mysql8.0後產生的錯誤

mysql連接錯誤，有時候存在時區問題，
錯誤提示：
The server time zone value ‘¥x¥_¼Ð·Ç®É¶¡’ is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc time zone value if you want to utilize time zone support.

解決辦法：
在jdbc連接的url後面加上serverTimezone=Asia/Shanghai,原因是因爲 mysql 屬於 oralce 公司,oracle 公司位於美國所以時區跟我們不同，我們需要更改爲我們國內的時期

jdbc.url=jdbc:mysql://localhost:3306/xxx?useUnicode=true&characterEncoding=utf8&serverTimezone=Asia/Shanghai

Thu Aug 01 04:57:12 UTC 2019 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.

jdbc.url=jdbc:mysql://localhost:3306/xxx?useUnicode=true&characterEncoding=utf8&serverTimezone=Asia/Shanghai&useSSL=false

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java.sql.SQLException: Unknown system variable ‘query_cache_size’

解決辦法：

如 mybatis使用 mysql-5.1.14的驅動程序，而mybatis配置的數據源連接的是 mysql-8.0.11 ，修改 pom文件即可，如下：

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.11</version>
</dependency>

根據官方的說法是 :

The query cache is deprecated as of MySQL 5.7.20, and is removed in MySQL 8.0. Deprecation includes query_cache_size.

意思是query cache在MySQL5.7.20就已經過時了，而在MySQL8.0之後就已經被移除了。