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clob保存为本地xml文件,修改后上传
这两天与小伙伴写了一个小程序,实现的功能如下:
首先将数据库的clob保存为本地的xml文件,然后对xml进行修改后上传至数据库
主要的难点如下:
1:clob文件的下载与上传,其中保存为本地的文件要求是UTF-8格式
2:xml文件中节点的修改
clob的上传与下载如下
import java.io.BufferedReader; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStreamReader; import java.io.OutputStreamWriter; import java.io.Reader; import java.io.UnsupportedEncodingException; import java.sql.Clob; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; /** * @author GuoDi-CT DC * */ public class ClobModify { /** *@param id 数据库中的ID * 返回 保存文件的绝对路径 */ public static String ClobToXml(int id) { Connection conn = DB.getConn(); Statement stmt = DB.createStmt(conn); String sql = "select * from BD_PROCESS_DEF_VER where ID =" + id; ResultSet rs = DB.getRs(stmt, sql); String xmlFile = null; try { if (rs.next()) { int fjbh = rs.getInt(1); xmlFile = "d:\\xml\\" + fjbh + ".xml"; Clob clob = rs.getClob(16); FileOutputStream fo = new FileOutputStream(xmlFile); OutputStreamWriter so = new OutputStreamWriter(fo, "UTF-8"); if (clob != null) { Reader is = clob.getCharacterStream(); BufferedReader br = new BufferedReader(is); String s = br.readLine(); while (s != null) { so.write(s + System.getProperty("line.separator")); // System.out.println(str); s = br.readLine(); } } so.flush(); so.close(); } } catch (SQLException | IOException e) { e.printStackTrace(); } DB.close(rs); DB.close(stmt); DB.close(conn); return xmlFile; } public static void updateClob(String fileName, int id) { FileInputStream fis = null; InputStreamReader rd = null; try { fis = new FileInputStream(fileName); rd = new InputStreamReader(fis, "UTF-8"); } catch (FileNotFoundException e2) { e2.printStackTrace(); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } PreparedStatement pst = null; Connection conn = DB.getConn(); Statement stmt = DB.createStmt(conn); try { conn.setAutoCommit(false); } catch (SQLException e1) { e1.printStackTrace(); } String sql1 = "update BD_PROCESS_DEF_VER s set s.NODE_INFO=' ' where ID=" + id; // 这边需要设置一个空的字段,后面就不会出现空指针 try { stmt.execute(sql1); } catch (SQLException e) { e.printStackTrace(); } String sql2 = "select * from BD_PROCESS_DEF_VER s where s.ID=" + id; // 锁定数据行进行更新,注意“for update”语句 ResultSet rs = null; try { rs = stmt.executeQuery(sql2); } catch (SQLException e) { e.printStackTrace(); } try { while (rs.next()) { String sql3 = "update BD_PROCESS_DEF_VER set NODE_INFO= ? where ID="+ id; pst = conn.prepareStatement(sql3); pst.setCharacterStream(1, rd, 100000000); pst.executeUpdate(); } // 最后一步自己提交 conn.commit(); conn.setAutoCommit(true); } catch (SQLException e) { e.printStackTrace(); } finally { DB.close(rs); DB.close(stmt); try { pst.close(); } catch (SQLException e) { e.printStackTrace(); } DB.close(conn); } } }
其中DB是连接数据库的javabean,如下
import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; /** * @author GuoDi-CT DC * jdcbc JavaBean * */ public class DB { // 驱动程序就是之前在classpath中配置的JDBC的驱动程序的JAR 包中 public static final String DBDRIVER = "oracle.jdbc.driver.OracleDriver"; // 连接地址是由各个数据库生产商单独提供的,所以需要单独记住 public static final String DBURL = "jdbc:oracle:thin:@172.17.20.215:1521:BPMIDE"; // 连接数据库的用户名 public static final String DBUSER = "bpmduser"; // 连接数据库的密码 public static final String DBPASS = "bpmd"; public static Connection getConn() { Connection conn = null; try { Class.forName(DBDRIVER); conn = DriverManager.getConnection(DBURL, DBUSER, DBPASS); // 2、连接数据库 } catch (ClassNotFoundException e) { e.printStackTrace(); } // 1、使用CLASS 类加载驱动程序 catch (SQLException e) { e.printStackTrace(); } return conn; } public static Statement createStmt(Connection conn) { Statement stmt = null; try { stmt = conn.createStatement(); } catch (SQLException e) { e.printStackTrace(); } return stmt; } public static ResultSet getRs(Statement stmt, String sql) { ResultSet rs = null; try { rs = stmt.executeQuery(sql); } catch (SQLException e) { e.printStackTrace(); } return rs; } public static void close(ResultSet rs) { if (rs != null) { try { rs.close(); } catch (SQLException e) { e.printStackTrace(); } finally { rs = null; } } } public static void close(Statement stmt) { if (stmt != null) { try { stmt.close(); } catch (SQLException e) { e.printStackTrace(); } finally { stmt = null; } } } public static void close(Connection conn) { if (conn != null) { try { conn.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } finally { conn = null; } } } }
xml的修改程序如下
import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import javax.xml.transform.OutputKeys; import javax.xml.transform.Transformer; import javax.xml.transform.TransformerFactory; import javax.xml.transform.dom.DOMSource; import javax.xml.transform.stream.StreamResult; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.NodeList; import org.xml.sax.SAXException; /** * * @author zhangwen.ctdc DOM更新与解析XML文档 */ public class XmlAnalysis /* implements XmlDocumentInterface */{ private Document document; public void init() { try { DocumentBuilderFactory factory = DocumentBuilderFactory .newInstance(); DocumentBuilder builder = factory.newDocumentBuilder(); this.document = builder.newDocument(); } catch (ParserConfigurationException e) { System.out.println(e.getMessage()); } } public void insertElementNode(String fileName, String nodeName, String newElementName) { document = parserXml(fileName); NodeList nodeList = document.getElementsByTagName(nodeName); for (int i = 0; i < nodeList.getLength(); i++) { Element element = document.createElement(newElementName); nodeList.item(i).appendChild(element); } createXml(fileName); } public void insertAttrNode(String fileName, String nodeName, String newAttrName, String attrValue) { document = parserXml(fileName); NodeList nodeList = document.getElementsByTagName(nodeName); for (int i = 0; i < nodeList.getLength(); i++) { Element element = (Element) (nodeList.item(i)); element.setAttribute(newAttrName, attrValue); } createXml(fileName); } public void insertTextNode(String fileName, String nodeName, String textNode) { document = parserXml(fileName); NodeList nodeList = document.getElementsByTagName(nodeName); for (int i = 0; i < nodeList.getLength(); i++) { nodeList.item(i).appendChild(document.createTextNode(textNode)); } createXml(fileName); } public void deleteElementNode(String fileName, String nodeName) { document = parserXml(fileName); NodeList nodeList = document.getElementsByTagName(nodeName); while (nodeList.getLength() > 0) { nodeList.item(0).getParentNode().removeChild(nodeList.item(0)); nodeList = document.getElementsByTagName(nodeName); } createXml(fileName); } public void updateNode(String fileName, String nodeName, String attrName, String newAttrValue) { document = parserXml(fileName); NodeList nodeList = document.getElementsByTagName(nodeName); for (int i = 0; i < nodeList.getLength(); i++) { Element node = (Element) nodeList.item(i); node.setAttribute(attrName, newAttrValue); } createXml(fileName); } private Document parserXml(String fileName) { try { DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); DocumentBuilder db = dbf.newDocumentBuilder(); Document document = db.parse(fileName); System.out.println("-----------------------------------" + "解析完毕" + "----------------------------------------"); return document; } catch (FileNotFoundException e) { System.out.println(e.getMessage()); } catch (ParserConfigurationException e) { System.out.println(e.getMessage()); } catch (SAXException e) { System.out.println(e.getMessage()); } catch (IOException e) { System.out.println(e.getMessage()); } return document; } private void createXml(String fileName) { try { /** 将document中的内容写入文件中 */ TransformerFactory tFactory = TransformerFactory.newInstance(); Transformer transformer = tFactory.newTransformer(); transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8"); transformer.setOutputProperty(OutputKeys.INDENT, "yes"); DOMSource source = new DOMSource(document); StreamResult result = new StreamResult(new FileOutputStream( fileName)); transformer.transform(source, result); System.out.println("--------------------------------" + "更新 XML文件成功" + "-------------------------------------"); } catch (Exception exception) { System.out.println("更新" + fileName + "出错:" + exception); exception.printStackTrace(); } } }
最后程序提供的接口与说明如下
/** * @author GuoDi and ZhangWen * */ public interface NodeInfoInterface { /** * XML文档 插元素入节点 * @param time 时间 * @param nodeName 标签名 * @param newElementName 新标签 */ public void insertElementNode(String time, String nodeName,String newElementName); /** * @param time 时间 * @param nodeName 标签名 * @param newAttrName 新属性名 * @param attrValue 新属性值 * XML文档 插入属性节点 */ public void insertAttrNode(String time,String nodeName,String newAttrName,String attrValue); /** * @param time 时间 * @param nodeName 标签名 * @param textNode 文本 * XML文档 插入文本节点 */ public void insertTextNode(String time,String nodeName,String textNode); /** * @param time 时间 * @param nodeName 标签名 * XML文档 删除所有对应元素节点 */ public void deleteElementNode(String time,String nodeName); /** * @param time 时间 * @param nodeName 标签名 * @param newAttrName 新属性名 * @param attrValue 新属性值 * XML文档 修改属性节点内容 */ public void updateNode(String time,String nodeName,String newAttrName,String attrValue); }
clob保存为本地xml文件,修改后上传
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