qr code scanner java app Starting a Java Persistence project in Java

Generating QR Code in Java Starting a Java Persistence project

Starting a Java Persistence project
QR Code ISO/IEC18004 Generation In Java
Using Barcode generation for Java Control to generate, create QR Code image in Java applications.
www.OnBarcode.com
Recognizing Denso QR Bar Code In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
class="org.jboss.resource.adapter.jdbc.local.LocalTxDataSource"> <property name="jndiName">java:/HelloWorldDS</property> <!-- HSQLDB --> <property name="driverClass"> org.hsqldb.jdbcDriver </property> <property name="connectionURL"> jdbc:hsqldb:hsql://localhost </property> <property name="userName">sa</property> <property <property <property <property name="minSize">0</property> name="maxSize">10</property> name="blockingTimeout">1000</property> name="idleTimeout">100000</property>
Quick Response Code Generator In Java
Using Barcode generator for Java Control to generate, create QR Code image in Java applications.
www.OnBarcode.com
Encoding Data Matrix 2d Barcode In Java
Using Barcode creation for Java Control to generate, create Data Matrix image in Java applications.
www.OnBarcode.com
<property name="transactionManager"> <inject bean="TransactionManager"/> </property> <property name="cachedConnectionManager"> <inject bean="CachedConnectionManager"/> </property> <property name="initialContextProperties"> <inject bean="InitialContextProperties"/> </property> </bean> <bean name="HelloWorldDS" class="java.lang.Object"> <constructor factoryMethod="getDatasource"> <factory bean="helloWorldDatasourceFactory"/> </constructor> </bean> </deployment>
Code 128 Code Set C Creator In Java
Using Barcode drawer for Java Control to generate, create Code128 image in Java applications.
www.OnBarcode.com
Barcode Maker In Java
Using Barcode generator for Java Control to generate, create Barcode image in Java applications.
www.OnBarcode.com
Again, the XML header and schema declaration aren t important for this example. You set up two beans: The first is a factory that can produce the second type of bean. The LocalTxDataSource is effectively now your database connection pool, and all your connection pool settings are available on this factory. The factory binds a managed datasource under the JNDI name java:/HelloWorldDS. The second bean configuration declares how the registered object named HelloWorldDS should be instantiated, if another service looks it up in the JNDI registry. Your Hello World application asks for the datasource under this name, and the server calls getDatasource() on the LocalTxDataSource factory to obtain it.
Data Matrix ECC200 Encoder In Java
Using Barcode printer for Java Control to generate, create Data Matrix image in Java applications.
www.OnBarcode.com
Draw Leitcode In Java
Using Barcode generation for Java Control to generate, create Leitcode image in Java applications.
www.OnBarcode.com
Starting a project
Denso QR Bar Code Encoder In Objective-C
Using Barcode printer for iPhone Control to generate, create Quick Response Code image in iPhone applications.
www.OnBarcode.com
Make QR-Code In None
Using Barcode maker for Font Control to generate, create QR image in Font applications.
www.OnBarcode.com
Also note that we added some line breaks in the property values to make this more readable you shouldn t do this in your real configuration file (unless your database username contains a line break). Configuring the persistence unit Next, you need to change the persistence unit configuration of the Hello World application to access a managed JTA datasource, instead of a resource-local connection pool. Change your WORKDIR/etc/META-INF/persistence.xml file as follows:
GTIN - 13 Drawer In None
Using Barcode encoder for Software Control to generate, create EAN 13 image in Software applications.
www.OnBarcode.com
Code 39 Extended Reader In C#
Using Barcode scanner for Visual Studio .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
<persistence ...> <persistence-unit name="helloworld"> <jta-data-source>java:/HelloWorldDS</jta-data-source> <properties> <property name="hibernate.show_sql" value="true"/> <property name="hibernate.format_sql" value="true"/> <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/> <property name="hibernate.hbm2ddl.auto" value="create"/> </properties> </persistence-unit> </persistence>
DataMatrix Recognizer In .NET Framework
Using Barcode decoder for Visual Studio .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
USS Code 39 Printer In None
Using Barcode generator for Online Control to generate, create Code-39 image in Online applications.
www.OnBarcode.com
You removed many Hibernate configuration options that are no longer relevant, such as the connection pool and database connection settings. Instead, you set a <jta-data-source> property with the name of the datasource as bound in JNDI. Don t forget that you still need to configure the correct SQL dialect and any other Hibernate options that aren t present in default.persistence.properties. The installation and configuration of the environment is now complete, (we ll show you the purpose of the jndi.properties files in a moment) and you can rewrite the application code with EJBs. Writing EJBs There are many ways to design and create an application with managed components. The Hello World application isn t sophisticated enough to show elaborate examples, so we ll introduce only the most basic type of EJB, a stateless session bean. (You ve already seen entity classes annotated plain Java classes that can have persistent instances. Note that the term entity bean only refers to the old EJB 2.1 entity beans; EJB 3.0 and Java Persistence standardize a lightweight programming model for plain entity classes.)
Read Code 3/9 In Visual Studio .NET
Using Barcode scanner for Visual Studio .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
QR Code ISO/IEC18004 Encoder In Visual Basic .NET
Using Barcode creation for Visual Studio .NET Control to generate, create QR Code ISO/IEC18004 image in VS .NET applications.
www.OnBarcode.com
Starting a Java Persistence project
Paint Barcode In Objective-C
Using Barcode creator for iPad Control to generate, create Barcode image in iPad applications.
www.OnBarcode.com
Making Code39 In None
Using Barcode drawer for Software Control to generate, create USS Code 39 image in Software applications.
www.OnBarcode.com
Every EJB session bean needs a business interface. This isn t a special interface that needs to implement predefined methods or extend existing ones; it s plain Java. Create the following interface in the WORKDIR/src/hello package:
Scan ANSI/AIM Code 39 In None
Using Barcode decoder for Software Control to read, scan read, scan image in Software applications.
www.OnBarcode.com
GTIN - 128 Creation In None
Using Barcode printer for Online Control to generate, create GTIN - 128 image in Online applications.
www.OnBarcode.com
package hello; public interface MessageHandler { public void saveMessages(); public void showMessages(); }
A MessageHandler can save and show messages; it s straightforward. The actual EJB implements this business interface, which is by default considered a local interface (that is, remote EJB clients cannot call it); see listing 2.15.
Listing 2.15 The Hello World EJB session bean application code
package hello; import javax.ejb.Stateless; import javax.persistence.*; import java.util.List; @Stateless public class MessageHandlerBean implements MessageHandler { @PersistenceContext EntityManager em; public void saveMessages() { Message message = new Message("Hello World"); em.persist(message); } public void showMessages() { List messages = em.createQuery("select m from Message m order by m.text asc") .getResultList(); System.out.println(messages.size() + " message(s) found:"); for (Object m : messages) { Message loadedMsg = (Message) m; System.out.println(loadedMsg.getText()); } } }
Starting a project
There are several interesting things to observe in this implementation. First, it s a plain Java class with no hard dependencies on any other package. It becomes an EJB only with a single metadata annotation, @Stateless. EJBs support containermanaged services, so you can apply the @PersistenceContext annotation, and the server injects a fresh EntityManager instance whenever a method on this stateless bean is called. Each method is also assigned a transaction automatically by the container. The transaction starts when the method is called, and commits when the method returns. (It would be rolled back when an exception is thrown inside the method.) You can now modify the HelloWorld main class and delegate all the work of storing and showing messages to the MessageHandler. Running the application The main class of the Hello World application calls the MessageHandler stateless session bean after looking it up in the JNDI registry. Obviously, the managed environment and the whole application server, including the JNDI registry, must be booted first. You do all of this in the main() method of HelloWorld.java (see listing 2.16).
Copyright © OnBarcode.com . All rights reserved.