在JDBC使用的时候有时候会出现java.sql.SQLException: The server time zone value '???ú±ê×??±??' is unrecognized or represents........的错误，具体错误如下：
java.sql.SQLException: The server time zone value '�й���ʱ��' 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.
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:129) ~[mysql-connector-java-8.0.16.jar:8.0.16]
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97) ~[mysql-connector-java-8.0.16.jar:8.0.16]
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:89) ~[mysql-connector-java-8.0.16.jar:8.0.16]
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:63) ~[mysql-connector-java-8.0.16.jar:8.0.16]
出现这个的原因是因为 mysql返回的时间总是有问题，比实际时间要早8小时。
解决办法
public static final String URL="jdbc:mysql://localhost:3306/jdbc01?useUnicode=true&characterEncoding=utf8&serverTimezone=GMT%2B8&useSSL=false";//链接的mysql
在jdbc连接的url后面加上serverTimezone=GMT即可解决问题，如果需要使用gmt+8时区，需要写成GMT%2B8
问题就会解决；
