英语翻译Data Access TechnologiesDatabase access has been part of

英语翻译
Data Access Technologies
Database access has been part of Java since Sun added the Java Database Connectivity (JDBC) API as an add-on to Java 1.0.Since then,Sun has also added Enterprise JavaBeans (EJB) and most recently Java Database Objects (JDO) to Java.That isn't all; Sun is only one of the many organizations supporting database access from Java.Numerous vendors have sprung up over the years to provide JDBC implementations and Object-Relational Mapping (O/R) frameworks for Java.
The good news is that there are a lot of choices for data access.That's also the bad news.In this section we'll sort out the choices by dividing them up into four categories starting with the simplest and ending with the most sophisticated.The five data access technologies,from simplest to most sophisticated are
 JSP tags for SQL
 JDBC
 O/R frameworks
 JDO
 EJB Entity Beans
When you choose a data access technology,you should consider both the nature of the web application that you're developing and the skills of your development and support teams.Generally speaking,if you have simple requirements and a less experienced team,then you should favor the simple end of the spectrum.If you have more complex requirements and a more experienced team you should favor the sophisticated side.Here are some questions to consider:
 Does your application have fairly simple database access requirements?Perhaps you need only to display a couple of reports based on information in a database.For simple applications,you might want to avoid the learning curve,complexity,and overhead of a more sophisticated data access technology.
 Will your application have a complex Java object model that must be persisted to a database?If so,you might find that you really cannot do without the sophisticated automated object-relational mapping capabilities of an O/R framework or of EJB Container Managed Persistence (CMP).
 Is your application one that is highly transactional,requires high availability,and is likely to support a very large number of concurrent users?If so,you might find that you need the
在这个里面