附录1 外文原文
Introducing the Spring Framework踏青英文
The Spring Framework: a popular open source application framework that address many of the issues outlined in this book. This chapter will introduce the basic ideas of Spring and dis-cuss the central “bean factory” lightweight Inversion-of-Control (IoC) container in detail.
Spring makes it particularly easy to implement lightweight, yet extensible, J2EE archi-tectures. It provides an out-of-the-box implementation of the fundamental architectural building blocks we recommend. Spring provides a consistent way of structuring your applications, and provides numerous middle tier features that can make J2EE development significantly easier and more flexible than in traditional approaches.
The basic motivations for Spring are:
To address areas not well rved by other frameworks. There are numerous good solutions to specific areas of J2EE infrastructure: web frameworks, persistence solutions, remoting to
ols, and so on. However, integrating the tools into a comprehensive architecture can involve significant effort, and can become a burden. Spring aims to provide an end-to-end solution, integrating spe-cialized frameworks into a coherent overall infrastructure. Spring also address some areas that other frameworks don’t. For example, few frameworks address generic transaction management, data access object implementation, and gluing all tho things together into an application, while still allowing for best-of-breed choice in each area. Hence we term Spring an application framework, rather than a web framework, IoC or AOP framework, or even middle tier framework. 毛姆传
To allow for easy adoption. A framework should be cleanly layered, allowing the u of indi-vidual features without imposing a whole world view on the application. Many Spring features, such as the JDBC abstraction layer or Hibernate integration, can be ud in a library style or as part of the Spring end-to-end solution.
To deliver ea of u. As we’ve noted, J2EE out of the box is relatively hard to u to solve many common problems. A good infrastructure framework should make simple task
s simple to achieve, without forcing tradeoffs for future complex requirements (like distributed transactions) on the application developer. It should allow developers to leverage J2EE rvices such as JTA where appropriate, but to avoid dependence on them in cas when they are unnecessarily complex.
To make it easier to apply best practices. Spring aims to reduce the cost of adhering to best practices such as programming to interfaces, rather than class, almost to zero. However, it leaves the choice of architectural style to the developer.
联通查话费号码Non-invasiveness. Application objects should have minimal dependence on the framework. If leveraging a specific Spring feature, an object should depend only on that particular feature, whether by implementing a callback interface or using the framework as a class library. IoC and AOP are the key enabling technologies for avoiding framework dependence.
Consistent configuration. A good infrastructure framework should keep application configuration flexible and consistent, avoiding the need for custom singletons and factorie
s. A single style should be applicable to all configuration needs, from the middle tier to web controllers.
Ea of testing. Testing either whole applications or individual application class in unit tests should be as easy as possible. Replacing resources or application objects with mock objects should be straightforward.
To allow for extensibility. Becau Spring is itlf bad on interfaces, rather than class, it is easy to extend or customize it. Many Spring components u strategy interfaces, allowing easy customization.
A Layered Application Framework
Chapter 6 introduced the Spring Framework as a lightweight container, competing with IoC containers such as PicoContainer. While the Spring lightweight container for JavaBeans is a core concept, this is just the foundation for a solution for all middleware layers.
多道程序Basic Building Blocks
元旦休息几天pring is a full-featured application framework that can be leveraged at many levels. It consists of multi-ple sub-frameworks that are fairly independent but still integrate cloly into a one-stop shop, if desired. The key areas are:
Bean factory. The Spring lightweight IoC container, capable of configuring and wiring up Java-Beans and most plain Java objects, removing the need for custom singletons and ad hoc configura-tion. Various out-of-the-box implementations include an XML-bad bean factory. The lightweight IoC container and its Dependency Injection capabilities will be the main focus of this chapter.
深圳合租记>深圳市宝安区Application context. A Spring application context extends the bean factory concept by adding support for message sources and resource loading, and providing hooks into existing environ-ments. Various out-of-the-box implementations include standalone application contexts and an XML-bad web application context.
巧克力海绵蛋糕
AOP framework. The Spring AOP framework provides AOP support for method interception on any class managed by a Spring lightweight container. It supports easy proxying of beans in a bean factory, amlessly weaving in interceptors and other advice at runtime. Chapter 8 dis-cuss the Spring AOP framework in detail. The main u of the Spring AOP framework is to provide declarative enterpri rvices for POJOs.
Auto-proxying. Spring provides a higher level of abstraction over the AOP framework and low-level rvices, which offers similar ea-of-u to within a J2EE context. In particular, the provision of declarative enterpri rvices can be driven by source-level metadata.
