IDEA运行时出现的错误：java.io.FileNotFoundException: HADOOP_HOME and hadoop.home.dir are unset._exception in thread "main" java.lang.runtimeexcept

注：本人使用的hadoop版本为hadoop-3.3.4

错误信息：

Exception in thread "main" java.lang.RuntimeException: java.io.FileNotFoundException: java.io.FileNotFoundException: HADOOP_HOME and hadoop.home.dir are unset. -see https://wiki.apache.org/hadoop/WindowsProblems
	at org.apache.hadoop.util.Shell.getWinUtilsPath(Shell.java:735)
	at org.apache.hadoop.util.Shell.getSetPermissionCommand(Shell.java:270)
	at org.apache.hadoop.util.Shell.getSetPermissionCommand(Shell.java:286)
	at org.apache.hadoop.fs.RawLocalFileSystem.setPermission(RawLocalFileSystem.java:978)
	at org.apache.hadoop.fs.RawLocalFileSystem.mkOneDirWithMode(RawLocalFileSystem.java:660)
	at org.apache.hadoop.fs.RawLocalFileSystem.mkdirsWithOptionalPermission(RawLocalFileSystem.java:700)
	at org.apache.hadoop.fs.RawLocalFileSystem.mkdirs(RawLocalFileSystem.java:672)
	at org.apache.hadoop.fs.RawLocalFileSystem.mkdirsWithOptionalPermission(RawLocalFileSystem.java:699)
	at org.apache.hadoop.fs.RawLocalFileSystem.mkdirs(RawLocalFileSystem.java:677)
	at org.apache.hadoop.fs.FilterFileSystem.mkdirs(FilterFileSystem.java:336)
	at org.apache.hadoop.mapreduce.JobSubmissionFiles.getStagingDir(JobSubmissionFiles.java:162)
	at org.apache.hadoop.mapreduce.JobSubmissionFiles.getStagingDir(JobSubmissionFiles.java:113)
	at org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal(JobSubmitter.java:148)
	at org.apache.hadoop.mapreduce.Job$11.run(Job.java:1571)
	at org.apache.hadoop.mapreduce.Job$11.run(Job.java:1568)
	at java.security.AccessController.doPrivileged(Native Method)
	at javax.security.auth.Subject.doAs(Subject.java:422)
	at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1878)
	at org.apache.hadoop.mapreduce.Job.submit(Job.java:1568)
	at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:1589)
	at net.army.mr.WordCountDriver.main(WordCountDriver.java:59)
Caused by: java.io.FileNotFoundException: java.io.FileNotFoundException: HADOOP_HOME and hadoop.home.dir are unset. -see https://wiki.apache.org/hadoop/WindowsProblems
	at org.apache.hadoop.util.Shell.fileNotFoundException(Shell.java:547)
	at org.apache.hadoop.util.Shell.getHadoopHomeDir(Shell.java:568)
	at org.apache.hadoop.util.Shell.getQualifiedBin(Shell.java:591)
	at org.apache.hadoop.util.Shell.<clinit>(Shell.java:688)
	at org.apache.hadoop.util.StringUtils.<clinit>(StringUtils.java:79)
	at org.apache.hadoop.cf.Configuration.getBoolean(Configuration.java:1712)
	at org.apache.hadoop.security.SecurityUtil.setConfigurationInternal(SecurityUtil.java:99)
	at org.apache.hadoop.security.SecurityUtil.<clinit>(SecurityUtil.java:88)
	at org.apache.hadoop.security.UserGroupInformation.initialize(UserGroupInformation.java:312)
	at org.apache.hadoop.security.UserGroupInformation.ensureInitialized(UserGroupInformation.java:300)
	at org.apache.hadoop.security.UserGroupInformation.getCurrentUser(UserGroupInformation.java:575)
	at org.apache.hadoop.mapreduce.task.JobContextImpl.<init>(JobContextImpl.java:72)
	at org.apache.hadoop.mapreduce.Job.<init>(Job.java:152)
	at org.apache.hadoop.mapreduce.Job.getInstance(Job.java:195)
	at net.army.mr.WordCountDriver.main(WordCountDriver.java:30)
Caused by: java.io.FileNotFoundException: HADOOP_HOME and hadoop.home.dir are unset.
	at org.apache.hadoop.util.Shell.checkHadoopHomeInner(Shell.java:467)
	at org.apache.hadoop.util.Shell.checkHadoopHome(Shell.java:438)
	at org.apache.hadoop.util.Shell.<clinit>(Shell.java:515)
	... 11 more

Process finished with exit code 1
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解决方法：

1.在百度网盘下载所需文件hadoop.dll

链接：https://pan.baidu.com/s/1-6G0YG4JemoVL1JYwH-ebA
提取码：o8zg

2.将hadoop.dll文件拷贝到 /windows/system32 目录下

3.重新打开IDEA程序，运行代码