EndPoints （端点）

在WSDL中，服务作为网络的端点，或者端口。WSDL中的端点和消息的抽象定义独立与绑定时其实际的网络部署或数据形式。因此可重用抽象的定义：消息是交换数据的抽象描述，端口类型是操作的抽象集合。

A WSDL document defines services as collections of network endpoints, or ports. In WSDL, the abstract definition of endpoints and messages is separated from their concrete network deployment or data form at bindings. This allows the reuse of abstract definitions: messages,which are abstract descriptions of the data being exchanged, and port types which are abstract collections of operations.The concrete protocol and data format specifications for a particular port type constitutes a reusable binding.A port is defined by associating a network address with are usable binding, and a collection of ports define a service.Hence, a WSDL document uses the following elements in the definition of network services:

• Types– a container for data type definitions using some type system (such as XSD). 类型
  
• Message– an abstract, typed definition of the data being communicated. 消息
  
• Operation– an abstract description of an action supported by the service. 操作
  
• Port Type–an abstract set of operations supported by one or more endpoints. 端口类型
  
• Binding– a concrete protocol and data format specification for a particular port type. 绑定
  
• Port– a single endpoint defined as a combination of a binding and a network address. 端口
  
• Service– a collection of related endpoints. 服务。
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