2018-09-25 16:16:16.264  INFO 15528 --- [       main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Starting...
Tue Sep 25 16:16:16 CST 2018 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.
2018-09-25 16:16:17.403 ERROR 15528 --- [       main] com.zaxxer.hikari.pool.HikariPool        : HikariPool-1 - Exception during pool initialization.

java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: NO)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:965) ~[mysql-connector-java-5.1.46.jar:5.1.46]
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3976) ~[mysql-connector-java-5.1.46.jar:5.1.46]
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3912) ~[mysql-connector-java-5.1.46.jar:5.1.46]
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:871) ~[mysql-connector-java-5.1.46.jar:5.1.46]
 at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1714) ~[mysql-connector-java-5.1.46.jar:5.1.46]
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1224) ~[mysql-connector-java-5.1.46.jar:5.1.46]

在Mysql5.5以上的版本中，建立連線時會警告：

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.

   不建議在沒有伺服器身份驗證的情況下建立SSL連線。根據MySQL 5.5.45+、5.6.26+和5.76+的要求，如果不設定顯式選項，則必須在預設情況下建立SSL連線。為了遵守不使用SSL的現有應用程式，verifyserver證書屬性被設定為“false”。您需要通過設定useSSL=false來顯式禁用SSL，或者設定useSSL=true，併為伺服器證書驗證提供信任儲存。

  這警告實際上不止出現在啟動專案時，在啟動MySql服務時，日誌中就會給出警告，告知不建議使用沒有帶伺服器身份驗證的SSL連線。

解決辦法在警告中已經說明：

1.在資料庫連線的url中新增useSSL=false;

2.url中新增useSSL=true，並且提供伺服器的驗證證書。

例如：  jdbc:mysql://127.0.0.1:3306/sbcharon?useSSL=true