How do I convert column of unix epoch to Date in Apache spark DataFrame using Java? -

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i have json data file contain 1 property [creationdate] unix epoc in "long" number type. apache spark dataframe schema below:

 root   |-- creationdate: long (nullable = true)   |-- id: long (nullable = true)   |-- posttypeid: long (nullable = true)  |-- tags: array (nullable = true)  |    |-- element: string (containsnull = true)  |-- title: string (nullable = true)  |-- viewcount: long (nullable = true)

i groupby "creationdata_year" need "creationdate".

what's easiest way kind of convert in dataframe using java?

after checking spark dataframe api , sql function, come out below snippet:

 dateframe df = sqlcontext.read().json("my_json_data_file");  dataframe df_dateconverted = df.withcolumn("creationdt", from_unixtime(stackoverflow_tags.col("creationdate").divide(1000)));

the reason why "creationdate" column divided "1000" cause timeunit different. orgin "creationdate" unix epoch in "milli-second", spark sql "from_unixtime" designed handle unix epoch in "second".


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