Java EE Overview (5)

Java EE application deployer and system administrators can be companies or individuals who configure and deploy the Java EE application, manage the low-level structures of the computers and networks in which the Java application is running, and monitor the running environment. Their tasks might include things like setting up transaction control, security properties, and specifying a database connection.

At configuration time, the deployer follows the instructions provided by the application component provider to resolve external support, specify security settings, and define transaction attributes. At installation time, the Deployer loads the application components into the server and generates the classes and interfaces for the specific container.

A Deployer/system administrator performs the following tasks to install and configure a Java EE application:

1. Add the Java EE application (EAR) file generated in the previous stage to the Java server
2, according to the operating environment by modifying the Java EE Application deployment instructions to the Java EE application configuration.
3, check the content of the ear file to comply with the Java code
4. Deploy (Install) Java EE application ear file to Java server

10, related to the implementation of the Software Java SDK is not operating the Java platform operation definition, it is provided by the sun can be free for demonstration, testing and educational purposes. It includes Java EE application servers, Web servers, relational databases, Java EE APIs, and a complete set of development and deployment tools. You can download the Java EE SDK from here:
Http://java.sun.com/j2ee/download.html#sdk

The purpose of the Java EE SDK is to allow product providers to test whether their execution requires a range of specific conditions and to run the Java compatibility Test to determine whether their Java EE products are fully compliant with the Java EE specification. The Java EE SDK can also be used by application component developers to run their Java EE applications to verify that they are fully suited to all of the Java EE products and tools.

10.1 Database access relational databases provide durable, robust storage for application data. A Java EE implementation does not need to support a particular type of database, which means that the databases supported by different Java EE products can be changed. See the download of the Java EE SDK contains a version of the description to understand the currently supported databases.

10.2 Java EE APIJ2SE SDK is necessary for the Java EE SDK to run, it can provide the core API, core development tools and Java Virtual machine for writing EE components. The Java EE SDK provides the following APIs for use by the Java EE application.

10.3 Enterprise JavaBeans Technology 2.0 A Enterprise bean is a code entity that has fields and methods for the module that executes the business logic. You can imagine a enterprise bean as a building block that can be used alone on the Java server or in conjunction with other enterprise beans to perform business logic.
There are three types of enterprise bean:session beans, Entity beans, and message-driven beans. Enterprise beans often have an interactive relationship with the database. One advantage of using entity beans is that you do not need to write any SQL code or use the JDBC API to perform database access operations directly; The EJB container handles these for you. However, if for some reason you overload the default container management persistence, you need to use the JDBC API. Similarly, if you select a session bean to access the database, you must also use the JDBC API.

The 10.4 JDBC API 2.0JDBC API allows you to invoke SQL commands from the Java programming language approach. In a enterprise bean, you must use the JDBC API when you overload the default container management persistence or access the database in a session bean. When using container management persistence, database access operations are handled by the container, and your enterprise bean executes without any JDBC code or SQL commands. You can also use the JDBC API to access the database directly from a servlet or JSP page, rather than through a enterprise bean.
The JDBC API has two parts: an application-level interface that is used by application components to access databases, and a service provider interface to integrate JDBC drivers into the Java EE platform.

The 10.5 Java servlet technology 2.3Java servlet technology allows you to define a specific HTTP servlet class. A servlet class extends a performance for the server: You can access the host application in a program mode such as request-response. Although the servlet can respond to any form of request, they are typically used for applications on the Web server.

10.6 JavaServer Pages Technology 1.2JavaServer pages enables you to embed servlet code into text-based documents. A JSP page is a text-based document that contains two types of text: static template data, which can be expressed as any text-based format, such as HTML, WML, and xml;jsp units, which determines how the page builds dynamic content.

The 10.7 Java Messaging Service (JMS) 1.0JMS is a message standard that allows Java EE applications to establish, send, receive, and read messages. It makes it possible to establish a connection between simple, reliable, and asynchronous, advertising-type communications. For more information about JMS, see the Java Messaging Service guide:
Http://java.sun.com/products/jms/tutorial/index.html

The 10.8 Java naming directory Interface (JNDI) 1.2JNDI provides named directory functionality. It provides a standard method of directory manipulation for an application, such as obtaining an object's associated properties, searching for objects based on their properties, and so on. Using Jndi, a Java-EE application can store and regain any type of named Java-based object.
Because Jndi does not depend on any particular execution, the application can access various named directory services using Jndi, including all existing named directory services such as LDAP, NDS, DNS, and NIS. This allows Java EE applications to coexist with traditional applications and systems. For more information about Jndi, refer to the Jndi guide:
Http://java.sun.com/products/jndi/tutorial/index.html

The 10.9 Java Transaction API 1.0Java transaction API (JTA) provides a standard interface for dividing transactions. The Java EE architecture provides a default autocommit to handle transaction commits and rollbacks. An autocommit means that when any other application displays data after each database read-write operation, it will see the updated data. However, if your application performs a two-part interdependent database access operation, you may want to use the JTA API to determine the entire transaction, which will contain the start, rollback, and submission of two operations.

10.10JavaMail API 1.2J2EE applications can use the JavaMail API to send e-mail notices. The JavaMail API consists of two parts: an application-level interface used by application components to send mail and a service provider interface. The Java EE platform contains the javamail provided as a service, enabling application components to send Internet mail.

10.11 JavaBeans Activate schema 1.0 to include the JavaBeans activation schema (JAF) because javamail to use it. It provides a standard service to determine the type of arbitrary data segment, how to access it, find the operations on which it can be applied, and establish the appropriate JavaBeans component to perform those operations.