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Detailed introduction to the FieldList command package and analysis of the mysql protocol

黄舟
Release: 2017-03-07 13:45:41
Original
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git

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

Overview

When the mysql client uses the show column command, it corresponds to this FieldList command package.

mysql communication message structure

##string payloadMessage body, the length is the previously specified payload length
Type Name Description
int<3> payload length Stored according to the least significant byte first, 3-byte payload and 1-byte sequence number combination Into the message header
int<1> sequence number
FieldList command package

Payload

1              [04] COM_FIELD_LISTstring[NUL]    tablestring[EOF]    field wildcard
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More details: http://dev.mysql.com/doc/internals/en/com-field-list.html

FieldList command package operation

  1. FieldList command package class

  2. /**
     * 
     * <pre class="brush:php;toolbar:false"><b>mysql field list packet.</b>
    * @author *
    seaboat
    *
    <b>email: </b>849586227@qq.com
    *
    <b>blog: </b>http://www.php.cn/;/pre>
     * @version 1.0
     * @see http://www.php.cn/
     */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";
        }
    
    }
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