Java连接MySQL报出警告 WARN: Establishing SSL connection without server's identity verification is not recommended.

很多人使用JDBC连接MySQL时报出警告：

WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.

警告：不建议在没有服务器身份验证的情况下建立SSL连接。根据MySQL 5.5.45+、5.6.26+和5.76+的要求，如果不进行显示选项设置，则必须在默认情况下建立SSL连接。为了符合现有的不使用SSL的应用程序，认证服务器证书属性被设置为“false”。您需要通过设置useSSL=false来显式禁用SSL，或者设置useSSL=true，并为服务器证书验证提供信任存储。

简单来说就是MySQL高版本中默认进行SSL连接，我们需要显示设置禁用SSL连接：

url = jdbc:mysql://127.0.0.1:3306/database?useUnicode=true&characterEnocding=utf-8&useSSL=false