There are many people who are familiar with Java, but for j2ee, many people probably have heard it for the first time. So what is this j2ee ? What is it inextricably linked to Java?
1. What is j2ee?
To know what j2ee is, you must first know the three major branches of Java. Java is divided into three systems, namely Java SE (Standard Edition), JavaEE (Enterprise Edition), and Java ME (Micro Edition). From this point of view, j2ee is one of the three major branches of Java.
j2ee is a set of technical architectures that are completely different from traditional application development, including many components, which can simplify and standardize the development and deployment of application systems, thereby improving portability, security and reuse value.
The core of j2ee is a set of technical specifications and guidelines. All kinds of components, service architectures and technical levels included in it have common standards and specifications, so that there is good compatibility between different platforms that follow the j2ee architecture. It solves the dilemma that the information products used in the back-end of the enterprise were incompatible with each other, and it was difficult to communicate with each other inside or outside the enterprise.
A j2ee component differs from a "standard" Java class in that it is assembled in a j2ee application, has a fixed format and conforms to the j2ee specification, and is managed by the j2ee server. The j2ee specification defines j2ee components as follows: client applications and applets are components that run on the client; Java Servlet and Java Server Pages (JSP) are Web components that run on the server; Enterprise Java Bean (EJB) components are components that run on the server side business components. Tutorial from: http://www.285868.com/jiaocheng/jpc/show-8539.html
2. What are the advantages of j2ee?
① Simplified structure
Since j2ee is based on the Java programming language, it provides write once, run anywhere portability, a model that is supported by all servers that follow the j2ee standard. In addition, j2ee also supports heterogeneous environments. j2ee based applications do not depend on any specific operating system, middleware or hardware.
②Improve development efficiency
Due to the use of component technology, application development can be divided according to the developer's skills and developed in parallel, providing overall development efficiency. Many of these tasks can be performed simultaneously to accelerate the development of the application.
③Strong portability
In addition to the inherent portability of the Java language, j2ee provides a standardized set of application programming interfaces, which enables developers to port from one operating environment to another without rewriting source code.
④Easy to maintain
Component-based design simplifies application maintenance. Since components can be updated and replaced independently, new functionality can be easily implemented by updating specific components in the application.
⑤ Scalability
Applications based on the j2ee platform can be deployed on various operating systems, such as high-end UNIX or other mainframe systems. The j2ee supplier provides a wide range of load balancing strategies, which can eliminate bottlenecks in the system, allow multiple servers to be integrated and deploy, and achieve high system scalability.