背景知识:
我有一个运行在Tomcat 7上的Java 1.6 web应用程序。数据库为MySQL 5.5。之前，我使用Mysql JDBC驱动程序5.1.23连接到DB。一切工作。我最近升级到Mysql JDBC驱动程序5.1.33。升级后，Tomcat在启动应用程序时会抛出这个错误。
WARNING: Unexpected exception resolving reference
java.sql.SQLException: The server timezone value 'UTC' is unrecognized or represents
more than one timezone. You must configure either the server or JDBC driver (via
the serverTimezone configuration property) to use a more specifc timezone value if
you want to utilize timezone support.
为什么会这样?
当前回答
显然，要使MySQL JDBC驱动程序5.1.33版本与UTC时区兼容，必须在连接字符串中显式指定serverTimezone。
jdbc:mysql://localhost/db?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC
其他回答
在mysql工作台中运行以下sql语句:
设置@@global。Time_zone = '+00:00'; 设置@@session。Time_zone = '+00:00';
使用以下SQL语句检查是否设置了值:
选择@@global。time_zone @@session.time_zone;
当我尝试在windows上使用spring boot项目时，我遇到了同样的问题。
数据源url应该是:
spring.datasource.url = jdbc: mysql: / / localhost /数据库?useUnicode = true&useJDBCCompliantTimezoneShift = true&useLegacyDatetimeCode = false&serverTimezone = UTC
显然，要使MySQL JDBC驱动程序5.1.33版本与UTC时区兼容，必须在连接字符串中显式指定serverTimezone。
jdbc:mysql://localhost/db?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC
我解决了把下面的连接字符串在URL
jdbc:mysql://localhost:3306/db?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC
在阅读了几篇关于这个主题的文章后，测试了不同的配置，并根据这个mysql bug线程的一些见解，我明白了:
the server time zone is important in particular to convert dates stored in the database to the time zone of the application server. there are other implications but this is the most noticeable one GMT x UTC time zone systems. GMT was conceived in the late 19th century and can be shifted between standard time and summer time. this property could lead to a situation where the database server shifts to summer time and the application doesn't notice it (perhaps there are other complications but I didn't research further). UTC does not vary over time (it is always within about 1 second of mean solar time at 0° longitude). serverTimeZone definition was introduced in mysql jdbc connectors versions 5.1 ahead. until version 8 it could be ignored with useLegacyDatetimeCode=true , which in conjunction with useJDBCCompliantTimezoneShift=true would make the application get the database time zone on every connection. In this mode GMT time zones such as 'British Summer Time' would be converted to the internal java/JDBC format. New time zones could be defined in a .properties file such as this one Starting with jdbc driver version 8, automatic time matching (useJDBCCompliantTimezoneShift) and legacy time format (useLegacyDatetimeCode) were removed (see mysql jdbc connector changelog). therefore setting these 2 parameters has no effect as they are completely ignored (new default is useLegacyDateTimeCode=false) In this manner setting serverTimezone became mandatory if any of the time zones (application/database servers) are not in the format 'UTC+xx' or 'GMT+xx' There is no impact of setting server time as UTC (for instance with jdbc:mysql://localhost:3306/myschema?serverTimezone=UTC, even if your application / database servers are not in this timezone. The important is for the application connection string + database to be synchronized with the same time zone. In different words, simply setting serverTimezone=UTC with a different time zone on the database server will shift any dates extracted from the database The MySQL default time zone can be set to UTC+0 with the my.ini or my.cnf files (windows / linux respectively) by adding the line default-time-zone='+00:00' (details in this StackOverflow post) Databases configured on AWS (amazon web services) are automatically assigned UTC+0 default time (see AWS help page here)
