This article brings you some super practical basic Java tutorials? The detailed explanation of the 13 specifications of J2EE has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.
#Java learning continues, and many details need to be controlled one by one. Let’s share the 13 specifications (standards) of J2EE:
1. JDBC (Java Database Connectivity)
java database connection is a Java API used to execute SQL statements, which can Multiple relational databases provide unified access, which consists of a set of classes and interfaces written in Java language. JDBC provides a standard API for tool/database developers, based on which more advanced tools and interfaces can be built, enabling database developers to write database applications using pure Java APIs. With JDBC, send SQL to various relational data Statements are a very easy thing, JDBC should be very similar to the ODBC we have been exposed to before.
2. JNDI (Java Name and Directory Interface)
Java Naming and Directory Interface is a set of APIs for accessing naming and directory services in Java applications. Naming services associate names with objects so that we can access objects by name. Directory service is a naming service. In this service, objects not only have names but also attributes. It is an application-designed API that provides developers with a common, unified interface for finding and accessing various naming and directory services. Similar to JDBC, it is built on an abstraction layer. JNDI contains a large number of naming and directory services, uses common interfaces to access different types of services, can connect to multiple naming or directory services at the same time, establishes logical associations, and allows names to be associated with Java objects or resources without having to Know the physical ID of the object or resource.
3. EJB (Enterprise JavaBean)
EJB is Sun's JavaEE server-side component model. The design goal and core application is to deploy distributed applications. One of the reasons why J2EE technology has won widespread attention is EJB, which provides a framework to develop and implement distributed business logic, thereby significantly simplifying the development of scalable and highly complex enterprise-level applications. The EJB specification defines when and how EJB components interact with their containers, which are responsible for providing common services such as directory services, transaction management, security, resource pools, and fault tolerance. But it is worth noting here that EJB is not the only way to implement J2EE. Due to the openness of J2EE, all manufacturers can achieve the same goal in a parallel way with EJB.
4. RMI (Remote Method Invoke)
Remote method request, RMI protocol calls methods on remote objects. It uses serialization to transfer data between the client and the server. RMI is a lower-level protocol used by EJB. RMI has the advantages of object-oriented, movable attributes, security, easy to write and use, can connect to existing original systems, write once and run everywhere, distributed garbage collection, etc.
5. Java IDL/CORBA
The Universal Object Request Broker Architecture is a standard for software construction. With the support of Java IDL, developers can integrate Java and CORBA. They can create Java objects and make them deployable in a CORBA ORB, or they can create Java classes and make CORBA object clients deployable with other ORBs. The latter approach provides another way through which Java can be used to integrate your new applications with your old systems.
6. JSP (Java Server Pages)
is initiated by Sun Microsystems and co-created by many companies, allowing software developers to respond to client requests and dynamically generate HTML, Technical standard for Web pages in XML or other format documents. JSP technology uses Java language as a scripting language. JSP web pages provide an interface for the entire server-side Java library unit to serve HTTP applications. JSP enables Java code and specific predefined actions to be embedded in static pages. JSP syntax adds XML tags called JSP actions, which are used to call built-in functions. JSP is very similar to ASP. ASP is added on the basis of HTML. Net code, while JSP adds Java code on the basis of HTML. They are all dynamic web pages. The biggest advantage of JSP is that it is cross-platform. It can run not only on the Windows platform, but also on Linux or other operating systems.
7、Java Servlet
Servlet is a server-side Java application that is platform- and protocol-independent and can generate dynamic Web pages. It acts as the middle layer between client requests (web browsers or other HTTP client programs) and server responses (databases or applications on the HTTP server). Servlet is a server-side Java application located inside the Web server. Unlike traditional Java applications that are launched from the command line, Servlet is loaded by the Web server, which must contain a Java virtual machine that supports Servlet. Servlets extend the capabilities of a server by creating a framework for providing request and response services on the Web. When a client sends a request to the server, the server can send the request information to the servlet and let the servlet build the response that the server returns to the client. Servlets can be loaded automatically when a Web server is started or when a client requests a service for the first time. After loading, the servlet continues to run until other clients make requests. Servlets have a wide range of functions.
8. XML (Extensible Markup Language)
XML is a language that can be used to define other markup languages. It is a subset of the Standard Universal Markup Language and is used to mark electronic documents. Make it a structured markup language. It is used to share data in different business processes. The development of XML and Java are independent of each other, but the same goal it has with Java is platform independence.
9. JMS (Java Message Service)
JMS is the Java Message Service (Java Message Service) application programming interface. It is an API for message middleware (MOM) in the Java platform. Use Used to send messages between two applications or in a distributed system for asynchronous communication. The Java Message Service is a platform-independent API, and most MOM providers provide support for JMS. JMS enables you to send messages from one JMS client to another through a messaging service (sometimes called a message broker or router). A message is a type of object in JMS that consists of two parts: a header and a message body. The header consists of routing information and metadata about the message. The message body carries the application's data or payload.
10. JTA (java transaction Architecture)
JTA defines a standard API through which applications can access various transaction monitoring. JTA allows applications to perform distributed transactions - accessing and updating data on two or more network computer resources. The JDBC driver's JTA support greatly enhances data access capabilities. 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. Any of the following Java platform components can participate in a JTA transaction: JDBC connections, JDO PersistenceManager objects, JMS queues, JMS topics, Enterprise JavaBeans (EJBs), and a resource allocator compiled with the J2EE Connector Architecture specification.
11. JTS (java transaction Service API)
JTS is the basic implementation of CORBA OTS transaction monitoring. JTS specifies the implementation method of transaction management. The transaction manager supports java Transaction at a high level. API specification, and implements OMG OTS specification and Java impressions at a lower level. The JTS transaction manager provides transaction services for application servers, resource managers, standalone applications, and classmate resource managers.
12. JavaMail
JavaMail is an API used to access mail servers. It provides a set of abstract classes for mail servers, supporting not only SMTP servers, but also IMAP servers. Provides developers with programming interfaces related to email processing. It is an API released by Sun for processing email. It can easily perform some common email transmissions.
13. JAF (JavaBean Activation FrameWork)
JAF is a dedicated data processing framework that is used to encapsulate data and provide an interface for applications to access and operate data. The main function of JAF is to let Java applications know how to view, edit and print a data source. JavaMail uses JAF to process MIME-encoded email attachments. MIME byte streams can be converted into Java objects. Most applications do not need to use JAF directly.
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