【導讀】聯(lián)系Q709604208獲取。目錄。聯(lián)系Q709604208獲取

　　

【正文】 of its modules is delivered in an Enterprise ARchive (EAR) file. An EAR file is a standard JAR file with an .ear extension. In the GUI version of the J2EE SDK application deployment tool, you create an EAR file first and add JAR and WAR files to the EAR. If you use the mand line packager tools, however, you create the Java ARchive (JARs) and Web ARchive (WAR) files first and create the EAR. The J2EE SDK tools are described in Tools. Each EJB JAR file contains its deployment descriptor, related files, and the .class files for the enterprise bean. Each application client JAR file contains its deployment descriptor, related files, and the .class files for the application client. Each WAR file contains its deployment descriptor, related files, and the .class files for the servlet or .jsp files for a JSP page. Using modules and EAR files makes it possible to assemble a number of different J2EE applications using some of the same ponents. No extra coding is needed。 it is just a matter of assembling various J2EE modules into J2EE EAR files. Chapter 4 Development Roles Reusable modules make it possible to divide the application development and deployment process into distinct roles so different people or panies can perform different parts of the process. The first two roles involve purchasing and installing the J2EE product and tools. Once software is purchased and installed, J2EE ponents can be developed by application ponent providers, assembled by application assemblers, and deployed by application deployers. In a large anization, each of these roles might be executed by different individuals or teams. This division of labor works because each of the earlier roles outputs a portable file that is the input for a subsequent role. For example, in the application ponent development phase, an enterprise bean software developer 聯(lián)系 Q709604208 獲取 delivers EJB JAR files. In the application assembly role, another developer bines these EJB JAR files into a J2EE application and saves it in an EAR file. In the application deployment role, a system administrator at the customer site uses the EAR file to install the J2EE application into a J2EE server. The different roles are not always executed by different people. If you work for a small pany, for example, or if you are prototyping a sample application, you might perform the tasks in every phase. J2EE Product Provider The J2EE product provider is the pany that designs and makes available for purchase the J2EE platform, APIs, and other features defined in the J2EE specification. Product providers are typically operating system, database system, application server, or web server vendors who implement the J2EE platform according to the Java 2 Platform, Enterprise Edition Specification. Tool Provider The tool provider is the person or pany who makes development, assembly, and packaging tools used by ponent providers, assemblers, and deployers. See Tools for information on the tools available with J2EE SDK version . Application Component Provider The application ponent provider is the pany or person who creates web ponents, enterprise beans, applets, or application clients for use in J2EE applications. Enterprise Bean Creation A software developer performs the following tasks to deliver an EJB JAR file that contains the enterprise bean: Writes and piles the source code Specifies the deployment descriptor Bundles the .class files and deployment descriptor into an EJB JAR file Web Component Creation 聯(lián)系 Q709604208 獲取 A web designer (JSP pages) or software developer (servlets) performs the following tasks to deliver a WAR file containing the web ponent. Writes and piles servlet source code Writes JSP and HTML files Specifies the deployment descriptor for the web ponent Bundles the .class, .jsp, .html, and deployment descriptor files in the WAR file J2EE Application Client Creation A software developer performs the following tasks to deliver a JAR file containing the J2EE application client. Writes and piles the source code Specifies the deployment descriptor for the client Bundles the .class files and deployment descriptor into the JAR file Application Assembler The application assembler is the pany or person who gets application ponent JAR files from ponent providers and assembles them into a J2EE application EAR file. The assembler or deployer can edit the deployment descriptor directly or use tools that correctly add XML tags according to interactive selections. A software developer performs the following tasks to deliver an EAR file containing the J2EE application. Assembles EJB JAR and web ponents (WAR) files created in the previous phases into a J2EE application (EAR) file. Specifies the deployment descriptor for the J2EE application. Verifies that the contents of the EAR file are wellformed and ply with the J2EE specification. Application Deployer and Administrator The deployer and administrator is the pany or person who configures and deploys the J2EE application, administers the puting and working infrastructure where J2EE applications run, and oversees the runtime environment. Duties include such things as setting transaction controls, security attributes, and specifying connections to databases. During configuration, the deployer follows instructions supplied by the application ponent provider to resolve external dependencies, specify 聯(lián)系 Q709604208 獲取 security settings, and assign transaction attributes. During installation, the deployer moves the application ponents to the server, and generates the containerspecific classes and interfaces. A deployer/system administrator performs the following tasks to install and configure a