If you use Hadoop-related things in the program, such as writing files to HDFS, you will encounter the following exception: The 
reason for this problem is not a program error, but the use of Hadoop-related services. The solution:
configure HADOOP_HOME environment variable
If this problem occurs, it is because the hadoop permission on windows is not enough.
Exception in thread "main" java.lang.UnsatisfiedLinkError: org.apache.hadoop.io.nativeio.NativeIO$Windows.access0(Ljava/lang/String;I)Z
at org.apache.hadoop.io.nativeio.NativeIO$Windows.access0(Native Method)
at org.apache.hadoop.io.nativeio.NativeIO$Windows.access(NativeIO.java:645)
at org.apache.hadoop.fs.FileUtil.canRead(FileUtil.java:1230)
at org.apache.hadoop.fs.FileUtil.list(FileUtil.java:1435)
at org.apache.hadoop.fs.RawLocalFileSystem.listStatus(RawLocalFileSystem.java:493)
at org.apache.hadoop.fs.FileSystem.listStatus(FileSystem.java:1868)
at org.apache.hadoop.fs.FileSystem.listStatus(FileSystem.java:1910)
at org.apache.hadoop.fs.FileSystem$4.<init>(FileSystem.java:2072)
The solution is to copy hadoop.dll in the hadoop bin folder installed on windows to the C:\Windows\System32 folder.
If this problem still occurs, it is because there is no C++ dependent library locally.