我想从一个XML文件中的属性值,失败,但我的代码失败,下面的异常:XPath表达式用于获取属性值在Java中
11-15 16:34:42.270: DEBUG/XpathUtil(403):异常= javax.xml.xpath.XPathExpressionException:javax.xml.transform.TransformerException中:额外非法令牌: '@', '源'
下面是我用得到的代码节点列表:
private static final String XPATH_SOURCE = "array/[email protected]";
mDocument = XpathUtils.createXpathDocument(xml);
NodeList fullNameNodeList = XpathUtils.getNodeList(mDocument,
XPATH_FULLNAME);
这里是我的XpathUtils
类:
public class XpathUtils {
private static XPath xpath = XPathFactory.newInstance().newXPath();
private static String TAG = "XpathUtil";
public static Document createXpathDocument(String xml) {
try {
Log.d(TAG , "about to create document builder factory");
DocumentBuilderFactory docFactory = DocumentBuilderFactory
.newInstance();
Log.d(TAG , "about to create document builder ");
DocumentBuilder builder = docFactory.newDocumentBuilder();
Log.d(TAG , "about to create document with parsing the xml string which is: ");
Log.d(TAG ,xml);
Document document = builder.parse(new InputSource(
new StringReader(xml)));
Log.d(TAG , "If i see this message then everythings fine ");
return document;
} catch (Exception e) {
e.printStackTrace();
Log.d(TAG , "EXCEPTION OCCURED HERE " + e.toString());
return null;
}
}
public static NodeList getNodeList(Document doc, String expr) {
try {
Log.d(TAG , "inside getNodeList");
XPathExpression pathExpr = xpath.compile(expr);
return (NodeList) pathExpr.evaluate(doc, XPathConstants.NODESET);
} catch (Exception e) {
e.printStackTrace();
Log.d(TAG, "exception = " + e.toString());
}
return null;
}
// extracts the String value for the given expression
public static String getNodeValue(Node n, String expr) {
try {
Log.d(TAG , "inside getNodeValue");
XPathExpression pathExpr = xpath.compile(expr);
return (String) pathExpr.evaluate(n, XPathConstants.STRING);
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
我得到的getNodeList
方法抛出的异常。
现在,根据http://www.w3schools.com/xpath/xpath_syntax.asp,要获取属性值,请使用“@”符号。但由于某种原因,Java正在抱怨这个标志。