MVCDemoMVC的java版简单实例

package M; import java.io.File; import java.io.IOException; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; 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 OracleConnect { public Connection con = null;// 创建一个数据库连接 public PreparedStatement pre = null;// 创建预编译语句对象，一般都是用这个而不用Statement public ResultSet result = null ;// 创建一个结果集对象 private String Driver = ""; private String url = ""; public OracleConnect(String user, String pssword){ getConfig(); connect(user,pssword); } private void getConfig() { try { //1。获取DOM 解析器的工厂实例。 DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); //2。获得具体的DOM解析器。 DocumentBuilder builder = factory.newDocumentBuilder(); //3。获取文件 Document document = builder.parse(new File("src/M/DBconfig.xml")); //4。获取根元素 Element root = document.getDocumentElement(); //5。获取根节点[有多个节点] NodeList list = root.getElementsByTagName("connect"); for (int i = 0; i < list.getLength(); i++) { Element lan = (Element) list.item(i); NodeList clist = lan.getChildNodes(); for (int j = 0; j < clist.getLength(); j++) { Node c = clist.item(j); if (c instanceof Element) { if(c.getNodeName() == "driver"){ this.Driver = c.getTextContent(); } if(c.getNodeName() == "url"){ this.url = c.getTextContent(); } } } } } catch (ParserConfigurationException e) { e.printStackTrace(); } catch (SAXException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } public void connect(String user ,String password){ try { Class.forName(Driver);// 加载数据库驱动程序 System.out.println("开始尝试连接数据库！"); con = DriverManager.getConnection(url, user, password);// 获取连接 System.out.println("数据库连接成功！"); } catch (Exception e) { System.out.println("数据库连接失败！"); } } public void close(){ try { if(result!=null) result.close(); if(pre!=null) pre.close(); if(con!=null) con.close(); System.out.println("数据库连接已关闭！"); } catch (Exception e) { System.out.println("数据库连接关闭失败！"); } } public void insert(String sql){ try{ pre = con.prepareStatement(sql); }catch(Exception e){ System.out.println("插入异常！"); } } public void delete(String sql){ try{ pre = con.prepareStatement(sql); }catch(Exception e){ System.out.println("删除异常!"); } } public void update(String sql){ try{ pre = con.prepareStatement(sql); }catch(Exception e){ System.out.println("修改异常！"); } } public ResultSet query(String sql){ try{ pre = con.prepareStatement(sql); result = pre.executeQuery(); }catch(Exception e){ System.out.println("查询异常！"); } return result; } }