MapReduce本地跑wordcount测试，报以下错误：
Exception in thread "main" java.lang.UnsatisfiedlinkError: 'boolean org.apache.hadoop.io.nativeio.NativeIO$Windows.access0(java.lang.String, int)' at org.apache.hadoop.io.nativeio.NativeIO$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.(FileSystem.java:2072) at org.apache.hadoop.fs.FileSystem.listLocatedStatus(FileSystem.java:2071) at org.apache.hadoop.fs.ChecksumFileSystem.listLocatedStatus(ChecksumFileSystem.java:700) at org.apache.hadoop.mapreduce.lib.input.FileInputFormat.singleThreadedListStatus(FileInputFormat.java:312) at org.apache.hadoop.mapreduce.lib.input.FileInputFormat.listStatus(FileInputFormat.java:274) at org.apache.hadoop.mapreduce.lib.input.FileInputFormat.getSplits(FileInputFormat.java:396) at org.apache.hadoop.mapreduce.JobSubmitter.writeNewSplits(JobSubmitter.java:310) at org.apache.hadoop.mapreduce.JobSubmitter.writeSplits(JobSubmitter.java:327) at org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal(JobSubmitter.java:200) at org.apache.hadoop.mapreduce.Job$11.run(Job.java:1570) at org.apache.hadoop.mapreduce.Job$11.run(Job.java:1567) at java.base/java.security.AccessController.doPrivileged(AccessController.java:691) at java.base/javax.security.auth.Subject.doAs(Subject.java:427) at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1730) at org.apache.hadoop.mapreduce.Job.submit(Job.java:1567) at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:1588) at com.atguigu.mapreduce.wordcount.WordCountDriver.main(WordCountDriver.java:39)
解决方法：把hadoop.dll复制到System32
