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--- swdev:java:files:xml_file_routines [2017/10/03 08:12]
smayr created
+++ swdev:java:files:xml_file_routines [2017/10/03 08:22] (current)
smayr
@@ Line 21: / Line 21: @@
 </company>
 </code>
+Read the list of items found in XML file:
+<code java>
+package com.acme.myproj;
+import javax.xml.parsers.DocumentBuilderFactory;
+import javax.xml.parsers.DocumentBuilder;
+import org.w3c.dom.Document;
+import org.w3c.dom.NodeList;
+import org.w3c.dom.Node;
+import org.w3c.dom.Element;
+import java.io.File;
+public class XmlFileUtils {
+  public static void ReadXmlFile(String aFileName) {
+    try {
+	File fXmlFile = new File(aFileName); // Eg: "/Users/mkyong/staff.xml"
+	DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
+	DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
+	Document doc = dBuilder.parse(fXmlFile);
+	// Optional, but recommended
+	// Read this - http://stackoverflow.com/questions/13786607/normalization-in-dom-parsing-with-java-how-does-it-work
+	doc.getDocumentElement().normalize();
+	System.out.println("Root element :" + doc.getDocumentElement().getNodeName());
+	NodeList nList = doc.getElementsByTagName("staff");
+	System.out.println("----------------------------");
+	for (int temp = 0; temp < nList.getLength(); temp++) {
+		Node nNode = nList.item(temp);
+		System.out.println("\nCurrent Element :" + nNode.getNodeName());
+		if (nNode.getNodeType() == Node.ELEMENT_NODE) {
+			Element eElement = (Element) nNode;
+			System.out.println("Staff id : " + eElement.getAttribute("id"));
+			System.out.println("First Name : " + eElement.getElementsByTagName("firstname").item(0).getTextContent());
+			System.out.println("Last Name : " + eElement.getElementsByTagName("lastname").item(0).getTextContent());
+			System.out.println("Nick Name : " + eElement.getElementsByTagName("nickname").item(0).getTextContent());
+			System.out.println("Salary : " + eElement.getElementsByTagName("salary").item(0).getTextContent());
+		}
+	}
+    } catch (Exception e) {
+	e.printStackTrace();
+    }
+  }
+}
+</code>
+To read the list of items and their children in XML file, loop through the nodes:
+<code java>
+package com.acme.myproj;
+import java.io.File;
+import javax.xml.parsers.DocumentBuilder;
+import javax.xml.parsers.DocumentBuilderFactory;
+import org.w3c.dom.Document;
+import org.w3c.dom.NamedNodeMap;
+import org.w3c.dom.Node;
+import org.w3c.dom.NodeList;
+public class XmlFileUtils
+{
+  public static void ReadAllNodes(String aFileName)
+  {
+    try {
+	File file = new File(aFileName);  // Eg. "/Users/mkyong/staff.xml"
+	DocumentBuilder dBuilder = DocumentBuilderFactory.newInstance()
+                             .newDocumentBuilder();
+	Document doc = dBuilder.parse(file);
+	System.out.println("Root element :" + doc.getDocumentElement().getNodeName());
+	if (doc.hasChildNodes()) {
+		printNote(doc.getChildNodes());
+	}
+    } catch (Exception e) {
+	System.out.println(e.getMessage());
+    }
+  }
+  private static void printNote(NodeList nodeList)
+  {
+    for (int count = 0; count < nodeList.getLength(); count++) {
+	Node tempNode = nodeList.item(count);
+	// make sure it's element node.
+	if (tempNode.getNodeType() == Node.ELEMENT_NODE) {
+		// get node name and value
+		System.out.println("\nNode Name =" + tempNode.getNodeName() + " [OPEN]");
+		System.out.println("Node Value =" + tempNode.getTextContent());
+		if (tempNode.hasAttributes()) {
+			// get attributes names and values
+			NamedNodeMap nodeMap = tempNode.getAttributes();
+			for (int i = 0; i < nodeMap.getLength(); i++) {
+				Node node = nodeMap.item(i);
+				System.out.println("attr name : " + node.getNodeName());
+				System.out.println("attr value : " + node.getNodeValue());
+			}
+		}
+		if (tempNode.hasChildNodes()) {
+			// loop again if has child nodes
+			printNote(tempNode.getChildNodes());
+		}
+		System.out.println("Node Name =" + tempNode.getNodeName() + " [CLOSE]");
+	}
+    }
+  }
+}
+</code>
+From other code, call routines as follows:
+<code java>
+private void OpenXmlDataFile()
+{
+    Path pth = Paths.get(System.getProperty("user.dir") + "/src/com/acme/myproj/data/", "staff.xml");
+    XmlFileUtils.ReadAllNodes(pth.toString());
+}
+</code>
 References:  [[https://www.mkyong.com/java/how-to-read-xml-file-in-java-dom-parser/]]