各位 Java 大佬好，先给大佬倒茶。关于 jdbc 与 mysql 交互问题

是这样我想知道 jdbc 与 mysql 交互，源码上网边看边查到 mysqlIO.class ，问题是我如果 jdbc 里面数据库名或者密码错了（虽然我知道错的），底层是怎么判断的 ，目的是要这套判断，和判断结果，套用在自己的数据上面，相当于借用他们的标准套在我们的数据库上面，以后也好形成统一。 还望各位大佬们不吝赐教，指条明路。我是菜鸡，只管喷。 祝大佬 情绪稳定，睡眠良好，头发浓密

目前代码看到这里 mysqlIO.class

void secureAuth411(Buffer packet, int packLength, String user, String password, String database, boolean writeClientParams) throws SQLException { String enc = this.getEncodingForHandshake(); if (packet == null) { packet = new Buffer(packLength); }

if (writeClientParams) {
    if (this.use41Extensions) {
        if (this.versionMeetsMinimum(4, 1, 1)) {
            packet.writeLong(this.clientParam);
            packet.writeLong((long)this.maxThreeBytes);
            this.appendCharsetByteForHandshake(packet, enc);
            packet.writeBytesNoNull(new byte[23]);
        } else {
            packet.writeLong(this.clientParam);
            packet.writeLong((long)this.maxThreeBytes);
        }
    } else {
        packet.writeInt((int)this.clientParam);
        packet.writeLongInt(this.maxThreeBytes);
    }
}
// 设置用户名
packet.writeString(user, enc, this.connection);
if (password.length() != 0) {
    packet.writeByte((byte)20);

    
    try {
        // 设置密码 
        packet.writeBytesNoNull(Security.scramble411(password, this.seed, this.connection.getPasswordCharacterEncoding()));
    } catch (NoSuchAlgorithmException var11) {
        throw SQLError.createSQLException(Messages.getString("MysqlIO.95") + Messages.getString("MysqlIO.96"), "S1000", this.getExceptionInterceptor());
    } catch (UnsupportedEncodingException var12) {
        throw SQLError.createSQLException(Messages.getString("MysqlIO.95") + Messages.getString("MysqlIO.96"), "S1000", this.getExceptionInterceptor());
    }
} else {
    packet.writeByte((byte)0);
}

// 设置数据库名
if (this.useConnectWithDb) {
    packet.writeString(database, enc, this.connection);
} else {
    packet.writeByte((byte)0);
}

if ((this.serverCapabilities & 1048576) != 0) {
    this.sendConnectionAttributes(packet, enc, this.connection);
}
// 向 Mysql 服务器发送登录信息包(用户名、密码、此 Socket 连接默认选择的数据库)
this.send(packet, packet.getPosition());
byte var10002 = this.packetSequence;
this.packetSequence = (byte)(var10002 + 1);
byte savePacketSequence = var10002;

// 读取 Mysql 服务器登录检验后发送的状态信息，如果成功就返回，如果登录失败则抛出异常 
Buffer reply = this.checkErrorPacket();
if (reply.isLastDataPacket()) {
    ++savePacketSequence;
    this.packetSequence = savePacketSequence;
    packet.clear();
    String seed323 = this.seed.substring(0, 8);
    packet.writeString(Util.newCrypt(password, seed323));
    this.send(packet, packet.getPosition());
    this.checkErrorPacket();
}

}