Use
JDOM xpath
Class ParsingThe jdom api class supports XPath expressions to locate nodes from XML documents. Some methods of the JDOM XPath class are listed in the following table:
| XPath Class Method |
Description |
| Selectsinglenode |
It is used to match XPath to locate a single node. |
| Selectnodes |
It is used to match XPath to locate the node set. |
| Addnamespace |
Add a namespace to match the XPath with the namespace prefix. |
In this section, use the JDOM XPath class
Catalog. xml
The process of locating nodes will be discussed. Quilt
Select
The node for method locating is modified, and the modified document is output
XML
Documentation. First, import
JDOM
PackageOrg. JDOM. xpathimport org. JDOM. XPath. *; create a saxbuildersaxbuilder saxbuilder = new saxbuilder ("org. Apache. xerces. parsers. saxparser"). parse XML documents with saxbuilder
Catalog. xml
:Org. JDOM. Document jdomdocument = saxbuilder. Build (xmldocument); xmldocument is an XML document
Catalog. xml
OfJava. Io. File
Static MethodSelectsinglenode (Java. Lang. object context, string xpathexpression) uses a specific XPath expression to locate a single node. If more than one node matches the XPath expression, the first node is selected. Use XPath to locate a journal article element attribute node level, set the journal attribute node title to Java technology, and set the article element attribute node date to January-2004. Org. JDOM. attribute levelnode = (Org. JDOM. attribute) (XPath. selectsinglenode (jdomdocument, "/CATALOG // Journal [@ Title = 'javatechnology ']" + "// article [@ date = 'january-000000']/@ level ")); the Level Attribute Value advanced is located and the level node is modified. Levelnode. setvalue ("intermediate"); The selectsinglenode method can also be used to locate nodes in XML documents. As an example, select a title node and use XPath to locate the node. Org. JDOM. element titlenode = (Org. JDOM. element) XPath. selectsinglenode (jdomdocument, "/CATALOG // Journal // article [@ date = 'january-000000']/Title "); the title node Value Design Service-Oriented Architecture frameworks with J2EE technology is located and the title node is modified. Titlenode. settext ("Service Oriented Architecture frameworks"); select all nodes specified by XPath in the static method selectnodes (Java. Lang. object context, string xpathexpression. Locate all Article nodes of journal and set the attribute title of journal to Java technology. Java. util. list nodelist = XPath. selectnodes (jdomdocument, "/CATALOG // Journal [@ Title = 'java technology '] // article"); Modify the article node and add attributes to the article node. Iterator iter = nodelist. iterator (); While (ITER. hasnext () {Org. JDOM. element element = (Org. JDOM. element) ITER. next (); element. setattribute ("section", "Java technology");} The JDOM XPath class supports locating nodes with namespaces prefix. Locate the node with a namespace and add the namespace to XPath: XPath = XPath. newinstance ("/CATALOG // Journal: Journal // article/@ Journal: Level"); XPath. addnamespace ("journal", "http://www.w3.org/2001/XMLSchema-Instance"); As above, the namespace prefixed with journal is added to the XPath object. Locate the node that contains the namespace prefix. Levelnode = (Org. JDOM. Attribute) XPath. selectsinglenode (jdomdocument); attribute node Journal: level is located. Modify this node: levelnode. setvalue ("advanced ");
Java
Program
Jdomparser. Java
Used from
XML
Document
Catalog. xml
Select a node. This section describes how to use
JDOM
Of
Xpath
Class
Select
Method from
XML
The process of locating nodes in the document. The node to be located is modified, and the modified document passesThe xmloutputter class outputs an XML document.
Catalog-modified.xml
This is the output
XML
Documentation.
Conclusion
In this tutorial
Xpath
Resolved
XML
Documentation.
Xpath
It is only used to locate nodes. As discussed in this tutorial
XPath API
Not used
Xpath
Is
XML
Document to modify the node value. To modify the value of a node,The setter method of the org. W3C. Dom package is required.
