基于CORBA和Web Services集成技术的研究与实现
摘要
Web Services和以CORBA为代表的分布式对象技术是当前两大研究和发展的热点。Web Services为用户提供了友好、方便的使用界面，并屏蔽异构的操作系统、网络和编程语言，而且屏蔽了传统中间件之间的异构性，并支持开放、动态的互操作模式。但其无法胜任大规模的企业计算和服务。其主要问题在于系统需要HTTP和Web服务器作为中介，这必然在Web服务器处形成瓶颈，造成响应速度减慢。CORBA提供了在异构平台上构造对程序开发人员透明的分布式环境，它利用面向对象、软件总线和部件等技术，为异构、分布式系统提供了系统集成功能，具有跨语言、跨平台、结构规范、可移植、实施灵活等巨大优势。但CORBA在穿越防火墙时遇到困难，二进制与现有Internet编码标准不统一，更主要的是开放节点可能采用不同的中间件实现，导致基于传统中间件的系统难以跨越Internet进行动态交互。
CORBA和Web Services应用集成的方式主要有两种：一种是Web Services客户端访问CORBA服务器，另一种是CORBA客户端访问Web Services服务器。因为应用集成通常通过封装已用或开发程序对外提供服务，所以文本讨论的集成技术主要是第一种，即Web Services客户端访问CORBA服务器。
本文对CORBA和Web Services技术进行了介绍和对比，并对现有的CORBA与WebServices集成方案的研究的基础上，提出并实现了一种新的Web Services和CORBA的集成方案，即采用SOAP／IIOP网关协议转化技术，仅仅使用Web页面就可以完成对CORBA对象的访问和调用，而对客户端没有任何附加的要求。SOAP／IIOP网关技术与现有的CORBA和Web Services集成方案比较：一方面简化了基于Web Services的CORBA应用程序的开发，实现了复杂的服务；另一方面也提高了服务对Web请求的响应速度。最后把我们把SOAP／IIOP网关技术应用到了远程变电站监控。
Web Services and CORBA distributed object technology are the issues of research and development.Web Services provides users with a friendly, convenient user interface, it also shields heterogeneous of operating systems, network and programming languages, different middleware, supports an open , dynamic interoperability model.But Web services is no longer meet to the large-scale enterprise computing and services. The main problem is that system needs HTTP and Web server as an intermediary. This is bound to create the bottleneck in the Web server, resulting in a slower rate of response. CORBA provides a distributed environment in heterogeneous platforms, which is transparent to the development staff of the procedure in structure. It provides heterogeneous, distributed system with a system integration functions, using object-oriented software components and bus technology. It has great advantages of cross-language, cross-platform, standardized structure, portable, flexible.But CORBA has difficulties in crossing the firewall, because the binary coding cannot unify with the existing Internet standard. More importantly, open nodes may have a different middleware, leading that the systems based on traditional middleware can hardly dynamic interaction through the Internet.
Integration of Web and CORBA are mainly two ways , one is the Web Services, clients access to CORBA server, the other integrated way is CORBA clients visit Web Services server. Because integration is applied normally through encapsulating exsiting procedures or developing new procedures to provide services. Therefore, this article mainly discussed first integration technology, Web Services Client access to CORBA Server.
Based on the existing CORBA and Web Services integration, We proposed and implemented a new Web Services and CORBA integration program based on SOAP/IIOP protocol conversion technologies. Web pages can be used only to fulfill the access and visit of CORBA object, without any additional requirements to clients. Compared with existing CORBA and Web Services program, SOAP/IIOP program has two advantages:First, it simplifies the application procedures for the development and the services;Second, it improves the response speed of the service request to the Web.Finally SOAP/IIOP gateway is applied to the remote substation monitoring .
CORBA和Web Services应用集成的方式主要有两种：一种是Web Services客户端访问CORBA服务器，另一种是CORBA客户端访问Web Services服务器。因为应用集成通常通过封装已用或开发程序对外提供服务，所以文本讨论的集成技术主要是第一种，即Web Services客户端访问CORBA服务器。
本文对CORBA和Web Services技术进行了介绍和对比，并对现有的CORBA与WebServices集成方案的研究的基础上，提出并实现了一种新的Web Services和CORBA的集成方案，即采用SOAP／IIOP网关协议转化技术，仅仅使用Web页面就可以完成对CORBA对象的访问和调用，而对客户端没有任何附加的要求。SOAP／IIOP网关技术与现有的CORBA和Web Services集成方案比较：一方面简化了基于Web Services的CORBA应用程序的开发，实现了复杂的服务；另一方面也提高了服务对Web请求的响应速度。最后把我们把SOAP／IIOP网关技术应用到了远程变电站监控。
Web Services and CORBA distributed object technology are the issues of research and development.Web Services provides users with a friendly, convenient user interface, it also shields heterogeneous of operating systems, network and programming languages, different middleware, supports an open , dynamic interoperability model.But Web services is no longer meet to the large-scale enterprise computing and services. The main problem is that system needs HTTP and Web server as an intermediary. This is bound to create the bottleneck in the Web server, resulting in a slower rate of response. CORBA provides a distributed environment in heterogeneous platforms, which is transparent to the development staff of the procedure in structure. It provides heterogeneous, distributed system with a system integration functions, using object-oriented software components and bus technology. It has great advantages of cross-language, cross-platform, standardized structure, portable, flexible.But CORBA has difficulties in crossing the firewall, because the binary coding cannot unify with the existing Internet standard. More importantly, open nodes may have a different middleware, leading that the systems based on traditional middleware can hardly dynamic interaction through the Internet.
Integration of Web and CORBA are mainly two ways , one is the Web Services, clients access to CORBA server, the other integrated way is CORBA clients visit Web Services server. Because integration is applied normally through encapsulating exsiting procedures or developing new procedures to provide services. Therefore, this article mainly discussed first integration technology, Web Services Client access to CORBA Server.
Based on the existing CORBA and Web Services integration, We proposed and implemented a new Web Services and CORBA integration program based on SOAP/IIOP protocol conversion technologies. Web pages can be used only to fulfill the access and visit of CORBA object, without any additional requirements to clients. Compared with existing CORBA and Web Services program, SOAP/IIOP program has two advantages:First, it simplifies the application procedures for the development and the services;Second, it improves the response speed of the service request to the Web.Finally SOAP/IIOP gateway is applied to the remote substation monitoring .
引文
[1] 李文军，周晓聪，李师贤．分布式对象技术[M]，北京：机械工业出版社，2004
[2] A. Richling, J. Schwarz, J. Malek. Towards predictable CORBA-based Web-services Polze. Object-Oriented Real-Time Distributed Computing. 1999.5:182-191
[3] 朱其亮．CORBA原理及应用[M]，北京：北京邮电大学出版社，2002
[4] OMG编著．CORBA系统结构、原理与规范．韦乐平，薛君熬，孟洛明译．北京：电子工业出版社，2000
[5] 汪芸编著．CORBA技术及其应用．南京：东南大学出版社，1999
[6] Object Management Group. The Common Object Request Architecture and Specification. Revision 2.6, 2001
[7] Object Management Group. The Common Object Request Broker Architecture and Specification v3.0, 2002
[8] 柴晓路，梁宇奇著．Web Services技术、架构和应用[M]．北京：电子工业出版社，2003
[9] Heather Kreger．Web服务概念性体系结构[EB/OL] http://www-900.ibm.Com/developerworks/cn/webservices/ws-jaccm/pert2,2006
[10] W3C. XML Schema Part1:Structures[EB/OL]. http://www.w3c.orgrrR/xmlschema-1/,2004
[11] W3C. XML Schema Part2: Datatypes[EB/OL]. http://www.w3c.org/CR/xmlschema-2/,2004
[12] W3C.SOAP Version1.2 Part0:Primer[EB/OL]. http://www.w3c.org/rR/soap12-part0/,2003
[13] W3C. SOAP Version 1.2 Part1:Messaging Framework[EB/OL]. http://www.w3c.org/rR/soapl2-partl/,2003
[14] W3C. SOAP Version1.2 Part2: Adjuncts[EB/OL]. http://www.w3c.org/TR/soap12-part2/,2003
[15] W3C. Web Services Description Language (WSDL).Version 2.0. http://www.w3c.orgrTR/wsdl20-bindings/,2004
[16] Web Services Description Language(WSDL) 1.1[EB/OL]. http://www.w3.org/TR/WSDL,2001
[17] U. Consortium. U niversal Description, Discovery and Integration Web Site. http://www.uddi.org
[18] 柴晓路．Web服务架构与开放互操作技术[M]．北京：清华大学出版社，2002
[19] Comparison of Web Services, Java-RMI, and CORBA service Implementations. http://mercury.it.swin. edu. au/ctg/AWSAO4/Papers/gray.pdf
[20] Irmen de Jong ,Web Services/SOAP and CORBA. http://www.xs4all.nl/~irmen/comp/CORBA_vs_SOAP. html
[21] 王肇东．Corba和Web互操作的模式和优化．上海交通大学博士学位文，1999
[22] IONA Technologies (2005): Making CORBA Work in Your SOA. http://www.iona.com/whitepapers/Making_CORBA_Work in_Your_SOA_0504071. pdf
[23] Markus Aleksy, Jan Czeranski, Martin Schader. Improving the Interoperability between Web Services and CORBA Using Pontifexv A Generic Bridge Generator, International Conference on Internet and Web Applications and Services, 2006.2:166—166
[24] Guijun Wang, Robinson. An architecture for Web-enabled engineering applications based on lightweight high performance CORBA Enterprise Distributed Object Computing Conference, 2002. EDOC'02. Proceedings. Sixth International 17-20 , 2002 9:249-257
[25] Jianqiang Hu, Bin Zhou, Yan Jia, Peng Zou: Research and Implementation of CORBA Web Services. Proceedings of COMWIM of 23rd, 2004
[26] Pallemulle, Goldman, Morgan. Supporting Live Development of SOAP and CORBA Servers. Distributed Computing Systems, 2005. ICDCS 2005. Proceedings. 25th IEEE International Conference on 06-10 June 2005：553-562
[27] 马琳．CORBA/IIOP与XML结合的设想．计算机应用研究，2000．9：70-71
[28] Elfwing, Paulsson. Performance of SOAP in Web Service environment compared to CORBA. Software Engineering Conference, 2002. Ninth Asia-Pacific 4-6 Dec. 2002:84-93
[29] 胡建强，王怀民等．Web服务容器框架研究与实现．中国科协第二届优秀博士生学术年会论文集，苏州，2004：262—271
[30] IBM Developer Works[EB/OL]. http://www-900.ibm.developerworks/cn,2005
[31] 国防科大计算机学院613教研室．StarWebServices2.0用户守则，2004
[32] Object Management Group. CORBA to WSDL/SOAP Interworking Specification[S], 2003
[33] 李英俊．网络管理中CORBA Web Services数据转换的研究，重庆邮电学院学报，2006．1：128-130
[34] Object Management Group, WSDL-SOAP to CORBA Interworking [s], 2003
[35] Jandl, Alber, Radinger. Goeschka. Experiences in integration and reuse of CORBA-interfaced software with directory services and Web services System Sciences. Proceedings of the 37th Annual Hawaii International Conference on 5-8Jan. 2004:10-16
[36] Bill．Brogden．SOAP和JAVA编程指南[M]．高春蓉，谷宇，岳阳等译．北京：电子工业出版社，2002
[37] Robert Orfali，Dan Harkey．Java与CORBA客户/服务器编程[M]．北京：电子工业出版社，2004．
[38] Borland/Inprise公司．VisiBroker for Java开发程序员指南．李文军，周晓聪等译．机械工业出版社，2001
[39] 郭清锁，黎峰等．基于RTCORBA在电力分布式中的应用研究．计算机应用研究，2007．7
[40] Irfan Pyarali, Douglas C. Schmidt, Ron Cytron. Achieving End-to-End Predictability of the TAO Real-time CORBA ORB. Proceedings of the 8th IEEE Real-Time Technology and Applications Symposium, San Jose, CA, 2002.9:64-72
[41] Moser L, Mel liar-Smith M. Demonstration of fault tolerance for CORBA applications[C]. In:DARPA Information Survivability Conference and Exposition, Proceedings,2003-2004:87-89
[2] A. Richling, J. Schwarz, J. Malek. Towards predictable CORBA-based Web-services Polze. Object-Oriented Real-Time Distributed Computing. 1999.5:182-191
[3] 朱其亮．CORBA原理及应用[M]，北京：北京邮电大学出版社，2002
[4] OMG编著．CORBA系统结构、原理与规范．韦乐平，薛君熬，孟洛明译．北京：电子工业出版社，2000
[5] 汪芸编著．CORBA技术及其应用．南京：东南大学出版社，1999
[6] Object Management Group. The Common Object Request Architecture and Specification. Revision 2.6, 2001
[7] Object Management Group. The Common Object Request Broker Architecture and Specification v3.0, 2002
[8] 柴晓路，梁宇奇著．Web Services技术、架构和应用[M]．北京：电子工业出版社，2003
[9] Heather Kreger．Web服务概念性体系结构[EB/OL] http://www-900.ibm.Com/developerworks/cn/webservices/ws-jaccm/pert2,2006
[10] W3C. XML Schema Part1:Structures[EB/OL]. http://www.w3c.orgrrR/xmlschema-1/,2004
[11] W3C. XML Schema Part2: Datatypes[EB/OL]. http://www.w3c.org/CR/xmlschema-2/,2004
[12] W3C.SOAP Version1.2 Part0:Primer[EB/OL]. http://www.w3c.org/rR/soap12-part0/,2003
[13] W3C. SOAP Version 1.2 Part1:Messaging Framework[EB/OL]. http://www.w3c.org/rR/soapl2-partl/,2003
[14] W3C. SOAP Version1.2 Part2: Adjuncts[EB/OL]. http://www.w3c.org/TR/soap12-part2/,2003
[15] W3C. Web Services Description Language (WSDL).Version 2.0. http://www.w3c.orgrTR/wsdl20-bindings/,2004
[16] Web Services Description Language(WSDL) 1.1[EB/OL]. http://www.w3.org/TR/WSDL,2001
[17] U. Consortium. U niversal Description, Discovery and Integration Web Site. http://www.uddi.org
[18] 柴晓路．Web服务架构与开放互操作技术[M]．北京：清华大学出版社，2002
[19] Comparison of Web Services, Java-RMI, and CORBA service Implementations. http://mercury.it.swin. edu. au/ctg/AWSAO4/Papers/gray.pdf
[20] Irmen de Jong ,Web Services/SOAP and CORBA. http://www.xs4all.nl/~irmen/comp/CORBA_vs_SOAP. html
[21] 王肇东．Corba和Web互操作的模式和优化．上海交通大学博士学位文，1999
[22] IONA Technologies (2005): Making CORBA Work in Your SOA. http://www.iona.com/whitepapers/Making_CORBA_Work in_Your_SOA_0504071. pdf
[23] Markus Aleksy, Jan Czeranski, Martin Schader. Improving the Interoperability between Web Services and CORBA Using Pontifexv A Generic Bridge Generator, International Conference on Internet and Web Applications and Services, 2006.2:166—166
[24] Guijun Wang, Robinson. An architecture for Web-enabled engineering applications based on lightweight high performance CORBA Enterprise Distributed Object Computing Conference, 2002. EDOC'02. Proceedings. Sixth International 17-20 , 2002 9:249-257
[25] Jianqiang Hu, Bin Zhou, Yan Jia, Peng Zou: Research and Implementation of CORBA Web Services. Proceedings of COMWIM of 23rd, 2004
[26] Pallemulle, Goldman, Morgan. Supporting Live Development of SOAP and CORBA Servers. Distributed Computing Systems, 2005. ICDCS 2005. Proceedings. 25th IEEE International Conference on 06-10 June 2005：553-562
[27] 马琳．CORBA/IIOP与XML结合的设想．计算机应用研究，2000．9：70-71
[28] Elfwing, Paulsson. Performance of SOAP in Web Service environment compared to CORBA. Software Engineering Conference, 2002. Ninth Asia-Pacific 4-6 Dec. 2002:84-93
[29] 胡建强，王怀民等．Web服务容器框架研究与实现．中国科协第二届优秀博士生学术年会论文集，苏州，2004：262—271
[30] IBM Developer Works[EB/OL]. http://www-900.ibm.developerworks/cn,2005
[31] 国防科大计算机学院613教研室．StarWebServices2.0用户守则，2004
[32] Object Management Group. CORBA to WSDL/SOAP Interworking Specification[S], 2003
[33] 李英俊．网络管理中CORBA Web Services数据转换的研究，重庆邮电学院学报，2006．1：128-130
[34] Object Management Group, WSDL-SOAP to CORBA Interworking [s], 2003
[35] Jandl, Alber, Radinger. Goeschka. Experiences in integration and reuse of CORBA-interfaced software with directory services and Web services System Sciences. Proceedings of the 37th Annual Hawaii International Conference on 5-8Jan. 2004:10-16
[36] Bill．Brogden．SOAP和JAVA编程指南[M]．高春蓉，谷宇，岳阳等译．北京：电子工业出版社，2002
[37] Robert Orfali，Dan Harkey．Java与CORBA客户/服务器编程[M]．北京：电子工业出版社，2004．
[38] Borland/Inprise公司．VisiBroker for Java开发程序员指南．李文军，周晓聪等译．机械工业出版社，2001
[39] 郭清锁，黎峰等．基于RTCORBA在电力分布式中的应用研究．计算机应用研究，2007．7
[40] Irfan Pyarali, Douglas C. Schmidt, Ron Cytron. Achieving End-to-End Predictability of the TAO Real-time CORBA ORB. Proceedings of the 8th IEEE Real-Time Technology and Applications Symposium, San Jose, CA, 2002.9:64-72
[41] Moser L, Mel liar-Smith M. Demonstration of fault tolerance for CORBA applications[C]. In:DARPA Information Survivability Conference and Exposition, Proceedings,2003-2004:87-89