1, different fields:
Javase is the standard version of the platform and can be used in any field.
Javaee is an enterprise version of the platform, which is mainly used by enterprises.
2. Different roles:
Javase provides development tools, software libraries and Java virtual machines for developing and running Java software. It is also the foundation of Java2 platform, Enterprise Edition and Java web service.
JavaEE not only consolidates many advantages of the standard version, such as "write once, run anywhere", JDBC API for easy access to database, CORBA technology and security mode for protecting data in Internet applications.
At the same time, it also provides comprehensive support for EJB(Enterprise JavaBeans), Java Servlets API, JSP(Java Server Pages) and XML technology.
Introduction to Java SE:
Java se is the general name of Java programming language and Java platform launched by Sun Microsystems in May 1995.
HotJava browser (supporting Java applets) implemented in Java shows the charm of Java: cross-platform, dynamic Web and Internet computing. Since then, Java has been widely accepted and promoted the rapid development of the Web, and now commonly used browsers support Java applet.
Java language is probably the first choice of network application language, which benefits from its high security and cross-platform characteristics. You can see Java on almost all computer platforms at present.
Java se is used to develop and deploy Java applications on desktops, servers, embedded devices and real-time environments. Java SE contains the class library for developing Java Web services, and Java SE provides the foundation for Java EE.
Features of Java Se:
Java is an object-oriented programming language;
Object-oriented is an idea of software development. It is an abstraction of the real world, and object-oriented will organize related data and methods into a whole.
Java abandons the concepts of multiple inheritance, pointer and memory management that are difficult to understand in C++. You don't have to manually manage the life cycle of an object.
The Java language has two characteristics: powerful and easy to use. Now enterprise-level development, rapid and agile development, especially the emergence of various frameworks, make Java become an increasingly popular language.
Java is a static language. Static language refers to a language that can know the data type at compile time, check the correctness of the type before running, and cannot be changed once the type is determined.
Java has platform independence and portability;
Java has a very famous slogan: write once and run everywhere, that is, write once and run everywhere.
Java can easily realize multithreading;
Java has high performance;
Java is robust;
Java is easy to develop distributed projects.
Introduction to JavaEE:
JavaEE applications are composed of components, that is, they are developed based on components. Components are units with independent functions, which are assembled into JavaEE applications through related classes and files, and interact with other components. The change of one component will not affect other components, so the code duplication is reduced and the reuse rate is high. Conducive to a good division of labor and cooperation, and achieve parallel development. If it is developed with a three-tier structure, the presentation layer and the data access layer are independent of each other, so the artist can expand the presentation layer more conveniently and make the system have good scalability.
JavaEE technical content:
JDBC:
Java data connection is a java API for executing SQL statements, which can provide unified access for various relational databases. With JDBC, you don't have to write different applications because of different databases. Developers only need to write a program using JDBC API.
JNDI:
Java naming and directory interface provides a unified way to find and access services on the network. It specifies a resource name, which corresponds to a record in the database or naming service, and returns the information necessary for the database to link resumes.
Restore multiple database links in the data source in advance and save them in the database connection pool. When a program accesses a database, it only needs to get idle database links from the connection pool. When the access ends, the resource is revoked and the database link returns to the connection pool.
EJB:
EJB is sun's javaEE server-side construction model. The design goal and core application is to deploy distributed applications. Simply put, it is to package the written program (that is, class) and put it on the server for execution. With the cross-platform advantage of java, the distributed system deployed by EJB technology can be independent of specific platforms. Including stateless reply bean (providing independent services), stateful reply bean (providing reply interaction), entity bean (reflecting persistent data in memory and recovering after server crash) and message-driven bean.
RMI:
Remote method call enables an object in a java virtual machine to call the method of an object in another java virtual machine like a local object.
JSP:
Java server page is a dynamic content template, which realizes Java extension with html syntax.
Servlet:
Servlet is a java applet, which extends the function of web server. As a server-side application, it starts executing at the same time as it is requested, similar to CGI Perl script. Most of the functions provided by servlets are similar to those provided by jsp, but they are implemented in different ways. Jsp usually embeds a small amount of java code in most html codes, while servlets are all written in java and merged into html.
XML:
Is an extensible markup language for sharing data in different business processes. Its goal is platform independence. Remember that when learning xml, you can write your own tags, as long as there is an end tag, you can recognize it. It's still quite powerful.
JMS:
Is an API about message middleware (MOM) on java platform, which is used to send messages between two applications or in a distributed system for asynchronous communication. Java message service is a platform-independent API, and most MOM providers support JMS. Message communication can be point-to-point or publish-subscribe type.
java IDL:
JavaIDL supports instantaneous CORBA objects, that is, it is valid during object server processing. In fact, the ORB of java IDL is only a class library, not a complete platform software, but it provides good communication support between java IDL application system and other CORBA application systems, and realizes the basic functions of ORB defined by OMG.
JTS:
Component transaction listener, TPM is a program that coordinates the execution of distributed things on behalf of applications. TPM and database appear almost at the same time; In the late 1960s, IBM first developed CICS, and people still use it today. Traditional (or programmed) TPM manages a series of operations that are programmed as transactional resources (such as databases). With the appearance of distributed object protocols such as CORBA, DCOM and RMI, people hope to see more prospects of object-oriented transactions. Informing object-oriented components of transaction semantics requires extending the TPM model-in this model, transactions are defined according to the calling methods of transaction objects, and JTS is just a component transaction monitor (sometimes called object transaction monitor) or CTM.
JTA:
JTA allows applications to perform distributed transactions, that is, access and update data on two or more network computer resources. JTA support of JDBC driver greatly enhances data access ability.
JavaMail:
Provides a programming interface for developers to handle e-mail.
JAF:
JAF is a special data processing framework, which is used to encapsulate data and provide an interface for applications to access and manipulate data.