13 technical specifications in J2EE

The J2EE platform provides a complete set of services ( Services ), ApplicationProgramInterface ( APIS And protocol, which is based on Web Multi-tier applications provide Function Support. J2EE In 13 A brief description of technical specifications ( Limited space, which can only be briefly described here ):
1. JDBC (Java database connectivity ):
JDBC API It provides a unified way to access different databases, such ODBC Same, JDBC Some details are blocked for developers. In addition, Jdcb Database Access is also platform-independent.  
2. JNDI (Java name and Directory Interface ):
JNDI API Used for executing the name and directory service. It provides a consistent model to access and operate enterprise-level resources such DNS And LDAP , A local file system, or an object on the application server.

3. EJB (Enterprise JavaBean ): 
J2EEOne of the reasons why technology has won wide attention is EJB . They provide a framework for developing and implementing distributed business logic, significantly simplifying the development of scalable and highly complex enterprise-level applications. EJB Standardized Definition EJB When and how components interact with their containers. Containers are responsible for providing public services, such as directory services, transaction management, security, resource buffer pools, and fault tolerance. However, it is worth noting that, EJB Not Implemented J2EE The only way. It is precisely because J2EE Open, so that some vendors can EJB Parallel methods to achieve the same purpose.
4. RMI (Remote Method invoke ):
As its name indicates, RMI The Protocol calls the method on a remote object. It uses serialization to transmit data on the client and server. RMI Is EJB The underlying protocol used.
5. Java IDL/CORBA:
In Java IDL With the support of, developers can Java And CORBA Integration. They can create Java Object and make it available in CORBA ORB Expand , Or they can create Java And Orb Expanded together CORBA Target customers. The latter method provides another method through which Java It can be used to integrate your new applications with old systems.
6. jsp (Java Server Pages ):
JSP Page Html CodeAnd Java Code. After the server is requested by the client on the page Java Code, and then the generated Html The page is returned to the browser of the client.
7. Java Servlet:
Servlet Is a small Java Program, it extends Web Server features. As a server-side application, it is executed when it is requested. Cgi Perl The script is similar. Servlet Most of the functions provided are JSP Similar, but the implementation method is different. JSP Usually the majority Html Embed a small number Java Code, and Servlets All Java Write and generate Html .
8. XML (Extensible Markup Language ):
XML Is a language that can be used to define other Markup languages. It is used to share data in different business processes. XML Development and Java Is independent of each other, but it and Java The same goals are platform independence. By adding Java And XML You can get a perfect solution with platform independence.
9. JMS (Java Message Service ):
MS Is an application interface used to communicate with message-oriented middleware. (API) . It supports both point-to-point domains and publishing. / Subscription (Publish/subscribe) And supports the following types: accepted message transmission , Transmission of transactional messages, consistent messages, and persistent subscribers. JMS It also provides another way to integrate your application with the old background system.
10. JTA (Java transaction architecture ):
JTA Defines a standard API The application system can access various transaction monitoring.
11. JTs (Java Transaction Service ):
JTs Yes CORBA OTS Basic Implementation of transaction monitoring. JTs Specifies the implementation method of the Transaction Manager. The transaction manager is supported at the high-level level. Java transaction API (JTA) Specification, and at a lower level Omg ots Specification Of Java Image. JTs The transaction manager provides transaction services for application servers, resource managers, independent applications, and communication resource managers.
12. javamail:
Javamail Is used to access the email server API It provides an abstract class for the mail server. Not only SMTP Server. IMAP Server.
13. JAF (JavaBeans activation framework ):
Javamail Exploitation JAF To process Mime Encode the email attachment. Mime The byte stream can be converted Java Object, or convert from Java Object. Most applications do not need to be used directly. JAF .