mysql 協(xié)議的ColumnDefinition包及解析代碼詳情

lenenc_str?????catalog  lenenc_str?????schema  lenenc_str?????table  lenenc_str?????org_table  lenenc_str?????name  lenenc_str?????org_name  lenenc_int?????length?of?fixed-length?fields?[0c]2??????????????  character?set4??????????????  column?length1??????????????  type2??????????????  flags1??????????????  decimals2??????????????  filler?[00]?[00]??if?command?was?COM_FIELD_LIST?{  lenenc_int?????  length?of?default-valuesstring[$len]???  default?values  ??}

/**  ?*?  ?*?<pre class="brush:php;toolbar:false"><b>column definition command packet.</b>

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<b>blog: </b>http://www.php.cn/;/pre>   * @version 1.0   * @see http://www.php.cn/   */public class ColumnDefinitionPacket extends MySQLPacket {      private static final byte[] DEFAULT_CATALOG = "def".getBytes();          private static final byte NEXT_LENGTH = 0x0c;          private static final byte[] FILLER = { 00, 00 };          public byte[] catalog = DEFAULT_CATALOG;// always "def"      public byte[] schema;          public byte[] table;          public byte[] orgTable;          public byte[] name;          public byte[] orgName;          public byte nextLength = NEXT_LENGTH;// always 0x0c      public int charsetSet;          public long length;          public int type;          public int flags;          public byte decimals;          public byte[] filler = FILLER;          public byte[] defaultValues;          public void read(byte[] data) {          MySQLMessage mm = new MySQLMessage(data);                  this.packetLength = mm.readUB3();                  this.packetId = mm.read();                  this.catalog = mm.readBytesWithLength();                  this.schema = mm.readBytesWithLength();                  this.table = mm.readBytesWithLength();                  this.orgTable = mm.readBytesWithLength();                  this.name = mm.readBytesWithLength();                  this.orgName = mm.readBytesWithLength();                  this.nextLength = mm.read();                  this.charsetSet = mm.readUB2();                  this.length = mm.readUB4();                  this.type = mm.read() & 0xff;                  this.flags = mm.readUB2();                  this.decimals = mm.read();                  this.filler = mm.readBytes(2);                  if (mm.hasRemaining()) {                      this.defaultValues = mm.readBytesWithLength();          }      }    @Override      public void write(ByteBuffer buffer) {              int size = calcPacketSize();          BufferUtil.writeUB3(buffer, size);          buffer.put(packetId);          BufferUtil.writeWithLength(buffer, catalog, (byte) 0);          BufferUtil.writeWithLength(buffer, schema, (byte) 0);          BufferUtil.writeWithLength(buffer, table, (byte) 0);          BufferUtil.writeWithLength(buffer, orgTable, (byte) 0);          BufferUtil.writeWithLength(buffer, name, (byte) 0);          BufferUtil.writeWithLength(buffer, orgName, (byte) 0);          buffer.put(NEXT_LENGTH);          BufferUtil.writeUB2(buffer, charsetSet);          BufferUtil.writeUB4(buffer, length);          buffer.put((byte) (type & 0xff));          BufferUtil.writeUB2(buffer, flags);          buffer.put(decimals);          buffer.put(FILLER);                  if (defaultValues != null) {                      //only use for show columns              BufferUtil.writeWithLength(buffer, defaultValues);          }      }    @Override      public int calcPacketSize() {              int size = (catalog == null ? 1 : BufferUtil.getLength(catalog));          size += (schema == null ? 1 : BufferUtil.getLength(schema));          size += (table == null ? 1 : BufferUtil.getLength(table));          size += (orgTable == null ? 1 : BufferUtil.getLength(orgTable));          size += (name == null ? 1 : BufferUtil.getLength(name));          size += (orgName == null ? 1 : BufferUtil.getLength(orgName));          size += 13;        if (defaultValues != null) {              size += BufferUtil.getLength(defaultValues);          }                  return size;      }          @Override      protected String getPacketInfo() {              return "MySQL Column Definition Packet";      }    }