
<class>oracle.toplink.jpa.example.inventory.model.Inventory</class> <class>oracle.toplink.jpa.example.inventory.model.Order</class> <class>oracle.toplink.jpa.example.inventory.model.Item</class>
Set the following properties to match your relational database:
<property name="
toplink.jdbc.driver" value="<jdbc-driver>"/>
<property name="
toplink.jdbc.url" value="<jdbc-url>"/>
<property name="
toplink.jdbc.password" value="<jdbc-password>"/>
<property name="
toplink.jdbc.user" value="<jdbc-user>"/>
Where:
<jdbc-driver> is the name of your JDBC driver class. Example:
oracle.jdbc.OracleDriver.
<jdbc-url> is the JDBC connection URL to your database. Example:
jdbc:oracle:thin:@myhost:l521:MYSID.
<jdbc-password> is the JDBC password you use to connect to your databse. Example:
tiger.
<jdbc-user> is the JDBC user name you use to connect to your databse. Example:
scott
Your
persistence.xml file should look like
Example 1-18.
Example 1-18 Persistence Unit in Persistence.xml
...
<persistence-unit name="default" transaction-type="RESOURCE_LOCAL">
<provider>
oracle.toplink.essentials.PersistenceProvider
</provider>
<class>oracle.toplink.jpa.example.inventory.model.Inventory</class>
<class>oracle.toplink.jpa.example.inventory.model.Order</class>
<class>oracle.toplink.jpa.example.inventory.model.Item</class>
<properties>
<property name="toplink.logging.level" value="FINE"/>
<property name="toplink.jdbc.driver" value="oracle.jdbc.OracleDriver"/> <!-- update to match database-->
<property name="toplink.jdbc.url" value="jdbc:oracle:thin:@localhost:1521:XE"/> <!-- update to match database-->
<property name="toplink.jdbc.password" value="tiger"/> <!-- update to match database-->
<property name="toplink.jdbc.user" value="scott"/> <!-- update to match database-->
</properties>
</persistence-unit>
...
The name of this persistence unit is
default.
Its
transaction-type is
RESOURCE_LOCAL, meaning that entity managers for this persistence unit do not participate in JTA transactions.
It uses provider
oracle.toplink.essentials.PersistenceProvider.
Finally, persistence unit properties are set. You can use persistence unit properties to fine-tune the underlying JPA persistence provider and to specify the connection details for the underlying relational database that this persistence unit should be associated with.
For more information, about TopLink JPA persistence provider extensions, see TopLink JPA Extension Reference.
For more information about the
persistence.xml file, see
JSR-000220 Enterprise JavaBeans v3.0 JPA specification, section 6.3.
Save and close the file.
The main resource for managing the tutorial user interface is
oracle.toplink.jpa.example.inventory.ui.InventoryManagerBean. It contains a reference to the following classes that use JPA to implement the services provided by this application:
oracle.toplink.jpa.example.inventory.services.impl.ManagedOrderBean (implements
oracle.toplink.jpa.example.inventory.services.OrderService)
oracle.toplink.jpa.example.inventory.services.impl.ManagedInventoryBean (implements
oracle.toplink.jpa.example.inventory.services.InventoryService)
These two classes show how to use JPA to:
Both the
ManagedOrderBean and
ManagedInventoryBean use an instance of helper class
oracle.toplink.jpa.example.inventory.services.impl.JPAResourceBean to acquire an instance of the entity manager factory for the persistence unit named
default that we defined in the
persistence.xml file (see
Step 2: Configuring the Persistence Unit).
Example 1-19 shows how the entity manager factory is acquired.
Example 1-19 Acquiring the Entity Manager Factory
public EntityManagerFactory getEMF (){
if (emf == null){
emf = Persistence.createEntityManagerFactory("default");
}
return emf;
}
Once acquired, the
ManagedOrderBean and
ManagedInventoryBean classes use the entity manager factory to obtain an entity manager to perform all the basic persistence operations (create, read, update, and delete).
Example 1-20 shows how the
ManagedOrderBean uses its
EntityManager to create a new
Order entity.
Example 1-21 shows how the
ManagedOrderBean uses its
EntityManager to read an existing
Order entity by primary key.
Example 1-22 shows how the
ManagedOrderBean uses its
EntityManager to update an existing
Order entity. Any changes made to the
Order entity are persisted when the local transaction is committed.
Example 1-22 Updating an Order in ManagedOrderBean
public void alterOrderQuantity(long orderId, int newQuantity){
EntityManager em = jpaResourceBean.getEMF().createEntityManager();
try{
em.getTransaction().begin();
Order order = em.find(Order.class, orderId);
order.setQuantity(newQuantity);
em.getTransaction().commit();
}finally{
em.close();
}
}
Example 1-23 shows how the
ManagedOrderBean uses its
EntityManager to delete an existing
Order entity by primary key.
Example 1-23 Deleting an Order in ManagedOrderBean
public void requestCancelOrder(long orderId){
EntityManager em = jpaResourceBean.getEMF().createEntityManager();
try{
em.getTransaction().begin();
Order order = em.find(Order.class, orderId);
em.remove(order);
em.getTransaction().commit();
}finally{
em.close();
}
}
Both the
ManagedInventoryBean and
ManagedOrderBean classes use JPA queries. This section describes:
This section describes how to code named and dynamic queries in the
ManagedInventoryBean.java file.
Using the editor of your choice, open the
<TUTORIAL_HOME>\web-application\src\oracle\toplink\jpa\example\inventory\services\impl\ManagedInventoryBean.java source file.
Use the
EntityManager method
createNamedQuery to return a
Query instance for the query named
inventoryForCategory as
Example 1-24 shows.
Example 1-24 Using a Named Query in ManagedInventoryBean
public class ManagedInventoryBean implements InventoryService{
...
public Collection<Inventory> getInventoryForCategoryMaxQuantity(String category, int quantity){
EntityManager em = jpaResourceBean.getEMF().createEntityManager();
try{
Query query = em.createNamedQuery("inventoryForCategory");
query.setParameter("category", category);
query.setParameter("maxQuantity", quantity);
return query.getResultList();
}finally{
em.close();
}
}
...
}
You created this named query in the
Inventory class (see
Example 1-8).
Use the
EntityManager method
createQuery to create a dynamic query as
Example 1-25 shows.
Example 1-25 Using a Dynamic Query in ManagedInventoryBean
public class ManagedInventoryBean implements InventoryService{
...
//Returns a list of available item categories
public Collection<Category> getCategories(){
//Create an EntityManager from the Factory stored in the JPAResourceBean
EntityManager em = jpaResourceBean.getEMF().createEntityManager();
try{
//execute a JPQL query that collects summary data and stores it in a
//non-entity class Category. This query will pass the results of the
//query into the constructor of Category and return a list of Category
//objects
Collection<Category> result = em.createQuery("Select new oracle.toplink.jpa.example.inventory.nonentity.Category(i.category) from Item i group by i.category").getResultList();
return result;
}finally{
em.close();
}
}
...
}
Note that this query builds and returns a
Collection of
Category classes that are not entity classes. It uses summary data to create this non-entity helper class.
Save and close the file.
This section describes how to code named and dynamic queries in the
ManagedOrderBean.java file.
Using the editor of your choice, open the
<TUTORIAL_HOME>\web-application\src\oracle\toplink\jpa\example\inventory\services\impl\ManagedOrderBean.java source file.
Use the
EntityManager method
createNamedQuery to return a
Query instance for the query named
inventoryForCategory as
Example 1-24 shows.
Example 1-26 Using a Named Query in ManagedOrderBean
public class ManagedOrderBean implements OrderService{
...
// Returns those orders that have a set arrival date indicating that they have shipped
public Collection<Order> getShippedOrdersForItem(long itemId){
//Create an EntityManager from the Factory stored in the JPAResourceBean
EntityManager em = jpaResourceBean.getEMF().createEntityManager();
try{
//create an instance of the NamedQuery defined in the Inventory class.
Query query = em.createNamedQuery("shippedOrdersForItem");
//setting the provided parameters on the query
query.setParameter("itemId", itemId);
//return result of query
return query.getResultList();
}finally{
em.close();
}
}
// Returns those orders that have a set arrival date indicating that they have shipped
public Collection<Order> getPendingOrdersForItem(long itemId){
EntityManager em = jpaResourceBean.getEMF().createEntityManager();
try{
Query query = em.createNamedQuery("pendingOrdersForItem");
query.setParameter("itemId", itemId);
return query.getResultList();
}finally{
em.close();
}
}
...
}
You created these named queries in the
Order class (see
Example 1-17).
Use the
EntityManager method
createQuery to create a dynamic query as
Example 1-25 shows.
Example 1-27 Using a Dynamic Query in ManagedOrderBean
public class ManagedInventoryBean implements InventoryService{
...
//Returns a list of available item categories
public Collection<Category> getCategories(){
//Create an EntityManager from the Factory stored in the JPAResourceBean
EntityManager em = jpaResourceBean.getEMF().createEntityManager();
try{
//execute a JPQL query that collects summary data and stores it in a
//non-entity class Category. This query will pass the results of the
//query into the constructor of Category and return a list of Category
//objects
Collection<Category> result = em.createQuery("Select new oracle.toplink.jpa.example.inventory.nonentity.Category(i.category) from Item i group by i.category").getResultList();
return result;
}finally{
em.close();
}
}
...
}
As
Example 1-28 shows, use the appropriate
EntityManager methods to transactionally find an
Order by primary key and remove it.
Example 1-28 Finding and Removing an Order in a Transaction in ManagedOrderBean
public class ManagedInventoryBean implements InventoryService{
...
// request that an order be canceled. Assume success if no exception is thrown
public void requestCancelOrder(long orderId){
//Create an EntityManager from the Factory stored in the JPAResourceBean
EntityManager em = jpaResourceBean.getEMF().createEntityManager();
try{
//changes will be made so begin a transaction
em.getTransaction().begin();
//find the order that will be deleted. This step ensures the order
//will be managed as the specification requires the object be
//managed before remove can be called.
Order order = em.find(Order.class, orderId);
//set the order to be delet4ed
em.remove(order);
//commit the transaction, this will cause the the delete SQL to be
//sent to the database.
em.getTransaction().commit();
}finally{
em.close();
}
}
// request that an order be canceled assume success if no exception is thrown
public void alterOrderQuantity(long orderId, int newQuantity){
EntityManager em = jpaResourceBean.getEMF().createEntityManager();
try{
em.getTransaction().begin();
//ensure that this order is a managed object.
Order order = em.find(Order.class, orderId);
//update the order object directly
order.setQuantity(newQuantity);
//commit the transaction to have the update sent to the database
em.getTransaction().commit();
}finally{
em.close();
}
}
// Create a new order request for a particular item;
public void createNewOrder(Order order){
EntityManager em = jpaResourceBean.getEMF().createEntityManager();
try{
em.getTransaction().begin();
//calling persist on the order object will mark the object as new
//within the persistence context.
em.persist(order);
//commit the transaction to have the object data inserted to the
//database
em.getTransaction().commit();
}finally{
em.close();
}
}
...
}
As
Example 1-29 shows, use
EntityManager method
find to retrieve an
Order by primary key.
Example 1-29 Finding an Order by Primary Key in ManagedOrderBean
public class ManagedInventoryBean implements InventoryService{
...
// finds a particular order by the specified order id
public Order getOrderById(long orderId){
EntityManager em = jpaResourceBean.getEMF().createEntityManager();
try{
return em.find(Order.class, orderId);
}finally{
em.close();
}
}
// finds a particular order by the specified order id
public Item getItemById(long itemId){
EntityManager em = jpaResourceBean.getEMF().createEntityManager();
try{
return em.find(Item.class, itemId);
}finally{
em.close();
}
}
...
}
Save and close the file.
This section describes how to package and deploy the tutorial application, including:
To compile and package the tutorial application, from the command line, change directories to the
<TUTORIAL_HOME> directory and execute the following:
ant -f build.xml package.webapp
This creates
<TUTORIAL_HOME>\web-application\deploy\jpa-example.war.
In this tutorial, we package the persistence unit in
WEB-INF\lib\persistence-unit.jar within the
jpa-example.war file. By confining the persistence unit to its own JAR file, you can easily re-use the persistence unit in other applications.
To deploy the tutorial application to OC4J:
Verify that the following system properties are set:
JAVA_HOME - set to your JDK 1.5 installation.
Example:
C:\Program Files\Java\jdk1.5.0_06
ORACLE_HOME - set to your OC4J installation directory
Example:
C:\OC4JHome
PATH - your path must include
%JAVA_HOME%\bin
Start OC4J from the command line:
On Windows:
cd %ORACLE_HOME% cd bin oc4j.cmd -start
On UNIX:
cd %ORACLE_HOME% cd bin oc4j.sh -start
Log into the Oracle Enterprise Manager Application Server Control console:
Start a browser and enter the following URL:
http://<hostname>:8888/em/console/ias/oc4j/administration
Where
<hostname> is the name of the computer you started OC4J on.
Select Home > Applications and click the Deploy button.
In the Archive area, click the radio button next to Archive is present on local host.
Click the
Browse button and locate the
jpa-example.war file.
Click Next.
Enter an application name without spaces. For example, "JSF-JPA-Tutorial" and then click Next.
Click Deploy.
Confirm that the application deploys successfully according to the displayed log message "Application Deployer for JSF JPA Tutorial COMPLETES".
Click Return.
Confirm that the "JSF JPA Tutorial" application is listed in the Applications tab.
To deploy the tutorial application to Tomcat:
Verify that the following system properties are set:
JAVA_HOME - set to your JDK 1.5 installation.
Example:
C:\Program Files\Java\jdk1.5.0_06
CATALINA_HOME - set to your Tomcat installation directory.
Example:
C:\apache-tomcat-5.5.17
PATH - your path must include
%JAVA_HOME%\bin
Copy the
jpa-example.war file to the Tomcat
CATALINA_HOME\webapps directory.
Start Tomcat from the command line:
On Windows:
cd %CATALINA_HOME% cd bin startup.cmd
On UNIX:
cd $CATALINA_HOME cd bin startup.sh
Confirm that the application deploys successfully by looking for the log message "deployWAR INFO: Deploying web application archive jpa-example.war" on standard out or in the
CATALINA_HOME/logs/catalina.out log file.
This section describes how to access the application after deployment:
Start a browser and enter the following URL:
http://<hostname>:8888/jpa-example/index.faces
Where
<hostname> is the name of the computer you deployed the application to.
Start a browser and enter the following URL:
http://<hostname>:8080/jpa-example/ or
http://<hostname>:8080/jpa-example/index.jsp
Where
<hostname> is the name of the computer you deployed the application to.
This tutorial described a JSF Web application that manages persistence using JPA.
For more information, see:
JSR-220 Enterprise JavaBeans v3.0 Java Persistence API specification
This tutorial includes the following examples:
Structure of <EXAMPLE_HOME> and <TUTORIAL_HOME>
Persistence Unit in Persistence.xml
Acquiring the Entity Manager Factory
Creating an Order in ManagedOrderBean
Reading an Order in ManagedOrderBean
Updating an Order in ManagedOrderBean
Deleting an Order in ManagedOrderBean
Using a Named Query in ManagedInventoryBean
Using a Dynamic Query in ManagedInventoryBean
Using a Named Query in ManagedOrderBean
Using a Dynamic Query in ManagedOrderBean
Finding and Removing an Order in a Transaction in ManagedOrderBean