1--Unknown initial character set index '255' received from server. Initial client character set can be

mysql的連線錯誤，在網上查詢到是編碼不匹配的原因，

但是確認了一遍沒找到編碼不是utf8的情況，

在連線的URL後加上

?useUnicode=true&characterEncoding=utf8

2--java.sql.SQLException: The server time zone value '???ú±ê×??±??' is unrecognized or represents more than one time zone.

在連線的URL後加上 

?serverTimezone=GMT%2B8&

使用的資料庫是MySQL，驅動是8.0.11，這是由於資料庫和系統時區差異所造成的，在jdbc連線的url後面加上serverTimezone=GMT即可解決問題，如果需要使用gmt+8時區，需要寫成GMT%2B8，否則會被解析為空。再一個解決辦法就是使用低版本的MySQL jdbc驅動，5.1.28不會存在時區的問題。

3--Fri May 18 15:00:19 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.

 

在連線的URL後加上

useSSL=false

4--Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.  

不能這樣 driverClass="com.mysql.jdbc.Driver" 

應該修改成 driverClass="com.mysql.cj.jdbc.Driver"