requeststream.java

jtds的源码 是你学习java的好东西

        write((byte) l);
        write((byte) (l >> 8));
        write((byte) (l >> 16));
        write((byte) (l >> 24));
    }

    /**
     * Write a String object to the output stream.
     * If the TDS version is >= 7.0 write a UNICODE string otherwise
     * wrote a translated byte stream.
     *
     * @param s The String to write.
     * @throws IOException
     */
    void write(String s) throws IOException {
        if (socket.getTdsVersion() >= Driver.TDS70) {
            int len = s.length();

            for (int i = 0; i < len; ++i) {
                int c = s.charAt(i);

                if (bufferPtr == buffer.length) {
                    putPacket(0);
                }

                buffer[bufferPtr++] = (byte) c;

                if (bufferPtr == buffer.length) {
                    putPacket(0);
                }

                buffer[bufferPtr++] = (byte) (c >> 8);
            }
        } else {
            writeAscii(s);
        }
    }

    /**
     * Write a char array object to the output stream.
     *
     * @param s The char[] to write.
     * @throws IOException
     */
    void write(char s[], int off, int len) throws IOException {
        int i = off;
        int limit = (off + len) > s.length ? s.length : off + len;

        for ( ; i < limit; i++) {
            char c = s[i];

            if (bufferPtr == buffer.length) {
                putPacket(0);
            }

            buffer[bufferPtr++] = (byte) c;

            if (bufferPtr == buffer.length) {
                putPacket(0);
            }

            buffer[bufferPtr++] = (byte) (c >> 8);
        }
    }

    /**
     * Write a String to the output stream as translated bytes.
     *
     * @param s The String to write.
     * @throws IOException
     */
    void writeAscii(String s) throws IOException {
        String charsetName = socket.getCharset();

        if (charsetName != null) {
            try {
                write(s.getBytes(charsetName));
            } catch (UnsupportedEncodingException e) {
                write(s.getBytes());
            }
        } else {
            write(s.getBytes());
        }
    }

    /**
     * Copy the contents of an InputStream to the server.
     *
     * @param in The InputStream to read.
     * @param length The length of the stream.
     * @throws IOException
     */
    void writeStreamBytes(InputStream in, int length) throws IOException {
        byte buffer[] = new byte[1024];

        while (length > 0) {
            int res = in.read(buffer);

            if (res < 0) {
                throw new java.io.IOException(
                        "Data in stream less than specified by length");
            }

            write(buffer, 0, res);
            length -= res;
        }

        // XXX Not sure that this is actually an error
        if (length < 0 || in.read() >= 0) {
            throw new java.io.IOException(
                    "More data in stream than specified by length");
        }
    }

    /**
     * Copy the contents of a Reader stream to the server.
     *
     * @param in The Reader object with the data.
     * @param length The length of the data in characters.
     * @throws IOException
     */
    void writeReaderChars(Reader in, int length) throws IOException {
        char cbuffer[] = new char[512];
        byte bbuffer[] = new byte[1024];

        while (length > 0) {
            int res = in.read(cbuffer);

            if (res < 0) {
                throw new java.io.IOException(
                        "Data in stream less than specified by length");
            }

            for (int i = 0, j = -1; i < res; i++) {
                bbuffer[++j] = (byte) cbuffer[i];
                bbuffer[++j] = (byte) (cbuffer[i] >> 8);
            }

            write(bbuffer, 0, res * 2);
            length -= res;
        }

        // XXX Not sure that this is actually an error
        if (length < 0 || in.read() >= 0) {
            throw new java.io.IOException(
                    "More data in stream than specified by length");
        }
    }

    /**
     * Copy the contents of a Reader stream to the server as bytes.
     * <p>
     * NB. Only reliable where the charset is single byte.
     *
     * @param in The Reader object with the data.
     * @param length The length of the data in bytes.
     * @throws IOException
     */
    void writeReaderBytes(Reader in, int length) throws IOException {
        char buffer[] = new char[1024];

        for (int i = 0; i < length;) {
            int result = in.read(buffer);

            if (result == -1) {
                throw new java.io.IOException(
                        "Data in stream less than specified by length");
            } else if (i + result > length) {
                throw new java.io.IOException(
                        "More data in stream than specified by length");
            }

            write(Support.encodeString(socket.getCharset(), new String(buffer, 0, result)));
            i += result;
        }
    }

    /**
     * Write a BigDecimal value to the output stream.
     *
     * @param value The BigDecimal value to write.
     * @throws IOException
     */
    void write(BigDecimal value) throws IOException {

        if (value == null) {
            write((byte) 0);
        } else {
            byte signum = (byte) (value.signum() < 0 ? 0 : 1);
            BigInteger bi = value.unscaledValue();
            byte mantisse[] = bi.abs().toByteArray();
            byte len = (byte) (mantisse.length + 1);

            if (len > getMaxDecimalBytes()) {
                // Should never happen now as value is normalized elsewhere
                throw new IOException("BigDecimal to big to send");
            }

            if (socket.serverType == Driver.SYBASE) {
                write((byte) len);
                // Sybase TDS5 stores MSB first opposite sign!
                // length, prec, scale already sent in parameter descriptor.
                write((byte) ((signum == 0) ? 1 : 0));

                for (int i = 0; i < mantisse.length; i++) {
                    write((byte) mantisse[i]);
                }
            } else {
                write((byte) len);
                write((byte) signum);

                for (int i = mantisse.length - 1; i >= 0; i--) {
                    write((byte) mantisse[i]);
                }
            }
        }
    }

    /**
     * Flush the packet to the output stream setting the last packet flag.
     *
     * @throws IOException
     */
    void flush() throws IOException {
        putPacket(1);
    }

    /**
     * Close the output stream.
     */
    void close() {
        isClosed = true;
    }

    /**
     * Retrieve the TDS version number.
     *
     * @return The TDS version as an <code>int</code>.
     */
    int getTdsVersion() {
        return socket.getTdsVersion();
    }

    /**
     * Retrieve the Server type.
     *
     * @return The Server type as an <code>int</code>.
     */
    int getServerType() {
        return socket.serverType;
    }

    /**
     * Write the TDS packet to the network.
     *
     * @param last Set to 1 if this is the last packet else 0.
     * @throws IOException
     */
    private void putPacket(int last) throws IOException {
        if (isClosed) {
            throw new IOException("RequestStream is closed");
        }

        buffer[0] = pktType;
        buffer[1] = (byte) last; // last segment indicator
        buffer[2] = (byte) (bufferPtr >> 8);
        buffer[3] = (byte) bufferPtr;
        buffer[4] = 0;
        buffer[5] = 0;
        buffer[6] = (byte) ((socket.getTdsVersion() >= Driver.TDS70) ? 1 : 0);
        buffer[7] = 0;

        if (Logger.isActive()) {
            Logger.logPacket(streamId, false, buffer);
        }

        buffer = socket.sendNetPacket(streamId, buffer);
        bufferPtr = TdsCore.PKT_HDR_LEN;
    }
}