解决 pyspark 中调用 show() 函数报 Unicod

错误信息：

Traceback (most recent call last):
  File "/data/app/ald_spark/aldstat_daily.py", line 177, in <module>
    calc_convert_rate3(spark)
  File "/data/app/ald_spark/aldstat_daily.py", line 77, in calc_convert_rate3
    event_logs_df.show();
  File "/data/app/ald_spark/spark/python/lib/pyspark.zip/pyspark/sql/dataframe.py", line 287, in show
UnicodeEncodeError: 'ascii' codec can't encode characters in position 822-825: ordinal not in range(128)

解决方法，提交脚本之前，设置环境变量：

export PYTHONIOENCODING=utf8