详细介绍mysql协议的FieldList命令包及解析

来源：递易科技网

git

https://github.com/sea-boat/mysql-protocol

概况

当mysql客户端使用show column命令时即对应这个FieldList命令包。

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

FieldList命令包

Payload

1 [04] COM_FIELD_LISTstring[NUL] tablestring[EOF] field wildcard

更多详情： http://dev.mysql.com/doc/internals/en/com-field-list.html

FieldList命令包操作

FieldList命令包类

/**
 * 
 * <pre><b>mysql field list packet.</b></pre>
 * @author 
 * <pre>seaboat</pre>
 * <pre><b>email: </b>849586227@qq.com</pre>
 * <pre><b>blog: </b>http://www.gxlcms.com/;/pre>
 * @version 1.0
 * @see http://www.gxlcms.com/
 */public class FieldListPacket extends MySQLPacket {
 public byte flag; public byte[] table; public byte[] fieldWildcard; @Override
 public void read(byte[] data) {
 MySQLMessage mm = new MySQLMessage(data);
 packetLength = mm.readUB3();
 packetId = mm.read();
 flag = mm.read();
 table = mm.readBytesWithNull();
 fieldWildcard = mm.readBytes();
 } @Override
 public void write(ByteBuffer buffer) {
 BufferUtil.writeUB3(buffer, calcPacketSize());
 buffer.put(packetId);
 buffer.put(COM_FIELD_LIST);
 BufferUtil.writeWithNull(buffer, table);
 buffer.put(fieldWildcard);
 } @Override
 public int calcPacketSize() { int i = 1;
 i += table.length + 1;
 i += fieldWildcard.length; return i;
 } @Override
 protected String getPacketInfo() { return "MySQL Field List Packet";
 }

}