JAX-WS2.0规范－－第一章：Introduction

Chapter1 IntroductionXML是一种平台无关的表示结构化信息的方式。XML Web服务使用XML为基础在基于网络的服务和这些服务的客户之间进行通信，并继承了XML的平台无关性。SOAP描述基于XML的消息格式，并“使用XML技术定义一个扩展的消息框架，该框架包含一个消息结构并能在各种潜在协议之间进行交换。”WSDL是“用XML格式将网络服务描述为一个操作面向文档或面向过程的信息的端点集合，”WSDL可以被视为XML Web服务实际上的描述语言。JAX-RPC1.0为在Java平台上支持面向RPC的XML Web服务定义了API和协议。JAX-RPC1.1增加了对WS-I Basic Profile1.0的支持以提高JAX-RPC执行器与使用其他技术实现的服务之间的互操作能力。JAX-WS2.0(当前这个规范)是JAX-RPC1.1的后续，并对其做了以下扩展：1.1    目标自从JAX-RPC 1.0的发布以来，它所依赖的新的规范以及标准的新版本也随着发布了。就像下面所说的，JAX-WS2.0就是跟这些规范跟标准有关：JAXB由于最初时间上的关系，JAX-RPC 1.0定义了它自己的数据绑定策略。随着JAXB 1.0的发布。没有理由在Java平台上要维护两种独立的XML映射规则集合。JAX-WS 2.0将会把数据绑定相关的任务委派给JAXB 2.0规范，它是跟JAX-WS 2.0同时被开发的。      JAXB 2.0将会增加对Java到XML映射的支持，另外也支持少使用XML　schema结构，并且提供了Java<-->XML数据绑定的双向的自定义。JAX-WS 2.0将允许完全使用JAXB所提供的包括绑定自定义和可选的schema验证的功能。SOAP 1.2 在SOAP 1.1在还被大范围使用的同时，既然是作为W3C所推荐的，我们可以期待服务将要移植到SOAP1.2。当需要继续支持SOAP 1.1的同时，JAX-WS2.0将支持SOAP 1.2.WSDL 2.0 在这个JSR存在期间，W3C希望加快WSDL 2.0的推荐方案。WS-I Basic Profile 1.1 JAX-RPC 1.1增加了对WS-I Basic Profile 1.0的支持。WS-I Basic Profile 1.1 是希望在这个JSR还存在的时候将会取代1.0并且JAX-WS 2.0将会增加它所提供的附加的解释的支持。Java编程语言的元数据功能（JSR 175）JAX-WS2.0将会定义Java注释的使用来简化客户端和服务器端那些比较常用的开发场景。基于Java平台的Web服务元数据(JSP 109)JSR109 定义了jaxrpc-maping-info配置描述符提供了部署运行时Java与WSDL之间的映射功能。跟JSR 181关联一起，JAX-WS 2.0使用控制Java跟WSDL之间映射的运行时Java注释将会实现这种映射功能。Web服务安全(JSR183) JAX-WS 2.0 将会和JSR(183)定义的安全API保持一致并实现它。JAX-WS 2.0将会改善以文挡/消息为中心的使用：异步性（Asynchrony）JAX-WS 2.0将会增加对客户端异步操作的支持。
非-HTTP传输（Non-HTTP Transports）JAX-WS 2.0将会改善XML消息格式跟底层传输机制来简化基于非-HTTP传输时JAX-WS使用。
消息访问 JAX-WS2.0 将会简化客户端和服务端交换下的消息访问。
会话管理 JAX-RPC 1.1会话管理能力被绑在了Http之上。JAX-WS 2.0 将会增加对基于消息的会话管理。]JAX-WS 2.0 也将会提出那些随着实现和使用JAX-RPC1.0的经验而出现的问题：包含在J2SE　JAX-WS2.0 将会为JAX-WS准备包含在将来的J2SE的版本。应用的可移植性是一个关键的需求而且JAX-WS2.0 将会定义机制来产生完全具有可移植性的客户端非-HTTP传输。 HandlersJAX-WS 2.0 将会简化handlers的开发并且会提供一种机制来允许handlers跟服务客户端还有服务端点的实现的协作。
Versioning and Evolution ofWeb Services JAX-WS 2.0 will describe techniques and mechanisms to ease　the burden on developers when creating new versions of existing services.
1.2 非目标
The following are non-goals:
Backwards Compatibility of Binary Artifacts Binary compatibility between JAX-RPC 1.x and JAX-WS　2.0 implementation runtimes.
Pluggable data binding JAX-WS 2.0 will defer data binding to JAXB[10]; it is not a goal to provide a plug-in API to allow other types of data binding technologies to be used in place of JAXB. However,
JAX-WS 2.0 will maintain the capability to selectively disable data binding to provide an XML based fragment suitable for use as input to alternative data binding technologies.
SOAP Encoding Support Use of the SOAP encoding is essentially deprecated in the web services community,
e.g., the WS-I Basic Profile[8] excludes SOAP encoding. Instead, literal usage is preferred,
either in the RPC or document style.
SOAP 1.1 encoding is supported in JAX-RPC 1.0 and 1.1 but its support in JAX-WS 2.0 runs counter
to the goal of delegation of data binding to JAXB. Therefore JAX-WS 2.0 will make support for SOAP 1.1 encoding optional and defer description of it to JAX-RPC 1.1.
Support for the SOAP 1.2 Encoding[4] is optional in SOAP 1.2 and JAX-WS 2.0 will not add support for SOAP 1.2 encoding.
Backwards Compatibility of Generated Artifacts JAX-RPC 1.0 and JAXB 1.0 bind XML to Java in different
ways. Generating source code that works with unmodified JAX-RPC 1.x client source code is
not a goal.
Support for Java versions prior to J2SE 5.0 JAX-WS 2.0 relies on many of the Java language features added in J2SE 5.0. It is not a goal to support JAX-WS 2.0 on Java versions prior to J2SE 5.0.
Service Registration and Discovery It is not a goal of JAX-WS 2.0 to describe registration and discovery
of services via UDDI or ebXML RR. This capability is provided independently by JAXR[16].
 plug-in API to allow other types of data binding technologies to be used in place of JAXB. However,
JAX-WS 2.0 will maintain the capability to selectively disable data binding to provide an XML based
fragment suitable for use as input to alternative data binding technologies.
SOAP Encoding Support Use of the SOAP encoding is essentially deprecated in the web services community,
e.g., the WS-I Basic Profile[8] excludes SOAP encoding. Instead, literal usage is preferred,
either in the RPC or document style.
SOAP 1.1 encoding is supported in JAX-RPC 1.0 and 1.1 but its support in JAX-WS 2.0 runs counter
to the goal of delegation of data binding to JAXB. Therefore JAX-WS 2.0 will make support for SOAP
1.1 encoding optional and defer description of it to JAX-RPC 1.1.
Support for the SOAP 1.2 Encoding[4] is optional in SOAP 1.2 and JAX-WS 2.0 will not add support
for SOAP 1.2 encoding.
Backwards Compatibility of Generated Artifacts JAX-RPC 1.0 and JAXB 1.0 bind XML to Java in different ways. Generating source code that works with unmodified JAX-RPC 1.x client source code is not a goal.
Support for Java versions prior to J2SE 5.0 JAX-WS 2.0 relies on many of the Java language features added in J2SE 5.0. It is not a goal to support JAX-WS 2.0 on Java versions prior to J2SE 5.0.
Service Registration and Discovery It is not a goal of JAX-WS 2.0 to describe registration and discovery of services via UDDI or ebXML RR. This capability is provided independently by JAXR[16].