DOM的概念和簡單應用：使用DOM解析XML數據
阿新 • • 發佈：2017-05-22
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概念：DOM是Document Object Model的簡稱，即文檔數據模型。
Oracle公司提供了JAXP（Java API for XML Processing）來解析XML。JAXP會把XML文檔轉換成一個DOM樹，JAXP的三個包都在JDK中。
org.w3c.dom;W3C推薦的解析文檔的接口
org.xml.sax;使用SAX解析XML文檔的接口
javax.xml.parsers;解析器工廠工具
一、使用DOM解析XML文檔的步驟
1.創建解析器工廠對象，即DocumentBuilderFactory對象
2.由解析器工廠創建解析器對象，即DocumentBuilder對象
3.由解析器對象解析XML文檔構建相應的DOM樹，創建Document對象
4.以Document對象為起點對DOM樹的節點進行增加、刪除、修改、查詢等操作
5.保存XML數據文檔
二、案例
1 <?xml version="1.0" encoding="GB2312" standalone="no"?> 2 <PhoneInfo> 3 <Brand name="華為"> 4 <Type name="P9" /> 5 <Item> 6 <title>標題信息</title> 7 <link>連接</link> 8 <description>描述</description> 9 <pubDate>2016-11-12</pubDate> 10 </Item> 11 </Brand> 12 <Brand name="蘋果"> 13 <Type name="iPhone5" /> 14 <Type name="iPhone6" /> 15 </Brand> 16 <Brand name="SAMSUNG"> 17 <Type name="Note7" /> 18 </Brand> 19 <Brand name="SAMSUNG"> 20 <Type name="Note7" /> 21 </Brand> 22 <Brand name="三星"> 23 <Type name="Note7" /> 24 </Brand> 25 <Brand name="三星"> 26 <Type name="Note7" /> 27 </Brand> 28 </PhoneInfo>
1.使用DOM讀取手機收藏信息
1 import java.io.IOException; 2 3 import javax.xml.parsers.DocumentBuilder; 4 import javax.xml.parsers.DocumentBuilderFactory; 5 import javax.xml.parsers.ParserConfigurationException; 6 7 import org.w3c.dom.Document; 8 import org.w3c.dom.Element; 9 import org.w3c.dom.Node; 10 import org.w3c.dom.NodeList; 11 import org.xml.sax.SAXException; 12 13 /** 14 * DOM解析xml文檔 15 * @author Administrator 16 * 17 */ 18 public class PhoneInfoShow { 19 20 public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException{ 21 //得到DOM解析器的工廠實例 22 DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); 23 //從DOM工廠獲得DOM解析器 24 DocumentBuilder builder = dbf.newDocumentBuilder(); 25 //解析xml文檔，得到一個Document對象，即DOM樹 26 Document phoneInfo = builder.parse("src/PhoneInfo.xml"); 27 //得到所有Brand節點列表信息 28 NodeList brandList = phoneInfo.getElementsByTagName("Brand"); 29 //循環Brand信息 30 for (int i = 0; i < brandList.getLength(); i++) { 31 //獲取第i個Brand元素信息 32 Node node = brandList.item(i); 33 Element brand = (Element)node; 34 //獲取元素屬性值 35 String brandValue = brand.getAttribute("name"); 36 System.out.println("手機品牌："+brandValue); 37 //獲取brand元素下的所有子元素 38 NodeList types = brand.getElementsByTagName("Type"); 39 for (int j = 0; j < types.getLength(); j++) { 40 /*Node item = types.item(j); 41 Element type = (Element)item;*/ 42 Element type = (Element)types.item(j); 43 //獲取子節點屬性值 44 String typeValue = type.getAttribute("name"); 45 System.out.println("\t型號："+typeValue); 46 } 47 } 48 } 49 50 }
2.查找節點信息
1 /** 2 * 查找節點信息 3 * @author Administrator 4 * 5 */ 6 public class PhoneInfo03{ 7 8 public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException { 9 //得到DOM解析器工廠 10 DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); 11 //從DOM工廠獲得DOM解析器 12 DocumentBuilder db = dbf.newDocumentBuilder(); 13 //解析XML文檔得到一個DOM樹 14 Document phoneInfo = db.parse(new File("src/PhoneInfo.xml")); 15 //讀取pubDate 16 NodeList list = phoneInfo.getElementsByTagName("pubDate"); 17 //pubDate元素節點（轉換） 18 Element pubDateElement = (Element)list.item(0); 19 //讀取文本節點 20 String pubDate = pubDateElement.getFirstChild().getNodeValue(); 21 System.out.println(pubDate); 22 } 23 24 }
三、使用DOM維護XML數據
1.添加信息
1 import java.io.FileOutputStream; 2 import java.io.IOException; 3 4 import javax.xml.parsers.DocumentBuilder; 5 import javax.xml.parsers.DocumentBuilderFactory; 6 import javax.xml.parsers.ParserConfigurationException; 7 import javax.xml.transform.OutputKeys; 8 import javax.xml.transform.Transformer; 9 import javax.xml.transform.TransformerException; 10 import javax.xml.transform.TransformerFactory; 11 import javax.xml.transform.dom.DOMSource; 12 import javax.xml.transform.stream.StreamResult; 13 14 import org.w3c.dom.Document; 15 import org.w3c.dom.Element; 16 import org.xml.sax.SAXException; 17 18 /** 19 * 添加手機收藏信息 20 * @author Administrator 21 * 22 */ 23 public class PhoneInfoAdd { 24 25 public static void main(String[] args) throws TransformerException, SAXException, IOException, ParserConfigurationException { 26 //解析器工廠 27 DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); 28 //解析器 29 DocumentBuilder db = dbf.newDocumentBuilder(); 30 //DOM文檔 31 Document phone = db.parse("src/PhoneInfo.xml"); 32 /*創建brand節點*/ 33 Element brand = phone.createElement("Brand"); 34 brand.setAttribute("name","三星"); 35 /*創建type節點*/ 36 Element type = phone.createElement("Type"); 37 type.setAttribute("name", "Note7"); 38 //建立父子關系 39 brand.appendChild(type); 40 Element phoneElement = (Element)phone.getElementsByTagName("PhoneInfo").item(0); 41 phoneElement.appendChild(brand); 42 43 //保存xml文件 44 /*使用傳輸工廠*/ 45 TransformerFactory transformerFactory = TransformerFactory.newInstance(); 46 Transformer transformer = transformerFactory.newTransformer(); 47 /*創建數據源*/ 48 DOMSource domSource = new DOMSource(phone); 49 /*設置編碼類型*/ 50 transformer.setOutputProperty(OutputKeys.ENCODING, "gb2312"); 51 /*創建目標數據*/ 52 StreamResult result = new StreamResult(new FileOutputStream("src/PhoneInfo.xml")); 53 /*把DOM樹轉換為xml文件*/ 54 transformer.transform(domSource, result); 55 56 } 57 58 }
2.修改信息
1 import java.io.FileOutputStream; 2 import java.io.IOException; 3 4 import javax.xml.parsers.DocumentBuilder; 5 import javax.xml.parsers.DocumentBuilderFactory; 6 import javax.xml.parsers.ParserConfigurationException; 7 import javax.xml.transform.OutputKeys; 8 import javax.xml.transform.Result; 9 import javax.xml.transform.Transformer; 10 import javax.xml.transform.TransformerException; 11 import javax.xml.transform.TransformerFactory; 12 import javax.xml.transform.dom.DOMSource; 13 import javax.xml.transform.stream.StreamResult; 14 15 import org.w3c.dom.Document; 16 import org.w3c.dom.Element; 17 import org.w3c.dom.NodeList; 18 import org.xml.sax.SAXException; 19 20 public class PhoneInfoEdit { 21 22 public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException, TransformerException { 23 //解析xml得到DOM對象 24 DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); 25 DocumentBuilder db = dbf.newDocumentBuilder(); 26 Document phone = db.parse("src/PhoneInfo.xml"); 27 //找到修改的菜單 28 NodeList brand = phone.getElementsByTagName("Brand"); 29 for (int i = 0; i < brand.getLength(); i++) { 30 Element brandElement = (Element)brand.item(i); 31 //得到Brand的name屬性 32 String brandName = brandElement.getAttribute("name"); 33 if ("三星".equals(brandName)) { 34 brandElement.setAttribute("name","SAMSUNG"); 35 } 36 } 37 //保存xml文件 38 TransformerFactory transformerFactory = TransformerFactory.newInstance(); 39 Transformer transformer = transformerFactory.newTransformer(); 40 /*創建DOM源*/ 41 DOMSource xmlSource = new DOMSource(phone); 42 /*設置編碼類型*/ 43 transformer.setOutputProperty(OutputKeys.ENCODING,"gb2312"); 44 Result outputTarget = new StreamResult(new FileOutputStream("src/PhoneInfo.xml")); 45 //寫入文件 46 transformer.transform(xmlSource, outputTarget ); 47 } 48 49 }
3.刪除信息
1 import java.io.FileOutputStream; 2 import java.io.IOException; 3 4 import javax.xml.parsers.DocumentBuilder; 5 import javax.xml.parsers.DocumentBuilderFactory; 6 import javax.xml.parsers.ParserConfigurationException; 7 import javax.xml.transform.OutputKeys; 8 import javax.xml.transform.Result; 9 import javax.xml.transform.Transformer; 10 import javax.xml.transform.TransformerException; 11 import javax.xml.transform.TransformerFactory; 12 import javax.xml.transform.dom.DOMSource; 13 import javax.xml.transform.stream.StreamResult; 14 15 import org.w3c.dom.Document; 16 import org.w3c.dom.Element; 17 import org.w3c.dom.NodeList; 18 import org.xml.sax.SAXException; 19 20 /** 21 * 刪除節點 22 * @author Administrator 23 * 24 */ 25 public class PhoneInfoDel { 26 27 public static void main(String[] args) throws SAXException, IOException, ParserConfigurationException, TransformerException { 28 //解析xml文檔 29 DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance(); 30 DocumentBuilder documentBuilder = builderFactory.newDocumentBuilder(); 31 Document phone = documentBuilder.parse("src/PhoneInfo.xml"); 32 //找到要刪除的節點 33 NodeList brand = phone.getElementsByTagName("Brand"); 34 //通過遍歷Brand找到要刪除的節點 35 for (int i = 0; i < brand.getLength(); i++) { 36 Element brandElement = (Element)brand.item(i); 37 //獲取Brand節點屬性 38 String brandName = brandElement.getAttribute("name"); 39 //查找需要的節點 40 if ("SAMSUNG".equals(brandName)) { 41 //獲取父節點，利用父節點刪除這個節點 42 brandElement.getParentNode().removeChild(brandElement); 43 } 44 } 45 /*for (int i = 0; i < brand.getLength(); i++) { 46 Element brandElement = (Element)brand.item(i); 47 //得到Brand的name屬性 48 String brandName = brandElement.getAttribute("name"); 49 if ("三星".equals(brandName)) { 50 //修改屬性 51 brandElement.setAttribute("name","SAMSUNG"); 52 //獲取父節點，利用父節點刪除這個節點 53 brandElement.getParentNode().removeChild(brandElement); 54 } 55 }*/ 56 //寫入xml 57 TransformerFactory transformerFactory = TransformerFactory.newInstance(); 58 Transformer transformer = transformerFactory.newTransformer(); 59 DOMSource xmlSource = new DOMSource(phone); 60 //設置編碼 61 transformer.setOutputProperty(OutputKeys.ENCODING,"gb2312"); 62 Result outputTarget = new StreamResult(new FileOutputStream("src/PhoneInfo.xml")); 63 transformer.transform(xmlSource, outputTarget); 64 /*TransformerFactory transformerFactory = TransformerFactory.newInstance(); 65 Transformer transformer = transformerFactory.newTransformer(); 66 創建DOM源 67 DOMSource xmlSource = new DOMSource(phone); 68 設置編碼類型 69 transformer.setOutputProperty(OutputKeys.ENCODING,"gb2312"); 70 Result outputTarget = new StreamResult(new FileOutputStream("src/PhoneInfo.xml")); 71 //寫入文件 72 transformer.transform(xmlSource, outputTarget );*/ 73 74 } 75 76 }
此外，還可以使用DOM4J解析XML文檔會更加方便。
DOM的概念和簡單應用：使用DOM解析XML數據