最近很多次遇到
The server time zone value 'Öйú±ê׼ʱ¼ä' is unrecognized or represents more than one time zone
这个问题，
报错为：
org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.PersistenceException: ### Error querying database. Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: Connections could not be acquired from the underlying database!### The error may exist in com/wj/mapper/UserLoginMapper.xml### The error may involve com.wj.mapper.UserLoginMapper.selectByName### The error occurred while executing a query### Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; 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.doPost(FrameworkServlet.java:872)
javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
root cause
java.sql.SQLException: The server time zone value 'Öйú±ê׼ʱ¼ä'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.
com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:127)
com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:95)
com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:87)
com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:61)
com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:71)
com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:76)
com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:862)
com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:444)
com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:230)
com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:226)
com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:175)
com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:220)
com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:206)
com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:203)
com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138)
com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125)
com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44)
com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870)
com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696)
网上说法也很多，经过测试，有效的一个办法如下：
image.png
即可解决这个错误！
情况二
mysql serverTimezone useSSL 時差
剛開始遇到這個問題很驚訝，爲何我往數據庫添加的時間明明是當前時間（例：2019-3-03-29 09：00：00），然而數據庫中顯示的時間卻少了8個小時（例：2019-3-03-29 01：00：00）。很明顯，8個小時的時差，而且北京時區爲東八區，這應該就是時區設置問題了。
查看了一下項目中的數據庫連接設置，如下：
hibernate.dialect=org.hibernate.dialect.MySQL8Dialect
jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql:/127.0.0.1:8080/test?useSSL=false&serverTimezone=UTC
jdbc.username=root
jdbc.password=root
發現其中serverTimezone設置的值爲UTC，UTC代表的是全球標準時間 ，而我們所在的時區是東八區，領先UTC八個小時，這就是導致問題所在了。
解決方法：將serverTimezone設置爲北京時間或者上海時間來解決。
//北京時間東八區
serverTimezone=GMT%2B8
//上海時間
serverTimezone=Asia/Shanghai
