SessionBean or javax. EntityBean interfaces. For the differences between these types of beans, see "Definition of an Entity Bean".
The ejbCreate method with parameters matching those of the create method defined of the home interface. Create the bean deployment descriptor. The deployment descriptor specifies properties for the bean. Create an ejb-jar file containing the bean, the remote and home interfaces, and the deployment descriptor. The ejb-jar file must define all beans within your application. EJBObject and javax. EJBHome interfaces extend java. This means that their methods can only use the data types allowed in RMI, and that methods in both interfaces must throw the java.
RemoteException exception. Creating the Remote Interface The remote interface of a bean provides an interface for the methods that the client will invoke. That is, the remote interface defines the methods that you implement for remote access. EJBObject extends java. RemoteException public abstract void remove throws java. Function Description getEJBHome Retrieves the object reference for the home interface associated with this particular bean.
Note that you cannot typecast the returned object to the home interface type. The handle can be serialized and used to re-establish a connection to the same object. With session beans, the connection is re-established as long as the bean instance is still active; with entity beans, the connection is re-established irregardless of whether the bean is active or not. This identifies that both objects are the same for all purposes. This, in turn, destroys the session bean instance if stateful.
The signature for each method in the remote interface must match the signature in the bean implementation. The remote interface must be declared as public. You do not declare public variables in the remote interface. Only the public methods are declared. Any exception can be thrown to the client, as long as it is serializable.
Runtime exceptions are transferred back to the client as a remote runtime exception. Example The following code sample shows a remote interface called Employee, which declares the getEmployee method, which will be implemented in the bean. The home interface should define the appropriate create method for your bean. The home interface specifies one or more create methods. For each create method, a corresponding ejbCreate method must be defined in the bean implementation. All of the create methods return the bean type; all of the ejbCreate methods return void.
The client invokes the create method declared within the home interface. The container turns around and calls the ejbCreate method, with the appropriate parameter signature, within your bean implementation.
The parameter arguments can be used to initialize the state of a new EJB object. EJBHome extends java. The methods in the EJBHome interface are implemented by the container. A client can remove an EJB object using the remove methods defined in either of its home or remote interfaces.
All create methods must throw the following exceptions: javax. CreateException either java. RemoteException or javax. See the Oracle9i Java Tools Reference for a full description of deployejb. Example The following code sample shows a home interface called EmployeeHome.
The create method contains no arguments. Some methods in the Employee class can throw the EmpException exception. For an exception to be transported from the object to the client, you need to define a class for the exception. The following code defines an exception class and is found in EmpException. The bean contains the business logic for your bean.
It implements the following methods:. The bean in the example application consists of one class, EmployeeBean , that retrieves an employee's information.
The ejbCreate methods that corresponds to the create methods declared in the home interface. The container invokes the ejbCreate method when the client invokes the corresponding create method.
This example implements the SessionBean interface. Basically, a session bean is used for process oriented beans--those beans that perform tasks to achieve an end. Entity beans are complex remote objects that are organized around persistent data. See "Definition of an Entity Bean" for more information on the differences between the two types of beans. The session bean implements the javax. SessionBean interface, which has the following definition:.
At a minimum, an EJB must implement the following methods, as specified in the javax. SessionBean interface:. This method performs any required clean-up, for example closing external resources such as file handles. The container calls this method after the bean creation. The enterprise bean can store the reference to the context object in an instance variable, for use in transaction management. Beans that manage their own transactions can use the session context to get the transaction context.
Using setSessionContext This method is used by a session bean instance to retain a reference to its context. Session beans have session contexts that the container maintains and makes available to the beans. The bean may use the methods in the session context to make callback requests to the container. The container invokes setSessionContext method, after it first instantiates the bean, to enable the bean to retrieve the session context. The container will never call this method from within a transaction context.
If the bean does not save the session context at this point, the bean will never gain access to the session context. When the container calls this method, it passes the reference of the SessionContext object to the bean.
The bean can then store the reference for later use. The following example shows the bean saving the session context in the sessctx variable. A bean needs the session context when it wants to perform the operations listed in Table This is only valid for beans that have been designated transactional.
Bean Implementation Example The following code implements methods of a session bean called EmployeeBean. The SessionBean interface methods are implemented along with the public methods declared in the remote interface. Then the setInt method is used to associate the empNumber input parameter for the getEmployee method with the'? This is identical to the JDBC code that you would write in a client application.
All EJB clients perform the following to instantiate a bean, invoke its methods, and destroy the bean:. Create instances of the bean in the server through the home interface. Invoking the create method on the home interface causes a new bean to be instantiated. This returns a bean reference to the bean's remote interface.
Invoke the methods defined in the remote interface. The container forwards the requests to the instantiated bean. After the bean is no longer needed, invoke the remove method to destroy the bean. All rights reserved, c insoso. Java Class Stateless in javax. RC1 [JAR] easybeans-core RC2 [JAR] easybeans-core RC3 [JAR] easybeans-core RC3 [JAR] easybeans-uberjar-hibernate RC3 [JAR] easybeans-uberjar-openjpa RC3 [JAR] easybeans-uberjar-toplink-essentials Final [JAR] hawkular-apm-agent-rest Final [JAR] hawkular-apm-performance-server Final [JAR] hawkular-apm-server-kafka Final [JAR] hawkular-btm-agent-rest Final [JAR] jadort-console Beta3Update1 [JAR] jboss-ejb-api CR1 [JAR] jboss-ejb-api CR2 [JAR] jboss-ejb-api GA [JAR] jboss-ejb-api Final [JAR] jboss-ejb3x Connect and share knowledge within a single location that is structured and easy to search.
Some solutions implied adding the libraries j2ee. I am using eclipse kepler on a Windows 7 x64 machine. The file must be manually downloaded and added to the project build path.
The java ee 7 api can be found here. Alternatively, a maven dependency can be used:. If you're using Eclipse, its classpath may be pointing to the standard Java libraries and not the Enterprise libraries.
You can try two things:. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Cannot import javax. Asked 7 years, 10 months ago. Active 2 years, 7 months ago.
Viewed 55k times.
0コメント