Tham khảo tài liệu 'xml by example- p3', công nghệ thông tin, kỹ thuật lập trình phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Entities and Notations 85 1420 ms 24 elems 9 attrs 105 spaces 97 chars If the document contains errors either syntax errors or it does not respect the structure outlined in the DTD you will have an error message. CAUTION The IBM for Java processor won t work unless you have installed a Java runtime. If there is an error message similar to Exception in thread main it means that either the classpath is incorrect make sure it points to the right directory or that you typed an incorrect class name for XML for Java XJParser and . If there is an error message similar to Exception in thread main d xml it means that the filename is incorrect in this case it points to instead of . TIP You can save some typing with batch files under Windows or shell scripts under UNIX . Adapt the path to your system replace the filename with 1 and save in a file called . The file should contain the following command java -classpath c xml4j c xml4j XJParse -p 1 Now you can validate any XML file with the following shorter command validate Entities and Notations As already mentioned in the previous chapter XML doesn t work with files but with entities. Entities are the physical representation of XML documents. Although entities usually are stored as files they need not be. In XML the document its DTD and the various files it references images stock-phrases and so on are entities. The document itself is a special entity because it is the starting point for the XML processor. The entity of the document is known as the document entity. XML does not dictate how to store and access entities. This is the task of the XML processor and it is system specific. The XML processor might have to download entities or it might use a local catalog file to retrieve the .
