Java EE Basic article--13 specifications

Background:

1, enterprise application framework needs, in many enterprise-level applications. For example, database connection, mail service, transaction processing and so on are some common enterprise requirements module, these modules assume that each time in development by the developer to complete, will lead to long development cycle and poor code reliability problems. So many large companies have developed their own general-purpose module services.

These service software families are collectively referred to as middleware.

2, in order to general need to put forward norms, otherwise can not reach the general, on the basis of the above requirements, many companies have developed their own middleware, but its communication with users are different, resulting in the user can not be different from each company's middleware assembled in a piece for their own service. thus creating bottlenecks.

The concept of the standard was then proposed.

In fact, it is a set of standards for Java technology.

Brief introduction:

Java 2 Platform, EnterpriseEdition is a Java platform designed for large enterprise host-level computing types. Sun Microsystems (along with its industrial partners, such as IBM) designed the Java EE. This simplifies application development in a thin customer-level environment. Because of the creation of standard reusable module components, as well as the construction of a hierarchy that can proactively handle many aspects of programming. The Java EE simplifies the development of applications. It also reduces the need for programming and for trained apes. Increase portability, security, and reuse value .

The Java EE is like a screw and nut relationship, suppose we want to buy a thread specification for st2.9-st6.3 hex Flange self-drilling self-tapping screw, we can buy the screws or nuts that meet our needs, regardless of where we buy the screw, and the Java EE defines the standard.

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Component Standard Specification

1. JDBC (Java databaseconnectivity)

The JDBC API provides a unified path to access different databases, like ODBC, where the JDBC developer masks some detail issues, and JDBC's access to the database is platform agnostic.

JDBC can do three things: establish a connection to the database, send a statement that operates the database, and process the results.

With JDBC, sending SQL statements to various relational data is a very easy thing to do. In other words, with the JDBC API. You do not have to write a program specifically for access to the Sybase database and write a program specifically to access the Oracle database. Or to access the Informix database and write a program and so on, the program ape just needs to write a program with the JDBC API, it can send SQL calls to the corresponding database.

At the same time. Combining the Java language and JDBC makes it unnecessary for a program ape to write different applications for different platforms, simply by writing the program once and allowing it to execute on whatever platform, which is the Java language's "write once, execute everywhere" advantage. Second, it enhances the efficiency and speed of access to data.

2. JNDI (Java Name and Directoryinterface)

The JNDI API is used to run the name and folder Services . it provides a consistent model for accessing and manipulating enterprise-class resources DNS and the LDAP, Local file System , or an object in the application server .

An application-designed API that provides developers with a common, unified interface to find and access various naming and folder services. JDBC-like is built on the abstraction layer.

3. EJB (Enterprise JavaBean)

EJB is the Sun's javaeeserver-side component model. The design goal and core application is to deploy distributed applications. The simple thing is to package a program that has already been written (that is, a class) and put it on the server. With the advantages of Java cross-platform, distributed systems deployed with EJB technology are not limited to specific platforms. EJB (Enterprise JavaBean) is part of the Java EE (Java). Defines a standard for developing component-based enterprise multi-application. Features include network service support and core development tools (SDKs). In the Java EE, Enterprise Java Beans (EJB) is referred to as an enterprise bean. Is the core code of Java. Each is the session bean, the entity bean, and the message-driven bean (Messagedriven bean), describing the criteria to be addressed in building the application component.

4. RMI (Remote Method Invoke)

The remote method requests that the RMI protocol invokes methods on the remote object . it uses a serialized way to pass data between the client and the server . RMI is a lower-level protocol that is used by EJBs .

5, Java Idl/corba ( Common Object request Proxy architecture is a standard for software building )

in theJava IDLsupported by,developers will be able toJavaand theCORBAIntegrate together.They can createJavaobject and make it available in theCorbaorbExpand in,or they can also createJavaclass and and otherORBto unfold together.CORBAObject Customer.The latter approach provides a second approach,through itJavacan be used to assemble your new application with the old system.

6. JSP

JSP technology is a bit like ASP technology. It is a JSP file that is inserted into the Java program Segment (scriptlet) and JSP tag (tag) in the traditional Web page HTML (a subset of standard Universal Markup Language) files (*.htm,*.html). The suffix is named (*.jsp). Web applications developed with JSP are cross-platform and can be executed under Linux. can also be executed on other operating systems.

JSP page by HTML (Standard Universal Markup Language application) code and embedded Java code. Server in after the page is requested by the client Java code for processing , then the generated HTML The page is returned to the client browser.

7. Java Servlet

Servlet is a kind of smallJavaprogram,It expands theWebfeatures of the server.as an application of a server,Start running when requested,this andCGI Perlscripts are very similar. Servletthe features provided are mostly andJSPsimilar,It 's just a different way of achieving it. JSPis generally the majority ofHTMLthe code embeds a small number ofJavaCode,andservletAll byJavawritten and generatedHTML.

8. XML

XML (a subset of standard generic markup languages) is a language that can be used to target other markup languages. It is used to share data in different business processes. The development of XML is independent of Java, but the same goal it has with Java is platform independence .

9. JMS

MSis an application interface for communicating with each other in the middleware for object-oriented messages.it supports both point-to-point domains,also supports the publication/domain of the subscription type,and the following types of support are available:Message Delivery,delivery of transactional messages,consistent messaging and persistent subscriber support. JMSThere is also a way to integrate the new system with the legacy backend system.

10, JTA

JTA defines a standard API that enables applications to access various transaction monitoring.

11, JTS

JTSis aCORBA OTSbasic implementation of transaction monitoring. JTSThe implementation method of the transaction management is stipulated.The transaction manager is supported at the high leveljava Transaction APISpecification,and implemented at lower levelsomgots Specificationand theJavaImpressions. JTStransaction manager for Application Server,Resource Manager,independent Application and peer Explorer provides transactional services.

12, JavaMail

JavaMail is used to access the mail server API, it provides a set of abstract classes for mail server . not only support SMTP Server , also supports IMAP Server .

13, JAF (JavaBeans activationframework)

JavaMail uses JAF to handle MIME-encoded message attachments. MIME byte streams can be converted to Java objects, and most applications do not have to use the J AF.

Summarize:

The 13 specifications of the Java EE are more abstract things. In general, the Java EE is an industry standard for developing enterprise-class applications with the development of the technology, which is the product of Java technology adapting and promoting enterprise-level application process.

As we screw the nut specifications. These specifications are convenient for our development.

Java EE Basic article--13 specifications