配置Spark時Error: A JNI error has occurred, please check your installation and try again

在Spark官網下載Spark時可以選擇下載帶Hadoop和不帶Hadoop的版本。
如果選擇下載不帶Hadoop的版本，需要在${SPARK_HOME}/conf/spark-env.sh中export環境變量SPARK_DIST_CLASSPATH，否則會在啓動時遇到A JNI error has occurred, please check your installation and try again；而下載帶Hadoop的Spark就不需要。

應該這樣配置SPARK_DIST_CLASSPATH：

### in conf/spark-env.sh ###

# If 'hadoop' binary is on your PATH
export SPARK_DIST_CLASSPATH=$(hadoop classpath)

# With explicit path to 'hadoop' binary
export SPARK_DIST_CLASSPATH=$(/path/to/hadoop/bin/hadoop classpath)

# Passing a Hadoop configuration directory
export SPARK_DIST_CLASSPATH=$(hadoop --config /path/to/configs classpath)

 
官方的說法戳這裏