jdbcutils.java

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		else if (obj instanceof Clob) {
			obj = rs.getString(index);
		}
		else if (obj != null && obj.getClass().getName().startsWith("oracle.sql.TIMESTAMP")) {
			obj = rs.getTimestamp(index);
		}
		else if (obj != null && obj.getClass().getName().startsWith("oracle.sql.DATE")) {
			String metaDataClassName = rs.getMetaData().getColumnClassName(index);
			if ("java.sql.Timestamp".equals(metaDataClassName) ||
					"oracle.sql.TIMESTAMP".equals(metaDataClassName)) {
				obj = rs.getTimestamp(index);
			}
			else {
				obj = rs.getDate(index);
			}
		}
		else if (obj != null && obj instanceof java.sql.Date) {
			if ("java.sql.Timestamp".equals(rs.getMetaData().getColumnClassName(index))) {
				obj = rs.getTimestamp(index);
			}
		}
		return obj;
	}

	/**
	 * Extract database meta data via the given DatabaseMetaDataCallback.
	 * <p>This method will open a connection to the database and retrieve the database metadata.
	 * Since this method is called before the exception translation feature is configured for
	 * a datasource, this method can not rely on the SQLException translation functionality.
	 * <p>Any exceptions will be wrapped in a MetaDataAccessException. This is a checked exception
	 * and any calling code should catch and handle this exception. You can just log the
	 * error and hope for the best, but there is probably a more serious error that will
	 * reappear when you try to access the database again.
	 * @param dataSource the DataSource to extract metadata for
	 * @param action callback that will do the actual work
	 * @return object containing the extracted information, as returned by
	 * the DatabaseMetaDataCallback's <code>processMetaData</code> method
	 * @throws MetaDataAccessException if meta data access failed
	 */
	public static Object extractDatabaseMetaData(DataSource dataSource, DatabaseMetaDataCallback action)
			throws MetaDataAccessException {

		Connection con = null;
		try {
			con = DataSourceUtils.getConnection(dataSource);
			if (con == null) {
				// should only happen in test environments
				throw new MetaDataAccessException("Connection returned by DataSource [" + dataSource + "] was null");
			}
			DatabaseMetaData metaData = con.getMetaData();
			if (metaData == null) {
				// should only happen in test environments
				throw new MetaDataAccessException("DatabaseMetaData returned by Connection [" + con + "] was null");
			}
			return action.processMetaData(metaData);
		}
		catch (CannotGetJdbcConnectionException ex) {
			throw new MetaDataAccessException("Could not get Connection for extracting meta data", ex);
		}
		catch (SQLException ex) {
			throw new MetaDataAccessException("Error while extracting DatabaseMetaData", ex);
		}
		catch (AbstractMethodError err) {
			throw new MetaDataAccessException(
					"JDBC DatabaseMetaData method not implemented by JDBC driver - upgrade your driver", err);
		}
		finally {
			DataSourceUtils.releaseConnection(con, dataSource);
		}
	}

	/**
	 * Call the specified method on DatabaseMetaData for the given DataSource,
	 * and extract the invocation result.
	 * @param dataSource the DataSource to extract meta data for
	 * @param metaDataMethodName the name of the DatabaseMetaData method to call
	 * @return the object returned by the specified DatabaseMetaData method
	 * @throws MetaDataAccessException if we couldn't access the DatabaseMetaData
	 * or failed to invoke the specified method
	 * @see java.sql.DatabaseMetaData
	 */
	public static Object extractDatabaseMetaData(DataSource dataSource, final String metaDataMethodName)
			throws MetaDataAccessException {

		return extractDatabaseMetaData(dataSource,
				new DatabaseMetaDataCallback() {
					public Object processMetaData(DatabaseMetaData dbmd) throws SQLException, MetaDataAccessException {
						try {
							Method method = DatabaseMetaData.class.getMethod(metaDataMethodName, (Class[]) null);
							return method.invoke(dbmd, (Object[]) null);
						}
						catch (NoSuchMethodException ex) {
							throw new MetaDataAccessException("No method named '" + metaDataMethodName +
									"' found on DatabaseMetaData instance [" + dbmd + "]", ex);
						}
						catch (IllegalAccessException ex) {
							throw new MetaDataAccessException(
									"Could not access DatabaseMetaData method '" + metaDataMethodName + "'", ex);
						}
						catch (InvocationTargetException ex) {
							if (ex.getTargetException() instanceof SQLException) {
								throw (SQLException) ex.getTargetException();
							}
							throw new MetaDataAccessException(
									"Invocation of DatabaseMetaData method '" + metaDataMethodName + "' failed", ex);
						}
					}
				});
	}

	/**
	 * Return whether the given JDBC driver supports JDBC 2.0 batch updates.
	 * <p>Typically invoked right before execution of a given set of statements:
	 * to decide whether the set of SQL statements should be executed through
	 * the JDBC 2.0 batch mechanism or simply in a traditional one-by-one fashion.
	 * <p>Logs a warning if the "supportsBatchUpdates" methods throws an exception
	 * and simply returns <code>false</code> in that case.
	 * @param con the Connection to check
	 * @return whether JDBC 2.0 batch updates are supported
	 * @see java.sql.DatabaseMetaData#supportsBatchUpdates()
	 */
	public static boolean supportsBatchUpdates(Connection con) {
		try {
			DatabaseMetaData dbmd = con.getMetaData();
			if (dbmd != null) {
				if (dbmd.supportsBatchUpdates()) {
					logger.debug("JDBC driver supports batch updates");
					return true;
				}
				else {
					logger.debug("JDBC driver does not support batch updates");
				}
			}
		}
		catch (SQLException ex) {
			logger.debug("JDBC driver 'supportsBatchUpdates' method threw exception", ex);
		}
		catch (AbstractMethodError err) {
			logger.debug("JDBC driver does not support JDBC 2.0 'supportsBatchUpdates' method", err);
		}
		return false;
	}

	/**
	 * Extract a common name for the database in use even if various drivers/platforms provide varying names.
	 * @param source the name as provided in database metedata
	 * @return the common name to be used
	 */
	public static String commonDatabaseName(String source) {
		String name = source;
		if (source != null && source.startsWith("DB2")) {
			name = "DB2";
		}
		else if ("Sybase SQL Server".equals(source) ||
				"Adaptive Server Enterprise".equals(source) || "sql server".equals(source) ) {
			name = "Sybase";
		}
		return name;
	}

	/**
	 * Check whether the given SQL type is numeric.
	 * @param sqlType the SQL type to be checked
	 * @return whether the type is numeric
	 */
	public static boolean isNumeric(int sqlType) {
		return Types.BIT == sqlType || Types.BIGINT == sqlType || Types.DECIMAL == sqlType ||
				Types.DOUBLE == sqlType || Types.FLOAT == sqlType || Types.INTEGER == sqlType ||
				Types.NUMERIC == sqlType || Types.REAL == sqlType || Types.SMALLINT == sqlType ||
				Types.TINYINT == sqlType;
	}

	/**
	 * Determine the column name to use. The column name is determined based on a
	 * lookup using ResultSetMetaData.
	 * <p>This method implementation takes into account recent clarifications
	 * expressed in the JDBC 4.0 specification:
	 * <p><i>columnLabel - the label for the column specified with the SQL AS clause.
	 * If the SQL AS clause was not specified, then the label is the name of the column</i>.
	 * @return the column name to use
	 * @param resultSetMetaData the current meta data to use
	 * @param columnIndex the index of the column for the look up
	 * @throws SQLException in case of lookup failure
	 */
	public static String lookupColumnName(ResultSetMetaData resultSetMetaData, int columnIndex) throws SQLException {
		String name = resultSetMetaData.getColumnLabel(columnIndex);
		if (name == null || name.length() < 1) {
			name = resultSetMetaData.getColumnName(columnIndex);
		}
		return name;
	}

	/**
	 * Convert a column name with underscores to the corresponding property name using "camel case".  A name
	 * like "customer_number" would match a "customerNumber" property name.
	 * @param name the column name to be converted
	 * @return the name using "camel case"
	 */
	public static String convertUnderscoreNameToPropertyName(String name) {
		StringBuffer result = new StringBuffer();
		boolean nextIsUpper = false;
		if (name != null && name.length() > 0) {
			if (name.length() > 1 && name.substring(1,2).equals("_")) {
				result.append(name.substring(0, 1).toUpperCase());
			}
			else {
				result.append(name.substring(0, 1).toLowerCase());
			}
			for (int i = 1; i < name.length(); i++) {
				String s = name.substring(i, i + 1);
				if (s.equals("_")) {
					nextIsUpper = true;
				}
				else {
					if (nextIsUpper) {
						result.append(s.toUpperCase());
						nextIsUpper = false;
					}
					else {
						result.append(s.toLowerCase());
					}
				}
			}
		}
		return result.toString();
	}

}