Parsing xml document in java
I am trying to retrieve some data from xml document, but the program throws NullPointerException. This is the snippet of code:
if("Success".equals(nodeValue))
{
NodeList productList = xmlDocument.getElementsByTagName("Products").item(0).getChildNodes(); // gets all childs of Product node
for (int j = 0; j < productList.getLength(); j++)
{
singleProduct = xmlDocument.getElementsByTagName("Product").item(j).getChildNodes();
for(int x = 0; x < singleProduct.getLength(); x++)
开发者_如何学Python {
if(singleProduct.item(x).getNodeType() == Node.ELEMENT_NODE)
{
String nodeName = singleProduct.item(x).getNodeName();
String value = singleProduct.item(x).getChildNodes().item(0).getNodeValue();
System.err.println(x+" "+nodeName+" "+ value);
if ("ProductID".equals(nodeName))
{
id.put(xx, value);
type.put(y, singleProduct.item(x).getChildNodes().item(1).getAttributes().getNamedItem("type").getTextContent());;
xx++;
y++;
}
}
}
}
}
This part throws exception:
String value = singleProduct.item(x).getChildNodes().item(0).getNodeValue();
Exception is thrown due to the value of index inside item(0) method. How should I know the index of item in collection? I have similar program parsing XML document, it throws exception (NullPOinter) but still it runs because I catch exception. The same thing I am trying to do here, but the program does not work, terminates, though I catch Exception. How to extract correct index for item() method? Cheers
getChildNodes().item(0)
getChildNodes()
returns a NodeList
; use this value and check that its length is greater than zero.
NullPointerException
s are an indication of a programming error and should not be caught.
As an aside, you may want to look at the XPath API for extracting data from DOM trees.
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