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1、SOA & BPEL: Building a Service With BPEL and the Java EE Platform,Agenda,This session describes how developers using Java Platform, Enterprise Edition can create composite applications using BPEL with current Java EE tools and application servers that support Java Business Integration,Agenda,Why Ser
2、vices Why Composite Applications BPEL in the Mix A Java EE Based Composite Application Summary,Why Services?,SOA = an architectural principle for structuring systems that SOA emphasizes the de-coupling of system components New services are created from existing ones in a synergistic fashion Strong s
3、ervice definitions are critical Services can be subsequently re-composed in response to changing business requirements,What Are Services?,A function accessed using XML message exchange Message exchanges have well known exchange patterns Services are self-describing, usingmetadata (WSDL),What Does a
4、Service Do?,Transform data Route messages Query databases Orchestrate conversations Apply business logic Apply business policy Handle business exceptions Solicit approvals ,How Is a Service Implemented?, XSLT Enterprise JavaBeans (EJB) technology BPEL SQL XQuery Routing table Business rules EDI tran
5、sform ,Service Oriented Architecture,In April 2006 the Object Management Groups (OMG) SOA Special Interest Group adopted the following definition for SOA Service Oriented Architecture is an architectural style for a Community of providers and consumers of services to achieve mutual value, that Allow
6、s participants in the communities to work together with minimal co-dependence or technology dependence Specifies the contracts to which organizations, people and technologies must adhere in order to participate in the community Provides for business value and business processes to be realized by the
7、 community Allows for a variety of technologies to be used to facilitate interactions within the community,Service Oriented Architecture,In March 2006 the OASIS group SOA Reference Model released its first public review draft. This defines the basic principles of SOA that apply at all levels of a se
8、rvice architecture, from business vision through to technical and infrastructure implementation Service Oriented Architecture; a paradigm for organizing and utilizing distributed capabilities that may be under the control of different ownership domains. It provides a uniform means to offer, discover
9、, interact with and use capabilities to produce desired effects consistent with measurable preconditions and expectations,Principles of SOA,Services share a formal contract Services are loosely coupled Services abstract underlying logic Services are composable Services are reusable Services are auto
10、nomous Services are stateless Services are discoverable,Benefits of SOA,Flexible (Agile) IT Adaptable to changing business needs Faster time to market Reuse existing code, minimize new development Business and process-driven New business opportunities Greater ROI Leverage existing IT asset,Composite
11、 Applications,Composite applications are.applications! Comprised of heterogeneous parts Some existing parts Some new parts Composite applications != SOA Composite applications employ SOA principles Features exposed as Web services Standards-based interaction between services Described by standards-b
12、ased artifacts Are themselves composable,Purchase Service,Purchase Service Functions,Composite ApplicationsSummary,A composite application is a collection of existing and independently developed applications and new business logic, orchestrated together into a brand new solution of a business proble
13、m that none alone can solve Such an application looks to the user like a regular new interactive application, yet in reality it may be only 10 percent new and 90 percent an assembly of pre-existing components or data; The “glue” that brings a composite application together is integration technology,
14、WS-BPEL Works With WSDL Web Services Business Process Execution Language,Web services are described in WSDL Operations are message exchanges Each operation represents an individual unit of action We need a way to orchestrate these operations with multiple web services in the right order to perform a
15、 Business process Sequencing, conditional behavior etc. BPEL provides standard-based orchestration of these operations,What is BPEL?,XML-based language used to specify business processes based on Web Services BPEL processes describe Long running, stateful, transactional, conversations between two or
16、 more partner web services BPEL is key to implementing SOA Big Rules Conversational Mostly Async XML Document-based Orchestrated,BPEL Is a Web Service Sequencing Language,Process defines “conversation” flow chart Conversation consists of only WSDL-described message exchanges BPEL provides and consumes WSDL defined services Process instance is a particular conversation following the chart Execution systems can support multiple concurrent conversations,BPEL “Fixes” WSDL,WSD
