展示JDBC存取ORACLE大型数据对象LOB几种情况的示范类
import java.io.*; import java.util.*; import java.sql.*; public class LobPros{ /** * ORACLE驱动程序 */ private static final String DRIVER = "oracle.jdbc.driver.OracleDriver"; /** * ORACLE连接用URL */ private static final String URL = "jdbc:oracle:thin:@test2000:1521:orac"; /** * 用户名 */ private static final String USER = "user"; /** * 密码 */ private static final String PASSWORD = "pswd"; /** * 数据库连接 */ private static Connection conn = null; /** * SQL语句对象 */ private static Statement stmt = null; /** * @roseuid 3EDA089E02BC */ public LobPros() { } /** * 往数据库中插入一个新的CLOB对象 * * @param infile - 数据文件 * @throws java.lang.Exception * @roseuid 3EDA04A902BC */ public static void clobInsert(String infile) throws Exception { /* 设定不自动提交 */ boolean defaultCommit = conn.getAutoCommit(); conn.setAutoCommit(false); try { /* 插入一个空的CLOB对象 */ stmt.executeUpdate("INSERT INTO TEST_CLOB VALUES (''111'', EMPTY_CLOB())"); /* 查询此CLOB对象并锁定 */ ResultSet rs = stmt.executeQuery("SELECT CLOBCOL FROM TEST_CLOB WHERE ID=''111'' FOR UPDATE"); while (rs.next()) { /* 取出此CLOB对象 */ oracle.sql.CLOB clob = (oracle.sql.CLOB)rs.getClob("CLOBCOL"); /* 向CLOB对象中写入数据 */ BufferedWriter ut = new BufferedWriter(clob.getCharacterOutputStream()); BufferedReader in = new BufferedReader(new FileReader(infile)); int c; while ((c=in.read())!=-1) { out.write(c); } in.close(); out.close(); } /* 正式提交 */ conn.commit(); } catch (Exception ex) { /* 出错回滚 */ conn.rollback(); throw ex; } /* 恢复原提交状态 */ conn.setAutoCommit(defaultCommit); } /** * 修改CLOB对象（是在原CLOB对象基础上进行覆盖式的修改） * * @param infile - 数据文件 * @throws java.lang.Exception * @roseuid 3EDA04B60367 */ public static void clobModify(String infile) throws Exception { /* 设定不自动提交 */ boolean defaultCommit = conn.getAutoCommit(); conn.setAutoCommit(false); try { /* 查询CLOB对象并锁定 */ ResultSet rs = stmt.executeQuery("SELECT CLOBCOL FROM TEST_CLOB WHERE ID=''111'' FOR UPDATE"); while (rs.next()) { /* 获取此CLOB对象 */ oracle.sql.CLOB clob = (oracle.sql.CLOB)rs.getClob("CLOBCOL"); /* 进行覆盖式修改 */ BufferedWriter ut = new BufferedWriter(clob.getCharacterOutputStream()); BufferedReader in = new BufferedReader(new FileReader(infile)); int c; while ((c=in.read())!=-1) { out.write(c); } in.close(); out.close(); } /* 正式提交 */ conn.commit(); } catch (Exception ex) { /* 出错回滚 */ conn.rollback(); throw ex; } /* 恢复原提交状态 */ conn.setAutoCommit(defaultCommit); } /** * 替换CLOB对象（将原CLOB对象清除，换成一个全新的CLOB对象） * * @param infile - 数据文件 * @throws java.lang.Exception * @roseuid 3EDA04BF01E1 */ public static void clobReplace(String infile) throws Exception { /* 设定不自动提交 */ boolean defaultCommit = conn.getAutoCommit(); conn.setAutoCommit(false); try { /* 清空原CLOB对象 */ stmt.executeUpdate("UPDATE TEST_CLOB SET CLOBCOL=EMPTY_CLOB() WHERE ID=''111''"); /* 查询CLOB对象并锁定 */ ResultSet rs = stmt.executeQuery("SELECT CLOBCOL FROM TEST_CLOB WHERE ID=''111'' FOR UPDATE"); while (rs.next()) { /* 获取此CLOB对象 */ oracle.sql.CLOB clob = (oracle.sql.CLOB)rs.getClob("CLOBCOL"); /* 更新数据 */ BufferedWriter ut = new BufferedWriter(clob.getCharacterOutputStream()); BufferedReader in = new BufferedReader(new FileReader(infile)); int c; while ((c=in.read())!=-1) { out.write(c); } in.close(); out.close(); } /* 正式提交 */ conn.commit(); } catch (Exception ex) { /* 出错回滚 */ conn.rollback(); throw ex; } /* 恢复原提交状态 */ conn.setAutoCommit(defaultCommit); } /** * CLOB对象读取 * * @param outfile - 输出文件名 * @throws java.lang.Exception * @roseuid 3EDA04D80116 */ public static void clobRead(String outfile) throws Exception { /* 设定不自动提交 */ boolean defaultCommit = conn.getAutoCommit(); conn.setAutoCommit(false); try { /* 查询CLOB对象 */ ResultSet rs = stmt.executeQuery("SELECT * FROM TEST_CLOB WHERE ID=''111''"); while (rs.next()) { /* 获取CLOB对象 */ oracle.sql.CLOB clob = (oracle.sql.CLOB)rs.getClob("CLOBCOL"); /* 以字符形式输出 */ BufferedReader in = new BufferedReader(clob.getCharacterStream()); BufferedWriter ut = new BufferedWriter(new FileWriter(outfile)); int c; while ((c=in.read())!=-1) { out.write(c); } out.close(); in.close(); } } catch (Exception ex) { conn.rollback(); throw ex; } /* 恢复原提交状态 */ conn.setAutoCommit(defaultCommit); } /** * 向数据库中插入一个新的BLOB对象 * * @param infile - 数据文件 * @throws java.lang.Exception * @roseuid 3EDA04E300F6 */ public static void blobInsert(String infile) throws Exception { /* 设定不自动提交 */ boolean defaultCommit = conn.getAutoCommit(); conn.setAutoCommit(false); try { /* 插入一个空的BLOB对象 */ stmt.executeUpdate("INSERT INTO TEST_BLOB VALUES (''222'', EMPTY_BLOB())"); /* 查询此BLOB对象并锁定 */ ResultSet rs = stmt.executeQuery("SELECT BLOBCOL FROM TEST_BLOB WHERE ID=''222'' FOR UPDATE"); while (rs.next()) { /* 取出此BLOB对象 */ oracle.sql.BLOB blob = (oracle.sql.BLOB)rs.getBlob("BLOBCOL"); /* 向BLOB对象中写入数据 */ BufferedOutputStream ut = new BufferedOutputStream(blob.getBinaryOutputStream()); BufferedInputStream in = new BufferedInputStream(new FileInputStream(infile)); int c; while ((c=in.read())!=-1) { out.write(c); } in.close(); out.close(); } /* 正式提交 */ conn.commit(); } catch (Exception ex) { /* 出错回滚 */ conn.rollback(); throw ex; } /* 恢复原提交状态 */ conn.setAutoCommit(defaultCommit); } /** * 修改BLOB对象（是在原BLOB对象基础上进行覆盖式的修改） * * @param infile - 数据文件 * @throws java.lang.Exception * @roseuid 3EDA04E90106 */ public static void blobModify(String infile) throws Exception { /* 设定不自动提交 */ boolean defaultCommit = conn.getAutoCommit(); conn.setAutoCommit(false); try { /* 查询BLOB对象并锁定 */ ResultSet rs = stmt.executeQuery("SELECT BLOBCOL FROM TEST_BLOB WHERE ID=''222'' FOR UPDATE"); while (rs.next()) { /* 取出此BLOB对象 */ oracle.sql.BLOB blob = (oracle.sql.BLOB)rs.getBlob("BLOBCOL"); /* 向BLOB对象中写入数据 */ BufferedOutputStream ut = new BufferedOutputStream(blob.getBinaryOutputStream()); BufferedInputStream in = new BufferedInputStream(new FileInputStream(infile)); int c; while ((c=in.read())!=-1) { out.write(c); } in.close(); out.close(); } /* 正式提交 */ conn.commit(); } catch (Exception ex) { /* 出错回滚 */ conn.rollback(); throw ex; } /* 恢复原提交状态 */ conn.setAutoCommit(defaultCommit); } /** * 替换BLOB对象（将原BLOB对象清除，换成一个全新的BLOB对象） * * @param infile - 数据文件 * @throws java.lang.Exception * @roseuid 3EDA0505000C */ public static void blobReplace(String infile) throws Exception { /* 设定不自动提交 */ boolean defaultCommit = conn.getAutoCommit(); conn.setAutoCommit(false); try { /* 清空原BLOB对象 */ stmt.executeUpdate("UPDATE TEST_BLOB SET BLOBCOL=EMPTY_BLOB() WHERE ID=''222''"); /* 查询此BLOB对象并锁定 */ ResultSet rs = stmt.executeQuery("SELECT BLOBCOL FROM TEST_BLOB WHERE ID=''222'' FOR UPDATE"); while (rs.next()) { /* 取出此BLOB对象 */ oracle.sql.BLOB blob = (oracle.sql.BLOB)rs.getBlob("BLOBCOL"); /* 向BLOB对象中写入数据 */ BufferedOutputStream ut = new BufferedOutputStream(blob.getBinaryOutputStream()); BufferedInputStream in = new BufferedInputStream(new FileInputStream(infile)); int c; while ((c=in.read())!=-1) { out.write(c); } in.close(); out.close(); } /* 正式提交 */ conn.commit(); } catch (Exception ex) { /* 出错回滚 */ conn.rollback(); throw ex; } /* 恢复原提交状态 */ conn.setAutoCommit(defaultCommit); } /** * BLOB对象读取 * * @param outfile - 输出文件名 * @throws java.lang.Exception * @roseuid 3EDA050B003B */ public static void blobRead(String outfile) throws Exception { /* 设定不自动提交 */ boolean defaultCommit = conn.getAutoCommit(); conn.setAutoCommit(false); try { /* 查询BLOB对象 */ ResultSet rs = stmt.executeQuery("SELECT BLOBCOL FROM TEST_BLOB WHERE ID=''222''"); while (rs.next()) { /* 取出此BLOB对象 */ oracle.sql.BLOB blob = (oracle.sql.BLOB)rs.getBlob("BLOBCOL"); /* 以二进制形式输出 */ BufferedOutputStream ut = new BufferedOutputStream(new FileOutputStream(outfile)); BufferedInputStream in = new BufferedInputStream(blob.getBinaryStream()); int c; while ((c=in.read())!=-1) { out.write(c); } in.close(); out.close(); } /* 正式提交 */ conn.commit(); } catch (Exception ex) { /* 出错回滚 */ conn.rollback(); throw ex; } /* 恢复原提交状态 */ conn.setAutoCommit(defaultCommit); } /** * 建立测试用表格 * @throws Exception */ public static void createTables() throws Exception { try { stmt.executeUpdate("CREATE TABLE TEST_CLOB ( ID NUMBER(3), CLOBCOL CLOB)"); stmt.executeUpdate("CREATE TABLE TEST_BLOB ( ID NUMBER(3), BLOBCOL BLOB)"); } catch (Exception ex) { } } /** * @param args - 命令行参数 * @throws java.lang.Exception * @roseuid 3EDA052002AC */ public static void main(String[] args) throws Exception { /* 装载驱动,建立数据库连接 */ Class.forName(DRIVER); conn = DriverManager.getConnection(URL,USER,PASSWORD); stmt = conn.createStatement(); /* 建立测试表格 */ createTables(); /* CLOB对象插入测试 */ clobInsert("c:/clobInsert.txt"); clobRead("c:/clobInsert.out"); /* CLOB对象修改测试 */ clobModify("c:/clobModify.txt"); clobRead("c:/clobModify.out"); /* CLOB对象替换测试 */ clobReplace("c:/clobReplace.txt"); clobRead("c:/clobReplace.out"); /* BLOB对象插入测试 */ blobInsert("c:/blobInsert.doc"); blobRead("c:/blobInsert.out"); /* BLOB对象修改测试 */ blobModify("c:/blobModify.doc"); blobRead("c:/blobModify.out"); /* BLOB对象替换测试 */ blobReplace("c:/blobReplace.doc"); blobRead("c:/bolbReplace.out"); /* 关闭资源退出 */ conn.close(); System.exit(0); }}
启程了，人的智慧才得以发挥。
