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mysql 协议的ColumnDefinition包及解析

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[数据库(mysql) 所属分类 数据库(mysql) | 发布者 店小二05 | 时间 2017 | 作者 红领巾 ] 0人收藏点击收藏
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<3> 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<1> 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 set 4 column length 1 type 2 flags 1 decimals 2 filler [00] [00] if command was COM_FIELD_LIST { lenenc_int length of default-values string[$len] default values }

更多详情 : http://dev.mysql.com/doc/internals/en/com-query-response.html#column-definition

ColumnCount包类 /** * * <pre><b>column definition command packet.</b></pre> * @author * <pre>seaboat</pre> * <pre><b>email: </b>[email protected]</pre> * <pre><b>blog: </b>http://blog.csdn.net/wangyangzhizhou</pre> * @version 1.0 * @see http://dev.mysql.com/doc/internals/en/com-query-response.html#column-definition */ 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"; } }

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