I have tried a lot of times but I did not how to retrive a value from XML using Java. I tried to use DOM and Xpath. Please help. I can use a String Writer to printout the XML so I know the XML is not empty.
Document doc = parseXML(connection.getInputStream());
doc.getDocumentElement().normalize();
System.out.println("Root element :" + doc.getDocumentElement().getNodeName());
XPath xPath = XPathFactory.newInstance().newXPath();
XPathExpression expr = xPath.compile("/xml_api_reply/weather/current_conditions/temp_f/text()");
Object result = expr.evaluate(doc, XPathConstants.NODESET);
NodeList nodes = (NodeList) result;
for (int i = 0; i < nodes.getLength(); i++) {
System.out.println(nodes.item(i).getNodeValue());
}
The content of XML :
<xml_api_reply version="1">
<weather module_id="0" tab_id="0" mobile_row="0" mobile_zipped="1" row="0" section="0">
<current_conditions>
<condition data="Clear"/>
<temp_f data="49"/>
<temp_c data="9"/>
</current_conditions>
</weather>
</xml_api_reply>
It seems that it did not go in to the for loop because nodes is null.
Your XPath expression evaluates to the (non existant) text-nodes underneath temp_f. Yet, you need the value of the data attribute:
/xml_api_reply/weather/current_conditions/temp_f/#data
may do the trick.
Did you try this implementation?
http://www.mkyong.com/java/how-to-read-xml-file-in-java-dom-parser/
Related
got a little problem. I have the following code:
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse("result1.xml");
XPathFactory xPathfactory = XPathFactory.newInstance();
XPath xpath = xPathfactory.newXPath();
XPathExpression expr = xpath.compile("//element");
String elements = (String) expr.evaluate(doc, XPathConstants.STRING);
What i get :
jcruz0#exblog.jp
Cheryl
Blake
195115
What i want:
<person>
<email>jcruz0#exblog.jp</email>
<firstname>Cheryl</firstname>
<lastname>Blake</lastname>
<number>195115</number>
</person>
So as you can see i want the full XML tree. Not just the NodeValue.
Maybe somebody knows the trick.
Thanks for any help.
You got the string value of the selected XML element because you specified XPathConstants.STRING to XPathExpression.evaluate().
Instead, specify a return type of XPathConstants.NODE if you know for sure that your XPath will select a single element,
String elements = (String) expr.evaluate(doc, XPathConstants.NODE);
or XPathConstants.NODESET for multiple elements, which you would then iterate over to process as necessary.
Something like this can be done.
XPathExpression expr = xpath.compile("/person");
NodeList elements = (NodeList) expr.evaluate(doc, XPathConstants.NODESET);
for (int i = 0; i < elements.getLength(); i++) {
// the person node
System.out.println(elements.item(i).getNodeName());
for (int x = 0; x < elements.item(i).getChildNodes().getLength(); x++) {
// the elements under person
if (elements.item(i).getChildNodes().item(x).getNodeType() == Node.ELEMENT_NODE) {
System.out.println("\t" + elements.item(i).getChildNodes().item(x).getNodeName() + " - " + elements.item(i).getChildNodes().item(x).getTextContent());
}
}
}
Output
person
email - jcruz0#exblog.jp
firstname - Cheryl
lastname - Blake
number - 195115
You can use the nodes to do what you want, or wrap them in < and > if you just want to print them.
I have to parse an xml file in which I have many name value pairs.
I have to update the value in case it matches a given name.
I opted for DOM parsing as it can easily traverse any part and can quickly update the value.
It is however giving me some wired results when I am running it on my sample file.
I am new to DOM so if someone can help it can solve my problem.
I tried various things but all resulting in either null values for content or #text node name.
I am not able to get the text content of the tag.
DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
Document document = documentBuilder.parse(xmlFilePath);
//This will get the first NVPair
Node NVPairs = document.getElementsByTagName("NVPairs").item(0);
//This should assign nodes with all the child nodes of NVPairs. This should be ideally
//<nameValuePair>
NodeList nodes = NVPairs.getChildNodes();
for (int i = 0; i < nodes.getLength(); i++) {
Node node = nodes.item(i);
// I think it will consider both starting and closing tag as node so checking for if it has
//child
if(node.hasChildNodes())
{
//This should give me the content in the name tag.
//However this is not happening
if ("Tom".equals(node.getFirstChild().getTextContent())) {
node.getLastChild().setTextContent("2000000");
}
}
}
Sample xml
<?xml version="1.0" encoding="UTF-8" standalone="no"?><application>
<NVPairs>
<nameValuePair>
<name>Tom</name>
<value>12</value>
</nameValuePair>
<nameValuePair>
<name>Sam</name>
<value>121</value>
</nameValuePair>
</NVPairs>
#getChildNodes() and #getFirstChild() returns all kinds of nodes, not just Element nodes, and in this case the first child of <name>Tom</name> is a Text node (with newline and blanks). So your test will never return true.
However, in cases like this, it always much more convenient to use XPath:
XPath xpath = XPathFactory.newInstance().newXPath();
NodeList nodes = (NodeList) xpath.evaluate(
"//nameValuePair/value[preceding-sibling::name = 'Tom']", document,
XPathConstants.NODESET);
for (int i = 0; i < nodes.getLength(); i++) {
Node node = nodes.item(i);
node.setTextContent("2000000");
}
I.e., return all <name> elements that has a preceding sibling element <name> with value 'Tom'.
I have this code:
org.w3c.dom.Document doc = docBuilder.parse(representation.getStream());
Element element = doc.getDocumentElement();
NodeList nodeList = element.getElementsByTagName("xnat:MRSession.scan.file");
for (int i = 0; i < nodeList.getLength(); i++) {
Node node = nodeList.item(i);
if (node.getNodeType() == Node.ELEMENT_NODE) {
// do something with the current element
my problem is with getElementsByTagName("xnat:MRSession.scan.file")
my xml looks like this:
<?xml version="1.0" encoding="UTF-8"?><xnat:MRSession "REMOVED DATA IGNORE">
<xnat:sharing>
<xnat:share label="23_MR1" project="BOGUS_GSU">
<!--hidden_fields[xnat_experimentData_share_id="1",sharing_share_xnat_experimentDa_id="xnat_E00001"]-->
</xnat:share>
</xnat:sharing>
<xnat:fields>
<xnat:field name="studyComments">
<!--hidden_fields[xnat_experimentData_field_id="1",fields_field_xnat_experimentDat_id="xnat_E00001"]-->S</xnat:field>
</xnat:fields>
<xnat:subject_ID>xnat_S00002</xnat:subject_ID>
<xnat:scanner manufacturer="GE MEDICAL SYSTEMS" model="GENESIS_SIGNA"/>
<xnat:prearchivePath>/home/ryan/xnat_data/prearchive/BOGUS_OUA/20120717_131900137/23_MR1</xnat:prearchivePath>
<xnat:scans>
<xnat:scan ID="1" UID="1.2.840.113654.2.45.2.108830" type="SAG LOCALIZER" xsi:type="xnat:mrScanData">
<!--hidden_fields[xnat_imageScanData_id="1"]-->
<xnat:image_session_ID>xnat_E00001</xnat:image_session_ID>
<xnat:quality>usable</xnat:quality>
<xnat:series_description>SAG LOCALIZER</xnat:series_description>
<xnat:scanner manufacturer="GE MEDICAL SYSTEMS" model="GENESIS_SIGNA"/>
<xnat:frames>29</xnat:frames>
<xnat:file URI="/home/ryan/xnat_data/archive/BOGUS_OUA/arc001/23_MR1/SCANS/1/DICOM/scan_1_catalog.xml" content="RAW" file_count="29" file_size="3968052" format="DICOM" label="DICOM" xsi:type="xnat:resourceCatalog">
So Basically I need to be able to iterate through all the xnat:MRSession/xnat:scan/xnat:file
elements and make some changes. Problem is
getElementsByTagName("xnat:MRSession.scan.file")
Is always null. Please help. Thanks
You could try the following using XPath:
Document document = // the parsed document
XPathFactory xPathFactory = XPathFactory.newInstance();
NodeList allFileNodes = xPathFactory.newXPath().evaluate("\\XNAT_NAMESPACE:file", document.getDocumentElement(), XPathConstants.NODESET);
Instead XNAT_NAMESPACE you would need to specify the exact namespace that is meant with the prefix "xnat" in your example.
Following is the XML file -
<Country>
<Group>
<C>Tokyo</C>
<C>Beijing</C>
<C>Bangkok</C>
</Group>
<Group>
<C>New Delhi</C>
<C>Mumbai</C>
</Group>
<Group>
<C>Colombo</C>
</Group>
</Country>
I want to save the name of Cities to a text file using Java & XPath -
Below is the Java code which is unable to do the needful.
.....
.....
DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
domFactory.setNamespaceAware(true);
DocumentBuilder builder = domFactory.newDocumentBuilder();
Document doc = builder.parse("Continent.xml");
XPath xpath = XPathFactory.newInstance().newXPath();
// XPath Query for showing all nodes value
XPathExpression expr = xpath.compile("//Country/Group");
Object result = expr.evaluate(doc, XPathConstants.NODESET);
NodeList nodes = (NodeList) result;
BufferedWriter out = new BufferedWriter(new FileWriter("Cities.txt"));
Node node;
for (int i = 0; i < nodes.getLength(); i++)
{
node = nodes.item(i);
String city = xpath.evaluate("C",node);
out.write(" " + city + "\r\n");
}
out.close();
.....
.....
Can somebody help me to get the required output?
You are getting only the first city because that's what you asked for. Your first XPATH expression returns all the Group nodes. You iterate over these and evaluate the XPATH C relative to each Group, returning a single city.
Just change the first XPATH to //Country/Group/C and eliminate the second XPATH altogether -- just print the text value of each node returned by the first XPATH.
I.e.:
XPathExpression expr = xpath.compile("//Country/Group/C");
...
for (int i = 0; i < nodes.getLength(); i++)
{
node = nodes.item(i);
out.write(" " + node.getTextContent() + "\n");
}
<subjectOf typeCode="SUBJ">
<annotation classCode="ACT" moodCode="EVN">
<realmCode code="QD" />
<code code="SPECIALNOTE"></code>
<text><![CDATA[<strong>** New York State approval pending. This test is not available for New York State patient testing **</br> ]]></text>
</annotation>
</subjectOf>
<subjectOf typeCode="SUBJ">
<annotation classCode="ACT" moodCode="EVN">
<realmCode code="QD" />
<code code="PREFERREDSPECIMEN"></code>
<text><![CDATA[2 mL Second void urine <strong>or </strong>2-hour urine <strong>or </strong> 2 mL Urine with no preservative]]></text>
</annotation>
</subjectOf>
In DOM parsing, how can I traverse through the above XML and get the <text> tag value depending upon a <code> tag attribute having a given value. For example, I want to get the following text:
<strong>** New York State approval pending. This test is not available
for New York State patient testing **</br>
...based on the <code> tag with a code attribute where value="SPECIALNOTE".
public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException, XPathExpressionException {
DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
domFactory.setNamespaceAware(true);
DocumentBuilder builder = domFactory.newDocumentBuilder();
Document doc = builder.parse("xml.xml");
XPath xpath = XPathFactory.newInstance().newXPath(); // XPath Query for showing all nodes value
XPathExpression expr = xpath.compile("/testCodeIdentifier/subjectOf/subjectOf/annotation/code[#code='SPECIALNOTE']");
Object result = expr.evaluate(doc, XPathConstants.NODESET);
NodeList nodes = (NodeList) result;
for (int i = 0; i < nodes.getLength(); i++) {
System.out.println("........"+nodes.item(i).getNodeValue()+"........");
}
}
}
Appreciate the help in advance...
First, your XPath expression has an error; subjectOf is repeated unnecessarily:
/subjectOf/subjectOf
Now, assuming you really do need a reference to the code node that precedes the target text element, then use the following:
XPathExpression expr = xpath.compile(
"/testCodeIdentifier/subjectOf/annotation/code[#code='SPECIALNOTE']");
Node node = (Node) expr.evaluate(doc, XPathConstants.NODE);
System.out.println(getNextElementSibling(node).getTextContent());
Where getNextElementSibling is defined as follows:
public static Node getNextElementSibling(Node node) {
Node next = node;
do {
next = next.getNextSibling();
} while ((next != null) && (next.getNodeType() != Node.ELEMENT_NODE));
return next;
}
A couple of notes about this:
The reason that getNextSibling did not originally work for you is (most likely) because the next sibling of the referenced code element is a text node, not an element node. (The whitespace between code and text is significant.) That's why we need getNextElementSibling.
We're selecting a single node, so we're using XPathConstants.NODE instead if XPathConstants.NODELIST
Note that you should probably just do as #Lukas suggests and modify your XPath expression to directly select the target text.
Here's how to get the text directly (as a String):
XPathExpression expr = xpath.compile(
"/testCodeIdentifier/subjectOf/annotation[code/#code='SPECIALNOTE']/text/text()");
String text = (String) expr.evaluate(doc, XPathConstants.STRING);
System.out.println(text);
Here's how to first get a reference to the element and then retrieve the contents of its CDATA section:
XPathExpression expr = xpath.compile(
"/testCodeIdentifier/subjectOf/annotation[code/#code='SPECIALNOTE']/text");
Node text = (Node) expr.evaluate(doc, XPathConstants.NODE);
System.out.println(text.getTextContent());
Fix your XPath expression like this:
/testCodeIdentifier/subjectOf/annotation[code/#code='SPECIALNOTE']/text
You could then, for instance, access the CDATA content using
Node.getTextContent();
UPDATE: The above XPath seemed correct at the time I posted it. In the meantime, you have completely changed your XML code and now, the XPath would read
/testCodeIdentifier/subjectOf/code/subjectOf/annotation[code/#code='SPECIALNOTE']/text
Or, because I am guessing that this question is so messy, it's still wrong, just do:
//annotation[code/#code='SPECIALNOTE']/text
Finally i have got the answer for my question by myself.... Below code is being working for my XML to be parsed...
XPath xpath = XPathFactory.newInstance().newXPath();
// XPath Query for showing all nodes value
XPathExpression expr = xpath.compile("//testCodeIdentifier/subjectOf/order/subjectOf/annotation/code[#code='SPECIALNOTE']/following-sibling::text/text()");
Object result = expr.evaluate(doc, XPathConstants.NODESET);
NodeList nodes = (NodeList) result;
for (int i = 0; i < nodes.getLength(); i++) {
System.out.println(nodes.item(i).getNodeValue());
}
Thank you people who have ansewered in this post but this is a possible solution for it. Have a mark on it.