Introduction to XPath

2016-06-08 23:13:45 +02:00
parent 9be037e24f
commit a156fa8590
6 changed files with 480 additions and 1 deletions
@@ -0,0 +1,193 @@
+package com.baeldung.xml;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.util.Iterator;
+
+import javax.xml.namespace.NamespaceContext;
+import javax.xml.parsers.DocumentBuilder;
+import javax.xml.parsers.DocumentBuilderFactory;
+import javax.xml.parsers.ParserConfigurationException;
+import javax.xml.xpath.XPath;
+import javax.xml.xpath.XPathConstants;
+import javax.xml.xpath.XPathExpressionException;
+import javax.xml.xpath.XPathFactory;
+
+import org.w3c.dom.Document;
+import org.w3c.dom.Node;
+import org.w3c.dom.NodeList;
+import org.xml.sax.SAXException;
+
+public class DefaultParser {
+    
+    private File file;
+
+    public DefaultParser(File file) {
+        this.file = file;
+    }
+
+    public NodeList getFirstLevelNodeList() {
+        NodeList nodeList = null;
+        try {
+            FileInputStream fileIS = new FileInputStream(this.getFile());
+            DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
+
+            DocumentBuilder builder = builderFactory.newDocumentBuilder();
+
+            Document xmlDocument = builder.parse(fileIS);
+
+            XPath xPath = XPathFactory.newInstance().newXPath();
+
+            String expression = "/Tutorials/Tutorial";
+
+            nodeList = (NodeList) xPath.compile(expression).evaluate(xmlDocument, XPathConstants.NODESET);
+
+        } catch (SAXException | IOException | ParserConfigurationException | XPathExpressionException e) {
+            e.printStackTrace();
+        }
+        return nodeList;
+    }
+
+    public Node getNodeById(String id) {
+        Node node = null;
+        try {
+            DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
+
+            DocumentBuilder builder = builderFactory.newDocumentBuilder();
+
+            Document xmlDocument = builder.parse(this.getFile());
+
+            XPath xPath = XPathFactory.newInstance().newXPath();
+
+            String expression = "/Tutorials/Tutorial[@tutId=" + "'" + id + "'" + "]";
+
+            node = (Node) xPath.compile(expression).evaluate(xmlDocument, XPathConstants.NODE);
+
+        } catch (SAXException | IOException | ParserConfigurationException | XPathExpressionException e) {
+            e.printStackTrace();
+        }
+        return node;
+    }
+    
+    public NodeList getNodeListByTitle(String name) {
+        NodeList nodeList = null;
+        try {
+            DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
+
+            DocumentBuilder builder = builderFactory.newDocumentBuilder();
+
+            Document xmlDocument = builder.parse(this.getFile());
+
+            this.clean(xmlDocument);
+
+            XPath xPath = XPathFactory.newInstance().newXPath();
+
+            String expression = "//Tutorial[descendant::title[text()=" + "'" + name + "'" + "]]";
+
+            nodeList = (NodeList) xPath.compile(expression).evaluate(xmlDocument, XPathConstants.NODESET);
+
+        } catch (SAXException | IOException | ParserConfigurationException | XPathExpressionException e) {
+            e.printStackTrace();
+        }
+        return nodeList;
+    }
+
+    public NodeList getElementsByDate(String date) {
+        NodeList nodeList = null;
+
+        try {
+            DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
+
+            DocumentBuilder builder = builderFactory.newDocumentBuilder();
+
+            Document xmlDocument = builder.parse(this.getFile());
+
+            this.clean(xmlDocument);
+
+            XPath xPath = XPathFactory.newInstance().newXPath();
+
+            String expression = "//Tutorial[number(translate(date, '/', '')) > " + date + "]";
+
+            nodeList = (NodeList) xPath.compile(expression).evaluate(xmlDocument, XPathConstants.NODESET);
+
+        } catch (SAXException | IOException | ParserConfigurationException | XPathExpressionException e) {
+            e.printStackTrace();
+        }
+        return nodeList;
+    }
+
+    public NodeList getAllTutorials() {
+        NodeList nodeList = null;
+        try {
+            DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
+            builderFactory.setNamespaceAware(true);
+            DocumentBuilder builder = builderFactory.newDocumentBuilder();
+
+            Document xmlDocument = builder.parse(this.getFile());
+            
+            this.clean(xmlDocument);
+
+            XPath xPath = XPathFactory.newInstance().newXPath();
+            
+            xPath.setNamespaceContext(new NamespaceContext() {
+
+                @Override
+                public Iterator getPrefixes(String arg0) {
+                    return null;
+                }
+
+                @Override
+                public String getPrefix(String arg0) {
+                    return null;
+                }
+
+                @Override
+                public String getNamespaceURI(String arg0) {
+                    if ("bdn".equals(arg0)) {
+                        return "http://www.baeldung.com/full_archive";
+                    }
+                    return null;
+                }
+            });
+
+            String expression = "/bdn:Tutorials/bdn:Tutorial";
+
+            nodeList = (NodeList) xPath.compile(expression).evaluate(xmlDocument, XPathConstants.NODESET);
+
+        } catch (SAXException | IOException | ParserConfigurationException | XPathExpressionException e) {
+            e.printStackTrace();
+        }
+        return nodeList;
+    }
+
+    private void clean(Node node) {
+
+        NodeList childs = node.getChildNodes();
+
+        for (int n = childs.getLength() - 1; n >= 0; n--) {
+            Node child = childs.item(n);
+            short nodeType = child.getNodeType();
+
+            if (nodeType == Node.ELEMENT_NODE)
+                clean(child);
+            else if (nodeType == Node.TEXT_NODE) {
+                String trimmedNodeVal = child.getNodeValue().trim();
+                if (trimmedNodeVal.length() == 0)
+                    node.removeChild(child);
+                else
+                    child.setNodeValue(trimmedNodeVal);
+            } else if (nodeType == Node.COMMENT_NODE)
+                node.removeChild(child);
+        }
+    }
+
+    public File getFile() {
+        return file;
+    }
+
+    public void setFile(File file) {
+        this.file = file;
+    }
+
+}