用aeson解析utctime

本文介绍了用aeson解析utctime的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我无法通过eson解析UTCTime值.我试图对其中一个进行编码并将其反馈，但是那没有用:

I can't get aeson to parse an UTCTime value. I tried to encode one and feed it back, but that didn't work:

Prelude Data.Aeson Data.Time.Clock> getCurrentTime >>= (print . encode)
"\"2013-10-17T09:42:49.007Z\""
Prelude Data.Aeson Data.Time.Clock> decode "2013-10-17T09:42:49.007Z" :: Maybe UTCTime
Nothing
Prelude Data.Aeson Data.Time.Clock> decode "\"2013-10-17T09:42:49.007Z\"" :: Maybe UTCTime
Nothing

UTCTime类型的FromJSON实例如下():

The FromJSON instance of the UTCTime type is the following (ref):

instance FromJSON UTCTime where
    parseJSON = withText "UTCTime" $ \t ->
        case parseTime defaultTimeLocale "%FT%T%QZ" (unpack t) of
          Just d -> pure d
          _      -> fail "could not parse ISO-8601 date"

在此处找到格式说明之后，没事.我想念什么?

following the format description found here, everything should be ok. What am I missing?

推荐答案

Prelude Data.Aeson Data.Time> decode (encode [x]) :: Maybe [UTCTime]
Just [2013-10-17 10:06:59.542 UTC]

请注意黑线码头中的陷阱"部分:

Note the "pitfalls" section in the haddocks:

...

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utcTime