【正文】 [9]: contract first and contract last. The difference between contract first and contract last approaches lies in whether the WSDL is created first or whether it is generated from code.Contract first approach is a good practice for developing Web services, when the service consumer and provider are external vendors who might implement the Web service using different technologies from each other (they may instead of Java)between Service and DAO) are configured in Spring application context files (). In a team environment these configuration files are shared by developers. That is why version conflicts on these configuration files might occur. The developed XYZ framework provides a new efficient approach that uses special annotations to specify all of these dependencies. By using these annotations, configurations bee simpler and conflicting changes to configuration artifacts are avoided.3. Services of the developed frameworkThe developed XYZ framework promotes the use of PlainOldJavaObjects (POJOs) to implement business logic. Business logic must be declared as interfaces. All service implementations must implement one or more business interfaces. It is remended that the service layer throws custom business exceptions when there are business rule validation errors. The developed XYZ framework adopts a declarative transaction management approach based on the Spring framework and finally we set up validation rules in .This approach has been changed in applications that were built using the developed XYZ framework, such that developers must not directly edit the or . Instead we specify this information as XDoclet annotations in the Action and ActionForm classes directly. This information is then transferred into the and by running the Ant script.There are two types of validations that are required: data format validation and business logic validation. Data format validations are best done in the presentation layer, while business logic validations are best done in the services layer. Business logic validation errors, which occur in the service layer, should be handled by throwing custom exceptions.The following are design goals for the presentation layer: (1) There is only one Action class ascending one ActionForm per JSP. A single Web page must all be handled in a single Action class. (2) Dependencies and validation rules are specified using XDoclet annotations. (3) Developers should avoid or minimize the use of session objects, because it hinders scalability.The XYZ framework provides a default template Action class that contains a solution to the above mentioned design goals for this layer. The following are typical code artifacts required for developing a Web page: (1) Create a new JSP with a default hidden field called “actionType” for use in handling user actions that are expected to occur on the page. (2) Create a new Action class that extends this template Action class. We must specify dependencies on ActionForm specific methods that handle user actions represented by values in hidden field “actionType”. After that we can declare permissions that are required in order to access this Action class. This is done in the Spring configuration files. (3) Create a new ActionForm class and specify validation rules as required using XDoclet annotations.Once the JSP, Action and ActionForm are created, it is necessary to run the Ant script to regenerate the “” file.. Database accessApplications built with the developed XYZ framework support the use of direct JDBC and Hibernate framework to persist in sending data to relational databases. The application is configured with the necessary Spring context files. DAOs that use direct JDBC must extend from Spring framework’s class. Similarly, DAOs that use Hibernate must extend from Spring framework’s class.. Configuration through annotationThe developed XYZ framework uses the Spring framework to maintain dependencies between code artifacts in applications. Some of these dependencies (. and also by enabling easy configuration of application to adapt to testing needs. Unit tests can be run like any JUnit test. The specially developed default “build script” provides a task to run unit tests. This task can be called when generating an EAR file for deployment or can be run separately.. Web presentation designThe developed XYZ framework uses the Struts framework concepts and JavaScript to implement presentation concerns and provides additional features that can be extended for use in projects. When using the Struts framework for development, at first we set up the Action Servlet in 。 (d) dependency management between all of the above. When starting development for a use case, we must be aware of the need of all these classes and their dependencies upfront.. Testing technologyTesting should be an integral part of the development process. For applications built using the developed XYZ framework, unit testing means testing methods of a single class in the service or integration layer. Presentation layer artifacts (Action classes) are not taken up for unit testing. The purpose of this test is to ensure that the behavior encapsulated by the class works as expected when testing integration with other ponents. Unit tests in applications, developed using the developed XYZ framework, are based on the JUnit framework (b) service interface and implementation class。 and (4) fully wired Spring application contexts can be run and tested entirely outside of the application server.The developed XYZ framework is configured by its application context. The application context may be defined in one or more XML files. A configuration set is a set of XML files that define one application context. The configuration set consists of two parts: service and Web. The service part defines services, DAOs, and resources for the service and integration layers. The Web part defines ponents for the presentation layer. A configuration set cannot