git
https://github.com/sea-boat/mysql-protocol
概况
ColumnDefinition包属于服务端返回ResultSet时的其中一部分包，用于描述结果集的字段信息。
mysql通信报文结构
| 类型 | 名字 | 描述 |
|---|---|---|
| int | payload长度 | 按照the least significant byte first存储，3个字节的payload和1个字节的序列号组合成报文头 |
| int | 序列号 | |
| string | payload | 报文体，长度即为前面指定的payload长度 |
ColumnDefinition包
Payload
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
}更多详情 ： http://dev.mysql.com/doc/internals/en/com-query-response.html#column-definition
ColumnCount包类
/** * *column definition command packet.* @author *seaboat*email: 849586227@qq.com*blog: 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"; } }以上就是mysql 协议的ColumnDefinition包及解析代码详情的内容，更多相关内容请关注PHP中文网（www.php.cn）！
