A summary of 13 specifications of the Java EE

Java EE is the beginning of our journey into Java, and it will open up this magical tour, which is a simple, cross-platform, object-oriented, distributed, interpreted, robust, secure, structured neutral, portable, multi-threaded, dynamic language with excellent performance. Not just free open source, but also a cross-platform advantage.

Before learning Java Specifically, let's learn the EE.

　1. What is the Java EE?? Background　　

We often hear such a sentence: " first-class enterprise to do the standard, second-rate enterprises do brand, three-stream enterprises to do products!" " what does that mean?" Three-stream enterprise products are simply the simplest of the process of converting labor into commodities; second-rate enterprises to do the brand, is in the basis of doing goods, to establish a brand sense of honor and responsibility, such as many brands like Apple and so on the mobile phone brand, you are willing to buy it's brand, because they are good quality, have connotation, high aesthetic , first-class enterprises to do the standard, which is more than the concept of making a brand, that they are beyond the establishment of the brand at that stage, is widely recognized within and outside the industry and as an effort to imitate the object of catching up, they make things can be as the direction of peer efforts and reference.

In our computer programming world there are also standards or norms that introduce the concepts before introducing the Java EE specification.

? Concept　

EE (Java 2 Enterprise Edition) is a solution for enterprise-class applications built on the Java 2 platform. The foundation of the Java 2 platform, which not only has all the features of the J2SE platform, but also provides comprehensive support for ejb,servlet,jsp,xml and other technologies, the ultimate goal is to become an architecture that supports enterprise application development and simplifies the development of enterprise solutions. Complex issues such as deployment and management. In fact, Java EE has become an industry standard and preferred platform for enterprise-level development. Java not a product, but a series of standards.

The Java EE, which is a standard proposed by Sun, is called "realization", in which one of the Sun's Java EE development packages you download is "implemented", and Jboss,weblogic,websphere is an "implementation" of the Java EE standard. Because Jboss,weblogic,websphere has its own Java EE API, it can be implemented without using Sun's Java EE.

In short: Java is an enterprise-level development platform, I personally for Java the understanding is that this is a standard as long as it conforms to the Java standard of a variety of developed plug-ins, frameworks, etc., can be ported to this platform. This is the java EE. He is not a product. But a standard.

　2.13 Specifications of the Java EE? JDBC (Java databaseconnectivity): Java database connection　　

JDBC provides Java developers with an industry-standard API to establish database-independent connections between Java applications and relational databases, which means that the JDBC API provides a unified approach to accessing different databases, and we find that JDBC is actually similar to ODBC , like ODBC, JDBC has blocked some details for developers, andJDCB access to the database is platform agnostic .

? JNDI (Java naming anddirectoryinterfaces): Java Naming and Directory interface　　

Jndi is a Java application design interface (API) that provides developers with a common, unified way to find and access naming and directory services, which is built on DNS (domain Name System, domainname), LDAP (LDAP is a Lightweight Directory Access Protocol, The English name is Lightweightdirectory Access Protocol, which is generally referred to as LDAP. ) and other services.

? EJB (Enterprise JavaBean) Business class Java Beans　　

One of the reasons why EE technology has won wide attention is EJB. It provides a framework for developing and implementing distributed business logic, which significantly simplifies the development of scalable and highly complex enterprise-class applications. The EJB specification defines when EJB components interact with their containers. Containers are responsible for providing common services, such as directory services, transaction management, security, resource pooling, and fault tolerance.

In general, EJB is the Java component that implements distributed business logic, and "enterprise" means the extensibility, reliability, availability, security, transactional, and distribution of the application. EJB provides customers with a distributed and deployable business logic service, and has a good interface to execute in a container that provides management and control services. and is reusable between application services.

? RMI (remote Methodinvocation): Remoting method Invocation　　

Remote Method Invocation (RMI) is a Java-based distributed programming model that allows objects to use stubs (.) To call objects on a remote host to block a client, you must provide some way to emulate the local object, which is called a stub, and the stub is responsible for receiving local method calls. and delegate them to their specific implementation objects) and Skeleton (the Skeleton interface is used solely for RMI implementations, and the Skeleton of the remote object is a server-side entity that assigns calls to the actual remote object implementation. Obsolete) calls the remote object, in addition RMI uses serialization to transfer data between two objects by value.

? Javaidl/corba (javainterfacedefiniyion Language/common object request broker Architecture): Java Interface Definition language/Common Object Request Agent architecture 　　

With the support of Java IDL, developers can integrate Java with CORBA. They can create Java objects and make them available in the CORBA Orb (Orb (Object request Broker) object requests Escrow), or they can create Java classes as CORBA object clients that are expanded with other orbs. The latter approach provides another way through which you can integrate with your new applications and legacy systems.

? JSP (Java Server Pages)　

JSP is run on the server side, the dynamic publishing language, is the Java Servlet Technology development and natural expansion, will be transformed into a servlet, according to the client request to create a Dynamic Web page text file, is the "view" component in the Java EE, which includes HTML tags, JSP tags, and Java code.

? Java Servlet　　

A Servlet is a small Java program that extends the functionality of a Web server. As a server application, when requested, this and CGI Per (Common Gateway Interface CGI, is a set of standard definitions to exchange information between the Web server and the custom script. ) scripts are similar. Servlets provide much more functionality than JSPs, but they are implemented in different ways. JSPs are usually embedded in a small amount of Java code in most HTML code, and the servlet is all written in Java and generates HTML.

Further, the servlet is a Java class that deals with Web clients based on the request/Response pattern of the HTTP protocol. The HTTP servlet is characterized by container management, which generates dynamic content that can store customer data in a local session.

　　Note: Applets: Small applications are programs written in the Java programming language that can be included in the HTML (one application of the standard Universal Markup Language) page, in much the same way that a page contains images.

? XML (extensible Markuplanguage) Extensible Markup Language　　

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.

It is the platform independence, so with the combination of Java will make its development more downwind.

? JMS (Java messageservice): Java Messaging Service　　

JMS is a middleware for and object-oriented messages (middleware is a standalone system software or service program, and distributed application software uses this software to share resources among different technologies. The middleware is located on the client/server operating system and manages the computer resources and network traffic. Is software that connects two standalone applications or standalone systems. ) The application interface that communicates with each other. JMS is a Java API that provides a common way to create, send, receive, and read messages from an enterprise information communication system. And the interface supports a point-to-point model, a publish/subscribe model, a guaranteed message distribution, a transactional session, and so on.

? JTA (Java Transaction API): Java Transaction API　　

JTA defines a standard API that allows applications to access various transaction monitoring, and JTA transactions are more powerful than JDBC transactions. A JTA transaction can have multiple participants, while a JDBC transaction is limited to a single database connection. It also provides distributed transaction services for the Java EE platform.

　　The Java transaction API can span including EJB access, JDBC connections, and JMS connections.

? Jts:java Transactionservice,java Transaction Services　　

Java Transactionservice is a key element of the EE architecture. It is combined with the Java Transaction API, enabling us to build distributed applications that are very robust for a variety of systems and network failures.

A distributed Transaction (Distributedtransaction) includes a transaction manager (transaction manager) and one or more resource managers (Resource manager). A Resource Manager (Resource Manager) is any type of persisted data store. The transaction manager (transaction Manager) undertakes the responsibility of communicating with each other in the unit of the transaction.

? JavaMail　　

JavaMail is an API for accessing mail servers that provides an abstract class of mail servers. Not only support SMTP servers, but also IMAP servers.

? JAF (JavaBeans activationframework): JavaBeans Active bedstead　　

JAVA Mail is an API for accessing mail servers, and it provides an abstract class for a set of mail servers. Not only support the SMTP server, but also support IMAP server Java mail to use the Java beansactivation FRAMEWORK (JAF) to handle mime-encoded message attachments. The MIME byte stream can be converted to a Java object or converted from a Java object. As a result, most applications do not need to use JAF directly.

　　JAF is a dedicated data processing framework that is used to encapsulate data and to access and manipulate data interfaces for applications. JFA's primary role is to let the Java application sequence know how to view, edit, and print a data source.

3. Summary

For Java 13 Specifications is complete, because it is just contact, for this piece of learning is a little strange, in the old knowledge to learn new knowledge, the establishment of knowledge network, the knowledge in series, I believe will soon be familiar, here is just their initial study, about more summary and understanding, will be in the following learning to continue to deepen, hope that after understanding further deepened.

In conclusion: TheEE is not a product, but a series of standards.

A summary of 13 specifications of the Java EE