Application of SOA Structure Model in enterprise information integration

1. Traditional Methods for enterprise information integration Analysis

Enterprise Application Integration (ea I: enterp rise application integration)
It refers to the integration of application systems for enterprises to complete different business functions, and the establishment of a link between them for data exchange and application communication,
In this way, information interaction between them becomes possible. In this way, users can access the overall information of an enterprise, without having to consider which application system the specific information belongs,
That is, different application systems are transparent to users.

Traditional Enterprise Application Integration Layers include data-level integration, application interface-level integration, and business logic-level integration. Data-level integration is an information-oriented integration method,
This method may cause damage to data and open the security gap of the database. Application Interface-level integration is an interface-oriented integration method. When this method is used to modify the ap I interface,
This will increase the workload and may increase the instability of existing application systems. Business logic-level integration is a process-oriented integration method. This integration method not only exposes the business logic of the application,
In addition, the intersection of business logic leads to tight coupling between various integrated systems, reduces the flexibility of application systems, and increases the difficulty of system maintenance.

The above three methods are tightly coupled application system integration methods. This tightly coupled Integration Method affects system flexibility and scalability, and hinders business process adjustment and optimization,
This is not conducive to the business development of enterprises. To solve these problems, a function-oriented enterprise system integration method is required. This method not only ensures the data security and logic security of the original system,
In addition, the system can be loosely coupled to facilitate system flow reorganization and optimization. The emergence of SOA provides a perfect solution for this problem.

2. Service-Oriented Architecture (SOA ):

2.1 Introduction to service-oriented architecture

SOA (service-oriented
Architecture, also known as service-oriented architecture or service-oriented architecture) refers to the independence that can complete specific tasks through connection to meet the needs of business integration in the Internet environment.
A software system architecture implemented by functional entities. SOA is a component model that associates different functional units (called services) of an application with well-defined interfaces and contracts between these services. Interface is
It is defined in a neutral way. It should be independent of the hardware platform, operating system, and programming language that implements the service. This allows services built in various such systems to be handed over in a unified and universal manner.
Mutual.

The traditional Web (html/HTTP) technology effectively solves the problem of interaction and communication between people and information systems, and greatly promotes the development of B2C mode. Web Service (XML
/Soap/WSDL) technology is to effectively solve the interaction and communication problems between information systems and promote the development of B2B, EAI, and cb2c. SOA (a service-oriented system) adopts
The commercial modeling technology and Web Service technology of services can achieve loose coupling between systems and integration and collaboration between systems. The fundamental idea of Web Services and SOA lies in the ability of individual information systems to communicate.
To form collaborative work.

2.2 SOA Structure Model

SOA provides a way to build a distributed system,
Application functions can be provided as services to end-user applications or other services. With the expectation of discovering new business opportunities or crises, the SOA architecture is designed to provide enterprise business solutions,
These business solutions can be expanded or changed as needed. An SOA solution consists of reusable services with well-defined and compliant released interfaces. SOA provides a mechanism,
Through this mechanism, the original system resources can be encapsulated into services and then integrated into the newly developed distributed system,
Regardless of their platform or language. Services in SOA interact with each other through service description and transmission, as shown in 1.

　　

The service description is a negotiated model used to describe what the service is, how the service should be called, and what data is required to successfully call the service. Transmission is a mechanism used to send service requests from service users to service providers and send responses from service providers to services.

2.3 roles in SOA

In the SOA service model diagram (Figure 2), there are three main roles in the service-oriented architecture:

　　

(1) A service consumer is an application or other service that needs to use the service. After querying the services in the Registration Center, describe the information based on the interface and use a certain transmission protocol to bind the service and execute the service functions.

(2) a service provider is the entity for creating a service. You can receive requests from the service consumer and remotely execute the requested service. Publish service interface information to the Registration Center for service consumers to discover and access the service.

(3) The service registration center is in the center and provides the function of displaying the service. The service consumer queries the Registration Center that stores the service information library to find the interface information of the service that is interested in.

2.4 three basic features of SOA

1. independent functional entities
: In a loose environment like the Internet, any access request may go wrong. Therefore, any structure that attempts to control over the internet will face serious stability problems.
SOA emphasizes the completely independent capabilities of functional entities that provide services in the architecture. Traditional component technologies such as. net
Remoting, EJB, COM, or CORBA all require a host (host or server) to store and manage these functional entities. When these hosts end, these groups
The service life of the component also ends. In this way, other application services running on the host will be affected when the host itself or other functions are faulty.

The SOA architecture emphasizes entity self-management and recovery capabilities. Common technologies used for self-recovery, such as transaction and Message Queue
Message Queue, redundant deployment, and cluster play a crucial role in SOA.

Ii. Low-frequency access to large data volumes: For. net
Remoting, EJB or XML-RPC traditional distributed computing models, their service is provided through the function call method, a function is often completed through the customer
Function calls can be performed multiple times between the user and the server. In an Intranet environment, the impact of these calls on the system's response speed and stability is negligible.
In the Internet environment, these factors are often a key factor that determines whether the entire system can work normally. Therefore, it is recommended that the SOA system exchange information with large data volumes at one time.

III,
Text-based message transmission: due to the existence of a large number of heterogeneous systems in the Internet, SOA must adopt text-based instead of binary message transmission methods. In the COM, CORBA
In the traditional component model, a binary-encoded object is uploaded from the server to the client. The client calls the method of this object to complete some functions. However, in the Internet environment
Different platforms have different definitions of data and even some basic data types, which makes it very difficult to transmit objects between different services. Because text-based messages do not contain any processing logic or data classes
Therefore, only text is transmitted between services. Data Processing relies on the acceptor to help bypass the compatibility challenge.

In addition, for a service, the biggest difference between the Internet and LAN is that version management on the internet is extremely difficult.
In a loose distributed environment, it is almost impossible. In the text-based message transmission mode, the data processing end can only selectively process the part of the data that you understand, and ignore other data.
Expected compatibility.

It can be seen from several important characteristics of SOA that SOA is used for information resource integration because it has the features of standardization, operation and assembly. SOA provides a common
Interoperable and elastic industry-standard architecture, a series of reusable services supporting business models can be established in the software infrastructure. These services are composed of components of different application systems, can help enterprises achieve
Adapt to business process changes.

Iii. Enterprise Information System Integration Using SOA

3.1 steps for integrating existing enterprise information systems with SOA:

1) extract the functional modules that need to be exposed in each application system. These functional modules are usually software entities that clearly and completely express their business values. The software entity contains all the services it can provide.

2) present these functional modules as service components. Define the service description, service interfaces, and positioning information required to call the service. Converts a conceptual model of a software entity to an actual service model.

3) Publish the implemented service to the service registrar for other service callers to search and bind it. This step can be selected based on the specific situation of enterprise integration.

4) bind and call services, and integrate various application systems to achieve functional integration of enterprise applications (see figure 3 ).

　　

3.2 Implementation Suggestions

"Integration is implemented in stages, step by step, and step by step. If all business activities of an enterprise are regarded as services, integration means to organically link various internal and external services of the enterprise. First
You can first create a separate service. Next, you can not only create a service, but also start to integrate business functions into SOA. Step 3 involves converting the enterprise IT infrastructure to the SOA model; last concentrated
To transform the business model to adapt to changes in requirements.

For specific integration objects, integration is implemented in four stages: Modeling, assembly, deployment, and management. In the modeling phase, you can define business models or processes, software models, and SOA models. Then you can create
A group of services that can be reused with released universal interfaces. in the deployment phase, developers can extract the created services, and put them in an executable and manageable environment; In the use phase,
Assemble an application according to the software model and test its software quality and non-functional requirements, such as performance and scalability. The final management stage is a long-term process. In this stage, can be monitored and
Manage Security and use, and compare performance in many aspects that may correspond to service-level agreements or policies that have been developed for SOA.

In this way, small and large enterprises gradually integrate and expand their businesses, form an IT transformation for the entire enterprise, and finally implement an on-demand enterprise IT architecture through comprehensive integration.

3.3 SOA enterprise information system integration based on Web Service Architecture

As a concept, SOA has matured. In comparison, the current Web service is the best way to implement SOA. The Web Service is composed
Resource Locator) determines the software application, its interface and binding can be XML (extensiblemarkup LANGUAGE)
Format definition, description, and discovery, and supports Internet protocol, such as soap (simple objectaccess Protocol)
. Use XML format messages to interact with other software applications. Web services use [6] WSDL (Web servicesdescrip tion
Language ),
Integration) Protocol Specification for online registration of web services and service Search and positioning, and use the soap transmission protocol to interact information in XML format between networks.

XML is an Extended Markup Language. The Web Service Description Language is described in XML format, and the Web service data is also exchanged in XML format. XML is the cornerstone for defining web service protocol specifications.

The WSDL Service Description Language is defined in XML schema. WSDL can describe services implemented in various languages and has language independence.

Dd I is a common description, discovery, and integration protocol. Udd I makes it possible to globally locate and discover services.

3.4 web service integration Implementation Model

To run and manage SOA applications, enterprises need an SOA integration model, which is part of the SOA platform. The SOA integration model must support all relevant standards and required runtime containers. Figure 4 shows a typical SOA integration model. The following sections describe these layers respectively.

　　

SOAP, WSDL, and UDDI
: WSDL, UDDI, and soap are basic components of SOA. WSDL is used to describe the service; UDDI is used to register and search for the service; and soap is used as the transport layer
Send messages between service providers. Soap is the default mechanism of Web Services. Other technologies enable binding of other types of services. A consumer can log on to the UDDI registry)
Search for the service, obtain the WSDL description of the service, and then call the service through soap.

WS-I basic profile: S-I basic profile, organized by Web Services
Interoperability organization) is a core component required for SOA service testing and interoperability. Service providers can use basic
Profile testing programs are used to test service interoperability on different platforms and technologies.

J2EE and. net
: Despite J2EE and. NET platform is a common platform for developing SOA applications, but SOA is not limited to this. Platforms such as J2EE not only provide developers with natural PARTICIPATION IN SOA
A platform also introduces scalability, reliability, availability, and performance to the SOA world through its internal features. New specifications, such as jaxb (Java API for XML
Binding), used to locate the XML document to the Java class; jaxr (Java API for XML
Registry) is used to regulate the operation of the UDDI registry (Registry); XML-RPC (Java API for XML-based
Remote Procedure
Call) is used to call remote services in j2ee1.4, which makes it easy to develop and deploy Web services that can be transplanted to standard J2EE containers. At the same time, cross-platform (such. Net)
Services.

Service quality: in an enterprise
System: if the reliability of a system is critical to an organization, the system is the key task system of the enterprise. For example, the telephone system
A promotion enterprise is a key task system, and a text processing system is not that critical .) It is used to address advanced requirements, such as security, reliability, and transactions. When an enterprise begins to use the service architecture as a tool
Basic Web service specifications, such as WSDL, soap, and UDDI, cannot meet these advanced requirements when developing and deploying applications. As mentioned above, these requirements are also called service quality.
(QoS, quality of services ). QoS-related specifications have been standardized by some organizations
Bodies, such as W3C (World Wide Web Consortium) and OASIS (the Organization
The Advancement of Structured Information
Standards ). The following sections will discuss some QoS services and related standards.

Security: Web service security specifications are used to ensure message security. This specification mainly includes authentication exchange,
Message integrity and confidentiality. This specification is attractive because it leverages existing security standards, such as SAML (as Security Assertion Markup
Language) to secure Web service messages. Oasis is working on developing Web service security specifications.

Reliability: in a typical SOA environment, there are several different documents between service consumers and service providers for exchange. Such as "Send only once "(
Once-and-only-Once delivery), "At-most-once"
Delivery), duplicate message elimination, and guaranteed
Message delivery ).
Systems) becomes very important. WS-reliability and
WS-reliablemessaging is two criteria for solving such problems. Oasis is currently responsible for these standards.

Policy
: Service Providers sometimes require service consumers to communicate with certain policies. For example, a service provider may require consumers to provide Kerberos Security labels to obtain a service. These requirements are defined
Policy assertions ). A policy may contain multiple assertions. WS-policy is used to standardize the policy communication between service consumers and service providers.

Control: When an enterprise is working on a service architecture, the service can be used to integrate the silos
Data), applications, and components. Integrated Applications mean that process requests such as Asynchronous Communication, parallel processing, data conversion, and correction must be standardized. In SOA, a process uses a discrete set
Service created. BPEL4WS or wsbpel (Web Service Business Process execution)
Language) is the language used to control these services. Wsbpel is also under the responsibility of oasis.

Management
: As Enterprise Services grow, the number of services used and business processes also increases, it is particularly important that a system administrator manage all services running in a multi-phase environment.
Wsdm (Web Services for distributed
Management) specifies that any service implemented according to wsdm can be managed by a Management Solution of wsdm-compliant.

Other QoS features, such as communication and communication between partners and transaction processing between multiple services, are described in the WS-coordination and WS-Transaction Standards, these are all oasis jobs.

Iv. Conclusion:

SOA provides a standardized architecture. services corresponding to an application can also be applied to other applications. The speed of developing new applications will be greatly improved, and old systems can also be packaged as services, services can be combined to meet the needs of new businesses, so as to integrate information system resources.