匿名通过本文主要向大家介绍了mysql ，错误包等相关知识,希望本文的分享对您有所帮助
git
https://github.com/sea-boat/mysql-protocol
概况
mysql客户端与mysql服务端交互过程中，如果服务端遇到错误需要告知客户端则返回错误包。
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 |
错误包
Payload
| Type | Name | Description |
|---|---|---|
| int<1> | header | [ff] header of the ERR packet |
| int<2> | error_code | error-code |
| if capabilities & CLIENT_PROTOCOL_41 { | ||
| string[1] | sql_state_marker | marker of the SQL State |
| string[5] | sql_state | SQL State |
| } | ||
| string | error_message | human readable error message |
更多详情 ： http://dev.mysql.com/doc/internals/en/packet-ERR_Packet.html
错误包操作
错误包类
/**
*
* @author seaboat
* @date 2016-09-25
* @version 1.0
* <pre><b>email: </b>849586227@qq.com</pre>
* <pre><b>blog: </b>http:///;/pre>
* <p>mysql error packet.</p>
*/public class ErrorPacket extends MySQLPacket {
public static final byte header = (byte) 0xff;
private static final byte SQLSTATE_MARKER = (byte) '#';
private static final byte[] DEFAULT_SQLSTATE = "HY000".getBytes();
public int errno;
public byte mark = SQLSTATE_MARKER;
public byte[] sqlState = DEFAULT_SQLSTATE;
public byte[] message;
public void read(byte[] data) {
MySQLMessage mm = new MySQLMessage(data);
packetLength = mm.readUB3();
packetId = mm.read();
mm.read();
errno = mm.readUB2();
if (mm.hasRemaining() && (mm.read(mm.position()) == SQLSTATE_MARKER)) {
mm.read();
sqlState = mm.readBytes(5);
}
message = mm.readBytes();
}
public void write(ByteBuffer buffer) {
int size = calcPacketSize();
BufferUtil.writeUB3(buffer, size);
buffer.put(packetId);
buffer.put(header);
BufferUtil.writeUB2(buffer, errno);
buffer.put(mark);
buffer.put(sqlState);
buffer.put(message);
} @Override
public int calcPacketSize() {
int size = 9;// 1 + 2 + 1 + 5
if (message != null) {
size += message.length;
}
return size;
}
@Override
protected String getPacketInfo() {
return "MySQL Error Packet";
}
}十六进制转换工具
/**
*
* @author seaboat
* @date 2016-09-25
* @version 1.0
* <pre><b>email: </b>849586227@qq.com</pre>
* <pre><b>blog: </b>http:///;/pre>
* <p>hex transform util.</p>
*/public class HexUtil {
private final static byte[] hex = "0123456789ABCDEF".getBytes();
public static String Bytes2HexString(byte[] b) {
byte[] buff = new byte[2 * b.length];
for (int i = 0; i < b.length; i++) {
buff[2 * i] = hex[(b[i] >> 4) & 0x0f];
buff[2 * i + 1] = hex[b[i] & 0x0f];
} return new String(buff);
} public static String str2HexStr(String str) {
char[] chars = "0123456789ABCDEF".toCharArray();
StringBuilder sb = new StringBuilder("");
byte[] bs = str.getBytes();
int bit;
for (int i = 0; i < bs.length; i++) {
bit = (bs[i] & 0x0f0) >> 4;
sb.append(chars[bit]);
bit = bs[i] & 0x0f;
sb.append(chars[bit]);
} return sb.toString();
}
}错误包生成测试
/**
*
* @author seaboat
* @date 2016-09-25
* @version 1.0
* <pre><b>email: </b>849586227@qq.com</pre>
* <pre><b>blog: </b>http:///;/pre>
* <p>test auth packet.</p>
*/public class ErrorPacketTest {
@Test
public void produce() {
ErrorPacket err = new ErrorPacket();
err.packetId = 1;
err.errno = 32322;
err.message = "sorry".getBytes();
ByteBuffer buffer = ByteBuffer.allocate(256);
err.write(buffer);
buffer.flip(); byte[] bytes = new byte[buffer.remaining()];
buffer.get(bytes, 0, bytes.length);
String result = HexUtil.Bytes2HexString(bytes);
System.out.println(result);
assertTrue(Integer.valueOf(result.substring(0, 2), 16) == result
.length() / 2 - 4);
ErrorPacket err2 = new ErrorPacket();
err2.read(bytes);
assertTrue(err2.errno == 32322);
assertTrue(err2.message.length == "sorry".getBytes().length);
}
}以上就是详细介绍mysql 协议的错误包及解析的内容，更多相关内容请关注微课江湖（）！