Research And Implementation Of XML Parsing Technology For Embedded Web Services

With the rapid development of Internet technology and Distributed computing technology, web services, which are called the third IT revolution of computer in the computer realm, already manifest the enormous business opportunity progressively, the software industry is facing most extensive "shuffling". Web services break down the distinctions between Internet, standalone applications and computing devices, they can integrate distributed systems seamlessly on a grand scale and are the most perfect solutions for interoperability between embedded systems or between embedded devices and enterprise systems at present. Web services applied to embedded system is a kind of inevitable trend, this will bring the enormous development opportunity for embedded products.Obtaining immense success in distributed computing feild, web services benefit from a set of technical specifications that realize interoperability .and all its technical specifications regard XML as the core of ground floor and framework foundation. Then XML processing is the basic capacity required by embedded web services .So XML parsing is the most key problem in the embedded web service system, and this is the main research content of this paper, too.Beginning with analyzing advantages of web service technology, this paper systematically outlines a series of technical specifications that realize interoperability, especially SOAP and XML. After analyzing and comparing the three XML parsing technologies emphatically, this paper designs and realizes a non-validate XML parser based on XPP parsing technology, which is aiming for embedded system. During the implement, this paper puts forward a concrete scheme to manage XML data so as to reduce using memory as much as possible, and builds Finite State Model to realize flexible XML parsing, according to XML data structure. On this basis, this paper introduces a few kinds of programming modes with concrete instance to use the parser. Using the parser, the application can only process data partly according to the needs of application. Thus the parser is suitable for processing XML in the limited environment of resource, and offers essential support for realizing embedded web services further.Finally, based on SOPC hardware platform of Altera Nios II soft nuclear processor and MicroC/OS-II software platform, this paper designs and realizes anembedded SOAP server and presents the test result, on the basis of realizing HTTP protocol and XML parser. All software in the system is programmed in C language with strong portability. In the testing, this paper has used several kinds of programming model about the XML parser synthetically and has proved the validity of the XML parser.