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Bài giảng Lập trình mạng nâng cao: EJB: Entity Bean - Nguyễn Xuân Vinh

This chaper describe the concept of persistence, define entity beans, list the features offered by entity beans, compare entity and session beans, explain Message-Driven Beans. | EJB: Entity Bean Presenter: Nguyễn Xuân Vinh Information Technology Faculty Nong Lam University ACCP2005/EJB 2.0/ Session 5 / of 33 Session Objectives Describe the concept of persistence. Define entity beans. List the features offered by entity beans. Compare entity and session beans. Explain Message-Driven Beans. ACCP2005/ Developing Enterprise Applications 2.0 / Session 5/ of 34 ACCP2005/EJB 2.0/ Session 5 / of 33 Review of Session 4 In Session 4 we discussed: Definition of a Stateful Session Bean. The characteristics of a Stateful Session Bean. How to program Stateful session beans. Difference between Stateless and Stateful Session beans. ACCP2005/EJB 2.0/ Session 5 / of 33 Persistence Persistence Java Object Serialization Three ways to make an object persistent Object Relational Mapping Object database Persistence Database Storage Obj 1 Obj 2 Persistence Objects Storage Storage ACCP2005/ Developing Enterprise Applications 2.0 / Session 5/ of 34 This slide is self explanatory. It states the three ways in which objects can be made persistent ACCP2005/EJB 2.0/ Session 5 / of 33 Java Object Serialization Object 1 Object 2 Object n State of the object Compact representation Marshall an object graph into a compact representation Serialization of object graph into byte stream Developer pushes data over the network or saves the stream to a storage Byte Stream ACCP2005/ Developing Enterprise Applications 2.0 / Session 5/ of 34 The slide is self explanatory. The state of the object is saved to permanent storage. This is done by object serialization. Here an object graph is marshaled into a compact representation . When the object graph is serialized, it is converted into a byte stream. The developer can then push data over the network or save the stream to a storage such as a file system, database or JNDI tree. However, object serialization has some drawbacks. For example, A file system stores a huge amount of serializable employee objects. . | EJB: Entity Bean Presenter: Nguyễn Xuân Vinh Information Technology Faculty Nong Lam University ACCP2005/EJB 2.0/ Session 5 / of 33 Session Objectives Describe the concept of persistence. Define entity beans. List the features offered by entity beans. Compare entity and session beans. Explain Message-Driven Beans. ACCP2005/ Developing Enterprise Applications 2.0 / Session 5/ of 34 ACCP2005/EJB 2.0/ Session 5 / of 33 Review of Session 4 In Session 4 we discussed: Definition of a Stateful Session Bean. The characteristics of a Stateful Session Bean. How to program Stateful session beans. Difference between Stateless and Stateful Session beans. ACCP2005/EJB 2.0/ Session 5 / of 33 Persistence Persistence Java Object Serialization Three ways to make an object persistent Object Relational Mapping Object database Persistence Database Storage Obj 1 Obj 2 Persistence Objects Storage Storage ACCP2005/ Developing Enterprise Applications 2.0 / Session 5/ of 34 This slide is .