I am basically following the example here
http://www.mkyong.com/java/how-to-read-xml-file-in-java-jdom-example/
So rather than doing something like
node.getChildText("firstname")
right??
this works fine..
But is there a way to get all the "keys" and then I can query that to get values?
Just like we do in parsing json..
JSONObject json = (JSONObject) parser.parse(value);
for (Object key : json.keySet()) {
Object val = json.get(key);
}
rather than hardcoding keys and values?
Thanks
Code for reference:
package org.random_scripts;
import java.io.File;
import java.io.IOException;
import java.util.List;
import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.JDOMException;
import org.jdom2.input.SAXBuilder;
public class XMLReader {
public static void main(String[] args) {
SAXBuilder builder = new SAXBuilder();
File xmlFile = new File("data.xml");
try {
Document document = (Document) builder.build(xmlFile);
Element rootNode = document.getRootElement();
List list = rootNode.getChildren("staff");
List children = rootNode.getChildren();
System.out.println(children);
for (int i = 0; i < list.size(); i++) {
Element node = (Element) list.get(i);
System.out.println("First Name : " + node.getChildText("firstname"));
System.out.println("Last Name : " + node.getChildText("lastname"));
System.out.println("Nick Name : " + node.getChildText("nickname"));
System.out.println("Salary : " + node.getChildText("salary"));
}
} catch (IOException io) {
System.out.println(io.getMessage());
} catch (JDOMException jdomex) {
System.out.println(jdomex.getMessage());
}
}
}
Well, if you wanted to write out all of the children of the node, you could do something like this:
List children = rootNode.getChildren();
for (int i = 0; i < list.size(); i++) {
Element node = (Element) list.get(i);
List dataNodes = node.getChildren();
for (int j = 0; j < dataNodes.size(); ++j) {
Element dataNode = (Element) dataNodes.get(j);
System.out.println(dataNode.getName() + " : " + dataNode.getText());
}
}
This would let you write out all of the children without knowing the names, with the only downside being that you wouldn't have "pretty" names for the fields (i.e. "First Name" instead of "firstname"). Of course, you'd have the same limitation in JSON - I don't know of an easy way to get pretty names for the fields unless your program has some knowledge about what the children are, which is the thing you seem to be trying to avoid.
The above code only provides the list of 1st level child under the tag.
For example::
<parent>
<child1>
<childinternal></childinternal>
</child1>
<child2></child2>
</parent>
The above code only prints child1 and child2, if you want to print even the internal nodes in depth you have to do recursive call.
To find a child has more nodes in it use, jdom api child.getContentSize(), if its greater than 1 menas it has more nodes.
Related
I need advise about how to convert XML to a custom Excel with Java
I need to convert XML to Excel with a custom layout. I found a POI and it seems like it can help with this task. But I don't have this experiences and as I understood POI works the best with in memory trees like DOM. I started to pars my XML(I can show a small part of, it's really big and goes deep)
<advantage>
<companies>
<name>Name1</name>
<name>Name2</name>
<name>Name3</name>
<name>Name4</name>
<name>Name6</name>
</companies>
<companyPreCode>
<PreCode>1</PreCode>
<PreCode>2</PreCode>
<PreCode>3</PreCode>
<PreCode>4</PreCode>
<PreCode>6</PreCode>
</companyPreCode>
by using DOM as I saw in one online tutorial like this
Document xmlDoc = getDocument("./src/xmlForTest.xml");
xmlDoc.getDocumentElement().normalize();
System.out.println("Root element of the doc is :\" "+ xmlDoc.getDocumentElement().getNodeName() + "\"");
NodeList listOfAdvantage = xmlDoc.getElementsByTagName("advantage"); //first we need to find total number of Advantage blocks
int totalAdvantage = listOfAdvantage.getLength();
System.out.println("Total no of advantage : " + totalAdvantage);
for (int s = 0; s < listOfAdvantage.getLength(); s++) //get into advantage
{
Node AdvantageNode = listOfAdvantage.item(s);
System.out.println("advantage number : " + s);
if (AdvantageNode.getNodeType() == Node.ELEMENT_NODE)
{
Element AdvantageElement = (Element) AdvantageNode;
NodeList CompanyList = AdvantageElement.getElementsByTagName("companies"); // find node companies
System.out.println("companies number : " + CompanyList.getLength());
for(int cl = 0; cl < CompanyList.getLength(); cl++) {
NodeList CompanyNameList = CompanyList.item(cl).getChildNodes(); //AdvantageElement.getElementsByTagName("name");
for (int j = 0; j < CompanyNameList.getLength(); j++) {
Node childNode = CompanyNameList.item(j);
if ("name".equals(childNode.getNodeName())) {
for (int nl = 0; nl < CompanyNameList.getLength(); nl++) {
Element CompanyNameElement = (Element) CompanyNameList.item(nl);
NodeList textFNList = CompanyNameElement.getChildNodes();
System.out.println("Company: " + nl + " :" + (textFNList.item(0)).getNodeValue().trim());
CompaniesNames.add((textFNList.item(0)).getNodeValue().trim());
}
}
}
}
}// end of if clause
}// end of for loop with s var
and now I have several questions
How to make this parsing easier? my file is big and in some places I Have the same tags for different things, like Name can be for company, product or a person. But it's getting hard to retrieve it one by one the way I did it
How to feed this data later into POI so I can start using this POI to build my Excel files? Because right now I have a set of ArrayLists with my data from different tags and I just don't know what I need to next with it
my question is "DOM parser, why do I get just one child of an element?"
I looked into this and this one, but I do not get the point.
What I'm trying to do is the following:
I have an XML file (see the extract below) :
<POITEM>
<item>
<PO_ITEM>00010</PO_ITEM>
<SHORT_TEXT>ITEM_A</SHORT_TEXT>
<MATL_GROUP>20010102</MATL_GROUP>
<AGREEMENT>4600010076</AGREEMENT>
<AGMT_ITEM>00010</AGMT_ITEM>
<HL_ITEM>00000</HL_ITEM>
<NET_PRICE>1.000000000</NET_PRICE>
<QUANTITY>1.000</QUANTITY>
<PO_UNIT>EA</PO_UNIT>
</item>
<item>
<PO_ITEM>00020</PO_ITEM>
<SHORT_TEXT>ITEM_B</SHORT_TEXT>
<MATL_GROUP>20010102</MATL_GROUP>
<AGREEMENT>4600010080</AGREEMENT>
<AGMT_ITEM>00020</AGMT_ITEM>
<HL_ITEM>00000</HL_ITEM
<NET_PRICE>5.000000000</NET_PRICE>
<QUANTITY>5.000</QUANTITY>
<PO_UNIT>EA</PO_UNIT>
</item>
</POITEM>
I only want to extract <PO_ITEM>, <SHORT_TEXT>, <MATL_GROUP>, <NET_PRICE>, <QUANTITY> and <PO_UNIT> and write it into another, smaller XML file.
So this is my code:
nodes = dcmt.getElementsByTagName("POITEM");
Element rootElement2 = doc1.createElement("PO_POSITIONS");
rootElement1.appendChild(rootElement2);
Element details2 = doc1.createElement("PO_DETAILS");
rootElement2.appendChild(details2);
for (int i = 0; i < nodes.getLength(); i++) {
Node node = nodes.item(i);
if (node.getNodeType() == Node.ELEMENT_NODE) {
Element element = (Element) node;
Element position = doc1.createElement("position");
details2.appendChild(position);
Element poItm = doc1.createElement("PO_ITEM");
poItm.appendChild(doc1.createTextNode(getValue("PO_ITEM", element)));
position.appendChild(poItm);
Element matlGrp = doc1.createElement("MATL_GROUP");
matlGrp.appendChild(doc1.createTextNode(getValue("MATL_GROUP",element)));
position.appendChild(matlGrp);
Element poUnit = doc1.createElement("PO_UNIT");
poUnit.appendChild(doc1.createTextNode(getValue("PO_UNIT",element)));
position.appendChild(poUnit);
Element netPrice = doc1.createElement("NET_PRICE");
netPrice.appendChild(doc1.createTextNode(getValue("NET_PRICE",element)));
position.appendChild(netPrice);
Element shortTxt = doc1.createElement("SHORT_TEXT");
shortTxt.appendChild(doc1.createTextNode(getValue("SHORT_TEXT",element)));
position.appendChild(shortTxt);
//Element matl = doc2.createElement("MATERIAL");
//matl.appendChild(doc2.createTextNode(getValue("MATERIAL",element)));
//details2.appendChild(matl);
Element qnty = doc1.createElement("QUANTITY");
qnty.appendChild(doc1.createTextNode(getValue("QUANTITY",element)));
position.appendChild(qnty);
/*Element preqNr = doc1.createElement("PREQ_NO");
preqNr.appendChild(doc1.createTextNode(getValue("PREQ_NO",element)));
details2.appendChild(preqNr); */
}
}
So far so good, I'm getting a new XML File, but it only holds the first entry, so as i understand it, by the nodes = dcmt.getElementsByTagName("POITEM"); gets into the first <item> until the first </item> and then gets out of the loop. So how do I manage step into the next item? Do I need to create some kind of loop, to access the next <item> ?
By the way, changing the structure of the XML file is no option, since I get the file from an interface.
Or do I make a mistake while writing the new XML file?
The output looks like this:
<PO_POSITIONS>
<PO_DETAILS>
<position>
<PO_ITEM>00010</PO_ITEM>
<MATL_GROUP>20010102</MATL_GROUP>
<PO_UNIT>EA</PO_UNIT>
<NET_PRICE>1.00000000</NET_PRICE>
<SHORT_TEXT>ITEM_A</SHORT_TEXT>
<QUANTITY>1.000</QUANTITY>
</position>
</PO_DETAILS>
</PO_POSITIONS>
You could parse it yourself, it's kind of a pain. When I did xml way back when, we used to use stylesheets to do these kinds of transformations. Something like this post: How to transform XML with XSL using Java
If that's not an option, then to do it by hand (I omitted the new document construction, but you can see where it goes):
import java.io.File;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.junit.Test;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
public class XMLTest {
#Test
public void testXmlParsing() throws Exception {
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.parse(new File("/Users/aakture/Documents/workspace-sts-2.9.1.RELEASE/smartfox/branches/trunk/java/gelato/src/test/resources/sample.xml").getAbsolutePath());
Node poItem = doc.getElementsByTagName("POITEM").item(0);
NodeList poItemChildren = poItem.getChildNodes();
for (int i = 0; i < poItemChildren.getLength(); i++) {
Node item = poItemChildren.item(i);
NodeList itemChildren = item.getChildNodes();
for (int j = 0; j < itemChildren.getLength(); j++) {
Node itemChild = itemChildren.item(j);
if("PO_ITEM".equals(itemChild.getNodeName())) {
System.out.println("found PO_ITEM: " + itemChild.getTextContent());
}
if("MATL_GROUP".equals(itemChild.getNodeName())) {
System.out.println("found MATL_GROUP: " + itemChild.getTextContent());
}
}
}
}
}
I have to develop an android application.
Here i have follows following xml format.
<Product>
<product name="viki" productid="111">
<ProductType>
<producttype>Nokia</producttype>
<producttype>Samsung</producttype>
</ProductType>
</product>
</Product>
Here i have to get the producttype for particluar product.so i have wrote the following code:
if(subCategoryChildNode.hasChildNodes()){
// parse 'Subcategory' childs
NodeList productNL = subCategoryChildElmt.getElementsByTagName("product");
if(productNL.getLength() > 0){
ArrayList<Product> productAL = new ArrayList<Product>();
Product productBean = null;
for(int pCnt=0;pCnt<productNL.getLength();pCnt++){
Node productNode = productNL.item(pCnt);
Element productElmt = null;
// parse 'product' tag attributes
if(productNode.hasAttributes()){
productBean = new Product();
productElmt = (Element)productNode;
productBean.setmProductName(productElmt.getAttribute("name"));
}
if(productNode.hasChildNodes()){
NodeList productTypeNL = productElmt.getElementsByTagName("ProductType");
if(productTypeNL.getLength() > 0){
ArrayList<ProductType> ProductTypeAL = new ArrayList<ProductType>();
ProductType productTypeBean = null;
for(int ptCnt=0;ptCnt<productTypeNL.getLength();ptCnt++){
Node productTypeNode = productTypeNL.item(ptCnt);
Element productTypeElmt = null;
if(productTypeNode.hasChildNodes()){
productTypeBean = new ProductType();
productTypeElmt = (Element)productTypeNode;
productTypeBean.setmProductType(XMLfunctions.getValue(productTypeElmt,"producttype"));
System.out.println("Product Types are "+ " "+XMLfunctions.getValue(productTypeElmt,"producttype"));
ProductTypeAL.add(productTypeBean);
}
productBean.setmProductTypes(ProductTypeAL);
}
productAL.add(productBean);
}
}
subCategoryBean.setmProducts(productAL);
}
}
subCategoryAL.add(subCategoryBean);
}
Here am getting the value is nokia alone.but i need to display the value nokia,samsung...if i have to run the app means getting single value.but i need to get the list of all values..
What's wrong in my code .. please check and give me solution fot these ???
The reason you're getting only one <producttype> (Nokia) instead of the complete list because you're looping over the length of <ProductType> nodes thinking you're looping over the <producttype> ones.
So, you need another inner loop to cover all the child product type nodes like
for(int ptCnt=0; ptCnt < productTypeNL.getLength(); ptCnt++) {
Node productTypeNode = productTypeNL.item(ptCnt);
if(productTypeNode.hasChildNodes()){
NodeList childProductTypeNL = productTypeNode.getChildNodes();
System.out.print("Product Types are: ");
for (int cptCnt=0; cptCnt < childProductTypeNL.getLength(); cptCnt++) {
productTypeBean = new ProductType();
productTypeBean.setmProductType (
childProductTypeNL.item(cptCnt).getTextContent());
System.out.print(productTypeBean.getmProductType() + ", ");
ProductTypeAL.add(productTypeBean);
}
}
productBean.setmProductTypes(ProductTypeAL);
}
I've directly used the Node.getChildNodes() and Node.getTextContexnt() methods, instead of type casting to Element first and using its methods or the XMLfunctions utility class.
I also recommend using different names for child nodes instead of relying on using a different case to avoid such problems in future. A simple way to avoid name collision (when you're not able to come up with a different name) is to simply use a plural like <ProductTypes> for the parent tag.
However, a better approach when you need to parse deep within a DOM tree is to use an XPath to directly get the list of nodes you're interested in. I'm not entirely sure what the program does but just to give you an example an XPath like
String xpath = "//product[#name=\"viki\"]/ProductType/producttype";
would give you the NodeList for <producttype> nodes directly.
I'd say one of the problem of your code (might be others), is that you declare your productTypeBean and productTypeElmt before your for loop, and since it's not required after, it isn't needed.
if(subCategoryChildNode.hasChildNodes()){
// parse 'Subcategory' childs
NodeList productNL = subCategoryChildElmt.getElementsByTagName("product");
if(productNL.getLength() > 0){
ArrayList<Product> productAL = new ArrayList<Product>();
Product productBean = null;
for(int pCnt=0;pCnt<productNL.getLength();pCnt++){
Node productNode = productNL.item(pCnt);
Element productElmt = null;
// parse 'product' tag attributes
if(productNode.hasAttributes()){
productBean = new Product();
productElmt = (Element)productNode;
productBean.setmProductName(productElmt.getAttribute("name"));
}
if(productNode.hasChildNodes()){
NodeList productTypeNL = productElmt.getElementsByTagName("ProductType");
if(productTypeNL.getLength() > 0){
ArrayList<ProductType> ProductTypeAL = new ArrayList<ProductType>();
for(int ptCnt=0;ptCnt<productTypeNL.getLength();ptCnt++){
Node productTypeNode = productTypeNL.item(ptCnt);
if(productTypeNode.hasChildNodes()){
ProductType productTypeBean = new ProductType();
Element productTypeElmt = (Element)productTypeNode;
productTypeBean.setmProductType(XMLfunctions.getValue(productTypeElmt,"producttype"));
System.out.println("Product Types are "+ " "+XMLfunctions.getValue(productTypeElmt,"producttype"));
ProductTypeAL.add(productTypeBean);
}
productBean.setmProductTypes(ProductTypeAL);
}
productAL.add(productBean);
}
}
subCategoryBean.setmProducts(productAL);
}
}
subCategoryAL.add(subCategoryBean);
}
So I am having a lot of trouble reading this XML file:
<?xml version = "1.0" encoding = "UTF-8"?>
<!--this version of Eclipse dosn't support direct creation of XML files-->
<!-- you have to create one in notepad and then copy/paste it into Eclipse-->
<root testAttribute = "testValue">
<data>Phoebe</data>
<data>is</data>
<data>a</data>
<data>puppy!</data>
<secondElement testAttribute = "testValueAgain">
<data2>Poop</data2>
<data2>Doopy</data2>
</secondElement>
</root>
In my java file I get a NullPointerException in this one line.
Here's the code: (I'll point out where the exception occurs)
import javax.xml.parsers.*;
import org.w3c.dom.*;
import org.xml.sax.*;
import java.io.*;
public class Reading {
public static void main(String args[]){
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
try {
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse(new File("res/Test.xml"));
////////////////////GET ELEMENTS//////////////////
Element rootElement = doc.getDocumentElement();
System.out.println("Root element: " + doc.getDocumentElement().getNodeName());
System.out.println("testAttribute for root element: "
+ rootElement.getAttribute("testAttribute"));
Element secondElement = doc.getElementById("secondElement");
System.out.println("testAttribute for second element: " +
secondElement.getAttribute("testAttribute")); //THIS IS THE LINE
NodeList list = rootElement.getElementsByTagName("data");
NodeList list2 = rootElement.getElementsByTagName("data2");
//////////////////////////////////
for(int i = 0; i < list.getLength(); i++){
Node dataNode = list.item(i);
System.out.println("list index: " + i + " data at that index: " +
dataNode.getTextContent());
}
for(int i = 0; i < list2.getLength(); i++){
Node dataNode = list2.item(i);
System.out.println("list2 index: " + i + " data at that index: " +
dataNode.getTextContent());
}
}catch(ParserConfigurationException e){
e.printStackTrace();
}catch(IOException e){
e.printStackTrace();
}catch(SAXException e){
e.printStackTrace();
}
}
}
Can you guys check out my code and tell me what I can do to avoid the NullPointerException? I'm really frustrated right now. Thanks!
P.S. some of you guys answered about the line above the line that got the exception. The exception occurs when I try to PRINT OUT the testAttribute value in the secondaryElement element.
getElementByID is not what you think it is, thus returns null (there are no id="..." attributes).
The quick answer is that your secondElement is null. The reason is because you have no element with id="secondElement". Your code expects the document to contain something like
<myelement id="secondElement">...</myelement>
I can't fetch text value with Node.getNodeValue(), Node.getFirstChild().getNodeValue() or with Node.getTextContent().
My XML is like
<add job="351">
<tag>foobar</tag>
<tag>foobar2</tag>
</add>
And I'm trying to get tag value (non-text element fetching works fine). My Java code sounds like
Document doc = db.parse(new File(args[0]));
Node n = doc.getFirstChild();
NodeList nl = n.getChildNodes();
Node an,an2;
for (int i=0; i < nl.getLength(); i++) {
an = nl.item(i);
if(an.getNodeType()==Node.ELEMENT_NODE) {
NodeList nl2 = an.getChildNodes();
for(int i2=0; i2<nl2.getLength(); i2++) {
an2 = nl2.item(i2);
// DEBUG PRINTS
System.out.println(an2.getNodeName() + ": type (" + an2.getNodeType() + "):");
if(an2.hasChildNodes())
System.out.println(an2.getFirstChild().getTextContent());
if(an2.hasChildNodes())
System.out.println(an2.getFirstChild().getNodeValue());
System.out.println(an2.getTextContent());
System.out.println(an2.getNodeValue());
}
}
}
It prints out
tag type (1):
tag1
tag1
tag1
null
#text type (3):
_blank line_
_blank line_
...
Thanks for the help.
I'd print out the result of an2.getNodeName() as well for debugging purposes. My guess is that your tree crawling code isn't crawling to the nodes that you think it is. That suspicion is enhanced by the lack of checking for node names in your code.
Other than that, the javadoc for Node defines "getNodeValue()" to return null for Nodes of type Element. Therefore, you really should be using getTextContent(). I'm not sure why that wouldn't give you the text that you want.
Perhaps iterate the children of your tag node and see what types are there?
Tried this code and it works for me:
String xml = "<add job=\"351\">\n" +
" <tag>foobar</tag>\n" +
" <tag>foobar2</tag>\n" +
"</add>";
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
ByteArrayInputStream bis = new ByteArrayInputStream(xml.getBytes());
Document doc = db.parse(bis);
Node n = doc.getFirstChild();
NodeList nl = n.getChildNodes();
Node an,an2;
for (int i=0; i < nl.getLength(); i++) {
an = nl.item(i);
if(an.getNodeType()==Node.ELEMENT_NODE) {
NodeList nl2 = an.getChildNodes();
for(int i2=0; i2<nl2.getLength(); i2++) {
an2 = nl2.item(i2);
// DEBUG PRINTS
System.out.println(an2.getNodeName() + ": type (" + an2.getNodeType() + "):");
if(an2.hasChildNodes()) System.out.println(an2.getFirstChild().getTextContent());
if(an2.hasChildNodes()) System.out.println(an2.getFirstChild().getNodeValue());
System.out.println(an2.getTextContent());
System.out.println(an2.getNodeValue());
}
}
}
Output was:
#text: type (3): foobar foobar
#text: type (3): foobar2 foobar2
If your XML goes quite deep, you might want to consider using XPath, which comes with your JRE, so you can access the contents far more easily using:
String text = xp.evaluate("//add[#job='351']/tag[position()=1]/text()",
document.getDocumentElement());
Full example:
import static org.junit.Assert.assertEquals;
import java.io.StringReader;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathFactory;
import org.junit.Before;
import org.junit.Test;
import org.w3c.dom.Document;
import org.xml.sax.InputSource;
public class XPathTest {
private Document document;
#Before
public void setup() throws Exception {
String xml = "<add job=\"351\"><tag>foobar</tag><tag>foobar2</tag></add>";
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
document = db.parse(new InputSource(new StringReader(xml)));
}
#Test
public void testXPath() throws Exception {
XPathFactory xpf = XPathFactory.newInstance();
XPath xp = xpf.newXPath();
String text = xp.evaluate("//add[#job='351']/tag[position()=1]/text()",
document.getDocumentElement());
assertEquals("foobar", text);
}
}
I use a very old java. Jdk 1.4.08 and I had the same issue. The Node class for me did not had the getTextContent() method. I had to use Node.getFirstChild().getNodeValue() instead of Node.getNodeValue() to get the value of the node. This fixed for me.
If you are open to vtd-xml, which excels at both performance and memory efficiency, below is the code to do what you are looking for...in both XPath and manual navigation... the overall code is much concise and easier to understand ...
import com.ximpleware.*;
public class queryText {
public static void main(String[] s) throws VTDException{
VTDGen vg = new VTDGen();
if (!vg.parseFile("input.xml", true))
return;
VTDNav vn = vg.getNav();
AutoPilot ap = new AutoPilot(vn);
// first manually navigate
if(vn.toElement(VTDNav.FC,"tag")){
int i= vn.getText();
if (i!=-1){
System.out.println("text ===>"+vn.toString(i));
}
if (vn.toElement(VTDNav.NS,"tag")){
i=vn.getText();
System.out.println("text ===>"+vn.toString(i));
}
}
// second version use XPath
ap.selectXPath("/add/tag/text()");
int i=0;
while((i=ap.evalXPath())!= -1){
System.out.println("text node ====>"+vn.toString(i));
}
}
}