JAVA操纵XML 实例讲解

JDBC开发中需要连接到不同的数据库，利用XML文件保存不同类型数据库的连接参数，并使用统一的程序解析XML以取得相应的连接参数。

<<Db.xml>><?xml version="1.0" encoding="UTF-8"?><DBS><DB><type>Oracle</type><driver>oracle.jdbc.driver.OracleDriver</driver><url>jdbc:oracle:thin:@localhost:1521:goudan</url><user>pubuser1</user><password>11111111</password></DB><DB><type>mysql</type><driver>org.git.mm.mysql.Driver</driver><url>jdbc:mysql://localhost:3306/BookDB</url><user>pubuser2</user><password>11111111</password></DB><DB><type>sqlserver</type><driver>com.microsoft.jdbc.sqlserver.SQLServerDriver</driver><url>jdbc:Microsoft:sqlserver://127.0.0.1:1433</url><user>pubuser3</user><password>11111111</password></DB></DBS><<DBTest.java>>package test.xml;import java.io.IOException;import javax.xml.parsers.DocumentBuilder;import javax.xml.parsers.DocumentBuilderFactory;import javax.xml.parsers.ParserConfigurationException;import org.w3c.dom.Document;import org.w3c.dom.Element;import org.w3c.dom.Node;import org.w3c.dom.NodeList;import org.xml.sax.SAXException;public class DBTest {public DBTest(String type) {// this.type = type ;DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();try {DocumentBuilder db = dbf.newDocumentBuilder();// 创建解析器Document doc = db.parse("Db.xml");// 解析地址NodeList n1 = doc.getElementsByTagName("DB");// 得到含有DB标签的一个列表for (int i = 0; i < n1.getLength(); i++) {Element myNode = (Element) n1.item(i);// 通过item方法获得每个对象if (myNode.getElementsByTagName("type").item(0).getFirstChild().getNodeValue().equals(type)) {String driver = myNode.getElementsByTagName("driver").item(0).getFirstChild().getNodeValue();String url = myNode.getElementsByTagName("url").item(0).getFirstChild().getNodeValue();String user = myNode.getElementsByTagName("user").item(0).getFirstChild().getNodeValue();String password = myNode.getElementsByTagName("password").item(0).getFirstChild().getNodeValue();System.out.println(driver + " " + url + " " + user + " "+ password);break;}}} catch (ParserConfigurationException e) {e.printStackTrace();} catch (SAXException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}public static void main(String[] rag) {DBTest dbt1 = new DBTest("Oracle");DBTest dbt2 = new DBTest("mysql");DBTest dbt3 = new DBTest("sqlserver");}}