解决方法
Etc / GMT与UTC或GMT不是完全相同的.它们在偏移量为0时表示相同的时刻.在所有其他情况下,它们是完全不同的.
直接从链接引用的例子就是：
We use POSIX-style signs in the Zone names and the output abbreviations,even though this is the opposite of what many people expect. POSIX has positive signs west of Greenwich,but many people expect positive signs east of Greenwich. For example,TZ=’Etc/GMT+4′ uses the abbreviation “GMT+4” and corresponds to 4 hours behind UTC (i.e. west of Greenwich) even though many people would expect it to mean 4 hours ahead of UTC (i.e. east of Greenwich).
