用于远程调用Mysql

Add remote user to Mysql from for exemple IP=remoteIP : mysql -u xxxx -p //local coonection to mysql mysql> GRANT ALL PRIVILEGES ON *.* TO 'theNewUser'@'remoteIP' IDENTIFIED BY 'passWord'; //Query OK, 0 rows affected (xx sec) mysql> FLUSH PRIVILEGES; //Query OK, 0 rows affected Allow remote access to Mysql (by default all externall call is not allowed): Edit /etc/mysql/mysql.conf.d/mysqld.cnf or /etc/mysql/my.cnf Change line: bind-address = 127.0.0.1 to bind-address = 0.0.0.0 Restart Mysql: /etc/init.d/mysql restart For The latest version of JDBC Driver, the JDBC : jdbc.url='jdbc:mysql://remoteIP:3306/yourDbInstance?autoReconnect=true&useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC' jdbc.user='theNewUser'

尝试将localhost更改为127.0.0.1。

本地主机将被解析为::1。MySQL默认不支持IPv6连接。

下面是telnet localhost 3306的输出:

$ telnet localhost 3306
Trying ::1...

MySQL服务器没有响应。

当然，请确保您的MySQL服务器正在运行。

如果Java试图通过SSL连接MySQL，但出现了错误，也可能发生此错误。(在我的例子中，我将Payara Server 5.193.1连接池配置为MySQL。)

有人建议设置useSSL=false。但是，由于Connector/J版本8.0.13，该设置已弃用。下面是MySQL连接器/J 8.0配置属性的摘录:

sslMode By default, network connections are SSL encrypted; this property permits secure connections to be turned off, or a different levels of security to be chosen. The following values are allowed: DISABLED - Establish unencrypted connections; PREFERRED - (default) Establish encrypted connections if the server enabled them, otherwise fall back to unencrypted connections; REQUIRED - Establish secure connections if the server enabled them, fail otherwise; VERIFY_CA - Like REQUIRED but additionally verify the server TLS certificate against the configured Certificate Authority (CA) certificates; VERIFY_IDENTITY - Like VERIFY_CA, but additionally verify that the server certificate matches the host to which the connection is attempted. This property replaced the deprecated legacy properties useSSL, requireSSL, and verifyServerCertificate, which are still accepted but translated into a value for sslMode if sslMode is not explicitly set: useSSL=false is translated to sslMode=DISABLED; {"useSSL=true", "requireSSL=false", "verifyServerCertificate=false"} is translated to sslMode=PREFERRED; {"useSSL=true", "requireSSL=true", "verifyServerCertificate=false"} is translated to sslMode=REQUIRED; {"useSSL=true" AND "verifyServerCertificate=true"} is translated to sslMode=VERIFY_CA. There is no equivalent legacy settings for sslMode=VERIFY_IDENTITY. Note that, for ALL server versions, the default setting of sslMode is PREFERRED, and it is equivalent to the legacy settings of useSSL=true, requireSSL=false, and verifyServerCertificate=false, which are different from their default settings for Connector/J 8.0.12 and earlier in some situations. Applications that continue to use the legacy properties and rely on their old default settings should be reviewed. The legacy properties are ignored if sslMode is set explicitly. If none of sslMode or useSSL is set explicitly, the default setting of sslMode=PREFERRED applies. Default: PREFERRED Since version: 8.0.13

因此，在我的例子中，设置sslMode=DISABLED就是解决这个问题所需要的全部内容。 这是在一台测试机器上。但是对于生产环境，安全解决方案应该正确配置Java客户机和MySQL服务器以使用SSL。

注意，通过禁用SSL，您可能还必须设置allowPublicKeyRetrieval=true。(同样，从安全角度来看，这不是一个明智的决定)。进一步的信息提供在MySQL ConnectionString选项:

AllowPublicKeyRetrieval If the user account uses sha256_password authentication, the password must be protected during transmission; TLS is the preferred mechanism for this, but if it is not available then RSA public key encryption will be used. To specify the server’s RSA public key, use the ServerRSAPublicKeyFile connection string setting, or set AllowPublicKeyRetrieval=True to allow the client to automatically request the public key from the server. Note that AllowPublicKeyRetrieval=True could allow a malicious proxy to perform a MITM attack to get the plaintext password, so it is False by default and must be explicitly enabled.

用于远程调用Mysql

Add remote user to Mysql from for exemple IP=remoteIP : mysql -u xxxx -p //local coonection to mysql mysql> GRANT ALL PRIVILEGES ON *.* TO 'theNewUser'@'remoteIP' IDENTIFIED BY 'passWord'; //Query OK, 0 rows affected (xx sec) mysql> FLUSH PRIVILEGES; //Query OK, 0 rows affected Allow remote access to Mysql (by default all externall call is not allowed): Edit /etc/mysql/mysql.conf.d/mysqld.cnf or /etc/mysql/my.cnf Change line: bind-address = 127.0.0.1 to bind-address = 0.0.0.0 Restart Mysql: /etc/init.d/mysql restart For The latest version of JDBC Driver, the JDBC : jdbc.url='jdbc:mysql://remoteIP:3306/yourDbInstance?autoReconnect=true&useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC' jdbc.user='theNewUser'

我用一种简单的方法解决了这个问题，这对我很有用。我遇到了一些问题"com.mysql.jdbc.exceptions.jdbc4。CommunicationsException:通信链路故障”。在我的数据库里。属性文件我有这个:url:jdbc:mysql://localhost:90/myDB 只删除了端口url，导致这种方式url:jdbc:mysql://localhost/myDB，这对我来说是有效的。

这com.mysql.jdbc.exceptions.jdbc4。如果数据库连接长时间空闲，将发生CommunicationsException异常。

这个空闲连接在connection. isclosed()上返回true;但如果我们尝试执行语句，它就会触发这个异常，所以我建议使用数据库池。