什么是面向服务的架构？

Question

什么是面向服务的架构？

Answer 1

SOA is way to develop service oriented applications and WCF is technology which can be used to develop service oriented applications. BUT SOA defines strict rules (known as SOA tenets) for applications. If you don't follow these rules you are building services but these services do not conform to SOA.

WCF allows you to develop plenty of types of services. You can develop interoperable SOAP services which conform to SOA or which doesn't. You can develop pure .NET services with non interoperable features and you can develop REST services.

Moreover in SOA service can have different meaning than in WCF. In WCF service is collection of functionality exposed on endpoints. In SOA the service can be whole application (set of WCF like services) - difference between small and big SOA.

SOA tenets are:

• Boundaries are explicit - service doesn't share anything with other services (even database tables and data can't be shared)
• Services are autonomous - each service is independent, can be separately deployed and versioned
• Services share schema and contract, not class - services are described in WSDL, transported data are described in XSD, orchestrations (aggregation) are described in BPEL
• Services compatibility is based upon policy - WSDL contains WS-Policies to describe configuration needed for interoperability

As you see especially first two tenets can be easily violated when building WCF service.

Answer 2

SOA is a way to design a complete solution, it is a set of commonly accepted practices for communication, state management, compatibility, etc. In software architecture specifically, SOA is a set of services (not necessarily Web Services) that are built independently to support a range of client applications. The modular design helps maintenance, business collaboration. SOA also provides some guidelines for development:

• Constraints over backward compatibility
• Metadata exposure
• Discoverability of services

On the other hand, WCF is just a supporting technology that helps you build the services in .NET.

You can create a SOA without WCF, just as creating a bunch of WCF services does not make your architecture a service oriented one.

Answer 3

Service Oriented Architecture is a software architectural concept where one or more services interact with each other. Here, service means unit of work to accomplish a purpose. For an example, selling online ticket for railways is a service, online hotel booking is a service, procuring online payment is a service etc. Now, let's consider a hotel company sells its rooms online from its own website. In this case the website is using a local service. The same hotel can also sell rooms through a third party travel portal. In the second case the third party travel portal is using a remote service or web service. Selling hotel bookings online through a travel portal is an example of a Service Oriented Architecture . In service oriented architecture two or more parties interact with each other using web services. Among them few are web service providers and few are web service consumers. A software component can be built by following Service Oriented Architecture by using web services. WCF is a technology to build a service.

Answer 4

SOA is just a method through which we can interact between different technologies like in .NET and JAVA using Web Services. For this you have to be a knowledge in few things shown as follow.

1. XML
2. WSDL
3. UDDI
4. SOAP

after knowing these things you can easily apply this SOA

Answer 5

WCF是一种使构建服务更容易的技术，它不仅可以在所有传输上运行，因此它比仅适用于Http的Web服务更通用。