connection.java

网上销售系统是目前 Internet 上广泛使用的在线系统之一。 网上售书这是信息社会发展的必然要求。国际互联网的开通

        } else if (host.indexOf(",") != -1) {
            // multiple hosts separated by commas (failover)
            hostList = StringUtils.split(host, ",", true);
        } else {
            this.host = host;
            hostList = new ArrayList();
            hostList.add(this.host);
        }

        hostListSize = hostList.size();
        this.port = port;

        if (database == null) {
            throw new SQLException("Malformed URL '" + url + "'.",
                SQLError.SQL_STATE_GENERAL_ERROR);
        }

        this.database = database;
        this.myURL = url;
        this.myDriver = d;
        this.user = info.getProperty("user");
        this.password = info.getProperty("password");

        if ((this.user == null) || this.user.equals("")) {
            this.user = "nobody";
        }

        if (this.password == null) {
            this.password = "";
        }

        this.props = info;
        initializeDriverProperties(info);

        if (Driver.DEBUG) {
            System.out.println("Connect: " + this.user + " to " + this.database);
        }

        try {
            createNewIO(false);
            this.dbmd = new DatabaseMetaData(this, this.database);
        } catch (java.sql.SQLException ex) {
            cleanup(ex);

            // don't clobber SQL exceptions
            throw ex;
        } catch (Exception ex) {
            cleanup(ex);

            StringBuffer mesg = new StringBuffer();

            if (!useParanoidErrorMessages()) {
                mesg.append("Cannot connect to MySQL server on ");
                mesg.append(this.host);
                mesg.append(":");
                mesg.append(this.port);
                mesg.append(".\n\n");
                mesg.append("Make sure that there is a MySQL server ");
                mesg.append("running on the machine/port you are trying ");
                mesg.append(
                    "to connect to and that the machine this software is "
                    + "running on ");
                mesg.append("is able to connect to this host/port "
                    + "(i.e. not firewalled). ");
                mesg.append(
                    "Also make sure that the server has not been started "
                    + "with the --skip-networking ");
                mesg.append("flag.\n\n");
            } else {
                mesg.append("Unable to connect to database.");
            }

            mesg.append("Underlying exception: \n\n");
            mesg.append(ex.getClass().getName());
            throw new java.sql.SQLException(mesg.toString(),
                SQLError.SQL_STATE_COMMUNICATION_LINK_FAILURE);
        }
    }

    /**
     * If a connection is in auto-commit mode, than all its SQL statements will
     * be executed and committed as individual transactions.  Otherwise, its
     * SQL statements are grouped into transactions that are terminated by
     * either commit() or rollback().  By default, new connections are in
     * auto- commit mode.  The commit occurs when the statement completes or
     * the next execute occurs, whichever comes first.  In the case of
     * statements returning a ResultSet, the statement completes when the last
     * row of the ResultSet has been retrieved or the ResultSet has been
     * closed.  In advanced cases, a single statement may return multiple
     * results as well as output parameter values.  Here the commit occurs
     * when all results and output param values have been retrieved.
     * 
     * <p>
     * <b>Note:</b> MySQL does not support transactions, so this method is a
     * no-op.
     * </p>
     *
     * @param autoCommit - true enables auto-commit; false disables it
     *
     * @exception java.sql.SQLException if a database access error occurs
     * @throws SQLException DOCUMENT ME!
     */
    public void setAutoCommit(boolean autoCommit) throws java.sql.SQLException {
        if (Driver.TRACE) {
            Object[] args = { new Boolean(autoCommit) };
            Debug.methodCall(this, "setAutoCommit", args);
        }

        checkClosed();

        if (this.transactionsSupported) {
            // this internal value must be set first as failover depends on it
            // being set to true to fail over (which is done by most
            // app servers and connection pools at the end of
            // a transaction), and the driver issues an implicit set
            // based on this value when it (re)-connects to a server
            // so the value holds across connections
            //
            this.autoCommit = autoCommit;

            //
            // This is to catch the 'edge' case of
            // autoCommit going from true -> false
            //
            if ((this.highAvailability || this.failedOver) && !this.autoCommit) {
                pingAndReconnect(true);
            }

            String sql = "SET autocommit=" + (autoCommit ? "1" : "0");
            execSQL(sql, -1, this.database);
        } else {
            if ((autoCommit == false) && (this.relaxAutoCommit == false)) {
                throw new SQLException("MySQL Versions Older than 3.23.15 "
                    + "do not support transactions",
                    SQLError.SQL_STATE_DRIVER_NOT_CAPABLE);
            } else {
                this.autoCommit = autoCommit;
            }
        }

        return;
    }

    /**
     * gets the current auto-commit state
     *
     * @return Current state of the auto-commit mode
     *
     * @exception java.sql.SQLException (why?)
     *
     * @see setAutoCommit
     */
    public boolean getAutoCommit() throws java.sql.SQLException {
        if (Driver.TRACE) {
            Object[] args = new Object[0];
            Debug.methodCall(this, "getAutoCommit", args);
            Debug.returnValue(this, "getAutoCommit",
                new Boolean(this.autoCommit));
        }

        return this.autoCommit;
    }

    /**
     * A sub-space of this Connection's database may be selected by setting a
     * catalog name.  If the driver does not support catalogs, it will
     * silently ignore this request
     * 
     * <p>
     * <b>Note:</b> MySQL's notion of catalogs are individual databases.
     * </p>
     *
     * @param catalog the database for this connection to use
     *
     * @throws java.sql.SQLException if a database access error occurs
     */
    public void setCatalog(String catalog) throws java.sql.SQLException {
        if (Driver.TRACE) {
            Object[] args = { catalog };
            Debug.methodCall(this, "setCatalog", args);
        }

        checkClosed();

        String quotedId = this.dbmd.getIdentifierQuoteString();

        if ((quotedId == null) || quotedId.equals(" ")) {
            quotedId = "";
        }

        StringBuffer query = new StringBuffer("USE ");
        query.append(quotedId);
        query.append(catalog);
        query.append(quotedId);

        execSQL(query.toString(), -1, catalog);
        this.database = catalog;
    }

    /**
     * Return the connections current catalog name, or null if no catalog name
     * is set, or we dont support catalogs.
     * 
     * <p>
     * <b>Note:</b> MySQL's notion of catalogs are individual databases.
     * </p>
     *
     * @return the current catalog name or null
     *
     * @exception java.sql.SQLException if a database access error occurs
     */
    public String getCatalog() throws java.sql.SQLException {
        if (Driver.TRACE) {
            Object[] args = new Object[0];
            Debug.methodCall(this, "getCatalog", args);
            Debug.returnValue(this, "getCatalog", this.database);
        }

        return this.database;
    }

    /**
     * Returns whether we clobber streaming results on new queries, or issue an
     * error?
     *
     * @return true if we should implicitly close streaming result sets upon
     *         receiving a new query
     */
    public boolean getClobberStreamingResults() {
        return this.clobberStreamingResults;
    }

    /**
     * DOCUMENT ME!
     *
     * @return DOCUMENT ME!
     */
    public boolean isClosed() {
        if (Driver.TRACE) {
            Object[] args = new Object[0];
            Debug.methodCall(this, "isClosed", args);
            Debug.returnValue(this, "isClosed", new Boolean(this.isClosed));
        }

        return this.isClosed;
    }

    /**
     * Returns the character encoding for this Connection
     *
     * @return the character encoding for this connection.
     */
    public String getEncoding() {
        return this.encoding;
    }

    /**
     * @see Connection#setHoldability(int)
     */
    public void setHoldability(int arg0) throws SQLException {
        // do nothing
    }

    /**
     * @see Connection#getHoldability()
     */
    public int getHoldability() throws SQLException {
        return ResultSet.CLOSE_CURSORS_AT_COMMIT;
    }

    /**
     * NOT JDBC-Compliant, but clients can use this method to determine how
     * long this connection has been idle. This time (reported in
     * milliseconds) is updated once a query has completed.
     *
     * @return number of ms that this connection has been idle, 0 if the driver
     *         is busy retrieving results.
     */
    public long getIdleFor() {
        if (this.lastQueryFinishedTime == 0) {
            return 0;
        } else {
            long now = System.currentTimeMillis();
            long idleTime = now - this.lastQueryFinishedTime;

            return idleTime;
        }
    }

    /**
     * Should we tell MySQL that we're an interactive client
     *
     * @return true if isInteractiveClient was set to true.
     */
    public boolean isInteractiveClient() {
        return isInteractiveClient;
    }

    /**
     * A connection's database is able to provide information describing its
     * tables, its supported SQL grammar, its stored procedures, the
     * capabilities of this connection, etc.  This information is made
     * available through a DatabaseMetaData object.
     *
     * @return a DatabaseMetaData object for this connection
     *
     * @exception java.sql.SQLException if a database access error occurs
     */
    public java.sql.DatabaseMetaData getMetaData() throws java.sql.SQLException {
        checkClosed();

        return new DatabaseMetaData(this, this.database);
    }

    /**
     * DOCUMENT ME!
     *
     * @return
     */
    public String getNegativeInfinityRep() {
        return negativeInfinityRep;
    }

    /**
     * DOCUMENT ME!
     *
     * @return
     */
    public boolean isNegativeInfinityRepIsClipped() {
        return negativeInfinityRepIsClipped;
    }

    /**
     * DOCUMENT ME!
     *
     * @return
     */
    public String getNotANumberRep() {
        return notANumberRep;
    }

    /**
     * DOCUMENT ME!
     *
     * @return
     */
    public boolean isNotANumberRepIsClipped() {
        return notANumberRepIsClipped;
    }

    /**
     * DOCUMENT ME!
     *
     * @return
     */
    public String getPositiveInfinityRep() {
        return positiveInfinityRep;
    }

    /**
     * DOCUMENT ME!
     *
     * @return
     */
    public boolean isPositiveInfinityRepIsClipped() {
        return positiveInfinityRepIsClipped;
    }

    /**
     * Should the driver do profiling?
     *
     * @param flag set to true to enable profiling.
     *
     * @throws SQLException if the connection is closed.
     */
    public void setProfileSql(boolean flag) throws SQLException {
        // For re-connection
        this.props.setProperty("profileSql", String.valueOf(flag));
        getIO().setProfileSql(flag);
    }

    /**
     * You can put a connection in read-only mode as a hint to enable database
     * optimizations <B>Note:</B> setReadOnly cannot be called while in the
     * middle of a transaction
     *
     * @param readOnly - true enables read-only mode; false disables it
     *
     * @exception java.sql.SQLException if a database access error occurs
     */
    public void setReadOnly(boolean readOnly) throws java.sql.SQLException {
        if (Driver.TRACE) {