TC java数据库访问标准格式(with transaction)

java 代码

 /**
  *
  * Get database connection from the db connection factory. It will set the connection to auto commit as required.
  * Note: autoCommit will be closed only for update statements, but not for query statements.
  *
  * @return A database connection.
  * @throws ChatContactPersistenceException
  *             If can't get connection or fails to set the auto commit value.
  */
 private Connection createConnection(boolean autoCommit) throws ChatContactPersistenceException {
     try {
         // create a DB connection
         Connection conn = connectionFactory.createConnection(connectionName);

         // Begin transaction.
         conn.setAutoCommit(autoCommit);

         return conn;
     } catch (DBConnectionException dbce) {
         throw new ChatContactPersistenceException("Can't get the connection from database.", dbce);
     } catch (SQLException sqle) {
         throw new ChatContactPersistenceException("Error while setting auto commit", sqle);
     }
 }

 /**
  *
  * Release the connection. If not success, rollback the transaction.
  *
  * @param conn
  *            the connection.
  * @param needRollBack
  *            whether rolling back is needed.
  */
 private void releaseConnection(Connection conn, boolean needRollBack) {
     try {
         if (needRollBack && (conn != null) && !conn.isClosed()) {
             conn.rollback();
         }
     } catch (SQLException e) {
         // ignore it
     }

     try {
         if ((conn != null) && !conn.isClosed()) {
             conn.close();
         }
     } catch (SQLException e) {
         // ignore it
     }
 }

 /**
  *
  * Release the statement and result set.
  *
  * @param stmt
  *            the statement to release
  * @param result
  *            the result to release
  */
 private void releaseStatement(Statement stmt, ResultSet result) {
     try {
         if (result != null) {
             result.close();
         }
         if (stmt != null) {
             stmt.close();
         }
     } catch (SQLException e) {
         // ignore it
     }
 }

public void addBuddy(long userId, long buddyUserId) throws Exception{
     Connection conn = null;
     boolean success = false;
     PreparedStatement stmt = null;

     try {
         // create a DB connection
         conn = createConnection(false);

         // Insert this buddy if not existed.
         stmt = conn.prepareStatement(SQL_INSERT_BUDDYUSER);
         stmt.setLong(1, userId);
         stmt.setLong(2, buddyUserId);
         stmt.executeUpdate();

         // commit the transaction
         conn.commit();
         success = true;
     } catch (SQLException sqle) {
         throw new ChatContactPersistenceException("Error while processing sql statement", sqle);
     } finally {
         releaseStatement(stmt, null);
         releaseConnection(conn, !success);
     }
 }