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错误：[cat：文件不存在] 我无法在 14.04 中打开 Hadoop 输出文件

tag-icon • tag-icon 14.04 filesystem hadoop cat
错误：[cat：文件不存在] 我无法在 14.04 中打开 Hadoop 输出文件

我已经在我的系统（14.04）中安装了 hadoop-1.0.3，然后本教程。

我成功运行了一个用于 wordcount 的示例 mapreduce 程序，如下所示，

hadoopuser@arul-PC:/usr/local/hadoop$ bin/hadoop jar hadoop*examples*.jar wordcount /user/hadoopuser/SampleData /user/hadoopuser/SampleOutput
14/06/17 15:25:45 INFO input.FileInputFormat: Total input paths to process : 3
14/06/17 15:25:45 INFO util.NativeCodeLoader: Loaded the native-hadoop library
14/06/17 15:25:45 WARN snappy.LoadSnappy: Snappy native library not loaded
14/06/17 15:25:45 INFO mapred.JobClient: Running job: job_201406171444_0002
14/06/17 15:25:46 INFO mapred.JobClient:  map 0% reduce 0%
14/06/17 15:26:04 INFO mapred.JobClient:  map 66% reduce 0%
14/06/17 15:26:13 INFO mapred.JobClient:  map 100% reduce 0%
14/06/17 15:26:16 INFO mapred.JobClient:  map 100% reduce 22%
14/06/17 15:26:28 INFO mapred.JobClient:  map 100% reduce 100%
14/06/17 15:26:33 INFO mapred.JobClient: Job complete: job_201406171444_0002
14/06/17 15:26:33 INFO mapred.JobClient: Counters: 29
14/06/17 15:26:33 INFO mapred.JobClient:   Job Counters 
14/06/17 15:26:33 INFO mapred.JobClient:     Launched reduce tasks=1
14/06/17 15:26:33 INFO mapred.JobClient:     SLOTS_MILLIS_MAPS=33037
14/06/17 15:26:33 INFO mapred.JobClient:     Total time spent by all reduces waiting after reserving slots (ms)=0
14/06/17 15:26:33 INFO mapred.JobClient:     Total time spent by all maps waiting after reserving slots (ms)=0
14/06/17 15:26:33 INFO mapred.JobClient:     Launched map tasks=3
14/06/17 15:26:33 INFO mapred.JobClient:     Data-local map tasks=3
14/06/17 15:26:33 INFO mapred.JobClient:     SLOTS_MILLIS_REDUCES=21208
14/06/17 15:26:33 INFO mapred.JobClient:   File Output Format Counters 
14/06/17 15:26:33 INFO mapred.JobClient:     Bytes Written=880838
14/06/17 15:26:33 INFO mapred.JobClient:   FileSystemCounters
14/06/17 15:26:33 INFO mapred.JobClient:     FILE_BYTES_READ=2214875
14/06/17 15:26:33 INFO mapred.JobClient:     HDFS_BYTES_READ=3671899
14/06/17 15:26:33 INFO mapred.JobClient:     FILE_BYTES_WRITTEN=3775759
14/06/17 15:26:33 INFO mapred.JobClient:     HDFS_BYTES_WRITTEN=880838
14/06/17 15:26:33 INFO mapred.JobClient:   File Input Format Counters 
14/06/17 15:26:33 INFO mapred.JobClient:     Bytes Read=3671523
14/06/17 15:26:33 INFO mapred.JobClient:   Map-Reduce Framework
14/06/17 15:26:33 INFO mapred.JobClient:     Map output materialized bytes=1474367
14/06/17 15:26:33 INFO mapred.JobClient:     Map input records=77931
14/06/17 15:26:33 INFO mapred.JobClient:     Reduce shuffle bytes=1207341
14/06/17 15:26:33 INFO mapred.JobClient:     Spilled Records=255966
14/06/17 15:26:33 INFO mapred.JobClient:     Map output bytes=6076101
14/06/17 15:26:33 INFO mapred.JobClient:     Total committed heap usage (bytes)=517210112
14/06/17 15:26:33 INFO mapred.JobClient:     CPU time spent (ms)=11530
14/06/17 15:26:33 INFO mapred.JobClient:     Combine input records=629172
14/06/17 15:26:33 INFO mapred.JobClient:     SPLIT_RAW_BYTES=376
14/06/17 15:26:33 INFO mapred.JobClient:     Reduce input records=102324
14/06/17 15:26:33 INFO mapred.JobClient:     Reduce input groups=82335
14/06/17 15:26:33 INFO mapred.JobClient:     Combine output records=102324
14/06/17 15:26:33 INFO mapred.JobClient:     Physical memory (bytes) snapshot=589725696
14/06/17 15:26:33 INFO mapred.JobClient:     Reduce output records=82335
14/06/17 15:26:33 INFO mapred.JobClient:     Virtual memory (bytes) snapshot=1862012928
14/06/17 15:26:33 INFO mapred.JobClient:     Map output records=629172

当我检查输出文件时，它存在于输出文件夹中，

hadoopuser@arul-PC:/usr/local/hadoop$ bin/hadoop dfs -ls /user/hadoopuser/SampleOutput
Found 3 items
-rw-r--r--   1 hadoopuser supergroup          0 2014-06-17 15:26 /user/hadoopuser/SampleOutput/_SUCCESS
drwxr-xr-x   - hadoopuser supergroup          0 2014-06-17 15:25 /user/hadoopuser/SampleOutput/_logs

-rw-r--r-- 1 hadoopuser 超级组 880838 2014-06-17 15:26 /user/hadoopuser/SampleOutput/part-r-00000

我尝试使用以下命令打开它，

hadoopuser@avvenire-PC:/usr/local/hadoop$ bin/hadoop dfs -cat /user/hadoopuser/SampleOutput/part-r-0000

但我得到的结果如下，

cat: File does not exist: /user/hadoopuser/SampleOutput/part-r-0000

请提供解决方案。提前致谢。

答案1

检查文件名。它是五个 0，而不是四个。

bin/hadoop dfs -cat /用户/hadoopuser/SampleOutput/part-r-00000

答案2

所以我意识到答案已经被接受了，但是当它发生在我身上时，这是解决方案（以防其他人看到这个帖子）。

TLDR；确保您的 hadoop 目录中没有任何冲突的文件夹名称（对我来说它是 /usr/local/hadoop）。

当我生成输出时，我将其放在名为 output/ 的文件夹中，但是在此程序之前，我还有另一个程序也在写入输出，并且我将输出数据保存在 hadoop 目录中名为 output 的文件夹中。这给我带来了问题，因为即使在我运行 时该文件夹没有出现bin/hadoop fs -ls，但命令bin/hadoop fs -cat output/*实际上是在搜索我之前生成的文件夹，而不是我刚刚运行的程序的输出。使用 删除该输出目录后rm -rf output/，问题就消失了。

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