连接mysql时一直出现以下的错误：

 

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.transaction.CannotCreateTransactionException: Could not open JDBC Connection for transaction; nested exception is java.sql.SQLException: Connections could not be acquired from the underlying database!	org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:982)	org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)	javax.servlet.http.HttpServlet.service(HttpServlet.java:634)	org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)	javax.servlet.http.HttpServlet.service(HttpServlet.java:741)	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) 然后就将“

Could not open JDBC Connection for transaction; nested exception is java.sql.SQLException: Connections could not be acquired from the underlying database!

” 当做问题的根源去搜索答案（当然，一搜发现这种错误还是挺多的）但是并不是我想要的答案 后来看到控制台的信息： java.sql.SQLException: Unknown system variable 'query_cache_size' 原来这才是问题的根源所在！！！ （这篇博客简直是救我于水深火热之中） 直接抄过来了 如果mysql驱动版本号不匹配的话会出现： java.sql.SQLException: Unknown system variable 'query_cache_size' java.sql.SQLException: Unknown system variable 'tx_read_only' java.sql.SQLException: Unknown system variable 'language' 解决办法，到 去找到你安装的mysql的版本对应的驱动版本号的配置 解决了这问题，又出现时区的问题，woc！！！ The server time zone value 'Öйú±ê׼ʱ¼ä' is unrecognized or represents more than one time zone. 请移步至