Java - J2EE Services 090826

 

J2EE Architecture

 

 

 

J2EE defines four types of component

ž            Application clients

ž            Applets

ž            Web components (Servlets and JavaServer Pages: provide the controller and view functionality in J2EE)

ž            Enterprise JavaBeans (Distributed, transactional components for business logic and database access)

 

 

 

J2EE defines four types of container

ž            Application client container (A stand-alone Java Runtime Environment)

ž            Applet container (Typically provided by a browser, possibly using the Java Plugin)

ž            Web component container (Provided by a J2EE application server)

ž            Enterprise bean (EJB) container (Provided by a J2EE application server)

 

 

 

Communication service in J2EE

 

Hypertext Transfer Protocol

The HTTP client-side API is defined by the java.net package.

The server-side API is defined by the Servlet and JSP interfaces.

 

RMI-IIOP

Remote method invocation(远程方法调用) over the internet inter-ORB protocol allows RMI-style programming independent of protocol.

 

Java IDL

Allows J2EE components to invoke external CORBA objects using IIOP, which may be written in any language.

 

 

JDBC 2.0 standard extension service in J2EE

JDBC is the API which provides vendor-independent connectivity to a variety of relational databases. The basic JDBC functionality is part of J2SE. The JDBC Core API is in the java.sql package. The Standard Extension is in the javax.sql package.

 

 

JTA service in J2EE

JTA (Java Transaction API Standard Extension) specifies interfaces between a transaction manager and the parties involved in a distributed transaction system.

Application developers will normally want to use container managed transaction demarcation, instead of using JTA.

 

 

Messaging service in J2EE

The Java Message Service (Java Messaging Service Standard Extension) is a standard, vendor-neutral API used to access enterprise message systems.

 

 

JavaMail service in J2EE

JavaMail Standard Extension and JAF is used to add e-mail capability to applications

 

 

JNDI service in J2EE

Java Naming and Directory Interface Standard Extension provides directory and naming functionality.

 

 

JAXP service in J2EE

Java API for XML Parsing enables applications to parse and transform XML documents.

 

 

J2EE Connector Architecture

Allows resource adapters that support access to Enterprise Information Systems (EIS) to be plugged into J2EE products

 

 

JAAS in J2EE

JAAS (Java Authentication and Authorization Service) can be used for two purposes:

ž            Authentication of users, to reliably and securely determine who is currently executing Java code, regardless of how the code is running.

ž            Authorization of users to ensure they have the permissions required to do the actions performed.