此代碼來自 Hadoop 和 Spark 課程。我在 VM（HDP 沙箱）上運(yùn)行它[root@sandbox-hdp Lesson-5.3_hadoop-grep]# javac -classpath /usr/lib/hadoop/hadoop-core.jar -d Grep_classes Grep.javaGrep.java:22: error: package org.apache.hadoop.conf does not existimport org.apache.hadoop.conf.Configuration;                             ^Grep.java:23: error: package org.apache.hadoop.conf does not existimport org.apache.hadoop.conf.Configured;                             ^Grep.java:24: error: package org.apache.hadoop.fs does not existimport org.apache.hadoop.fs.FileSystem;                           ^Grep.java:25: error: package org.apache.hadoop.fs does not existimport org.apache.hadoop.fs.Path;我是 Hadoop 新手，如何定義類路徑？如果我嘗試hadoop classpath輸出/usr/hdp/3.0.1.0-187/hadoop/conf:/usr/hdp/3.0.1.0-187/hadoop/lib/*:/usr/hdp/3.0.1.0-187/hadoop/.//*:/usr/hdp/3.0.1.0-187/hadoop-hdfs/./:/usr/hdp/3.0.1.0-187/hadoop-hdfs/lib/*:/usr/hdp/3.0.1.0-187/hadoop-hdfs/.//*:/usr/hdp/3.0.1.0-187/hadoop-mapreduce/lib/*:/usr/hdp/3.0.1.0-187/hadoop-mapreduce/.//*:/usr/hdp/3.0.1.0-187/hadoop-yarn/./:/usr/hdp/3.0.1.0-187/hadoop-yarn/lib/*:/usr/hdp/3.0.1.0-187/hadoop-yarn/.//*:/usr/hdp/3.0.1.0-187/tez/*:/usr/hdp/3.0.1.0-187/tez/lib/*:/usr/hdp/3.0.1.0-187/tez/conf:/usr/hdp/3.0.1.0-187/tez/conf_llap:/usr/hdp/3.0.1.0-187/tez/doc:/usr/hdp/3.0.1.0-187/tez/hadoop-shim-0.9.1.3.0.1.0-187.jar:/usr/hdp/3.0.1.0-187/tez/hadoop-shim-2.8-0.9.1.3.0.1.0-187.jar如何更改 javac 行？