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錯誤：[cat：檔案不存在] 我無法在 14.04 中開啟 hadoop 輸出文件

tag-icon • tag-icon 14.04 filesystem hadoop cat
錯誤：[cat：檔案不存在] 我無法在 14.04 中開啟 hadoop 輸出文件

我已經在我的系統（14.04）中安裝了hadoop-1.0.3，然後本教程。

我成功地運行了一個範例 mapreduce 程式來進行字數統計，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

當我檢查輸出檔案時，它存在於輸出資料夾中，

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 超級群組 880838 2014-06-17 15:26 /user/hadoopuser/SampleOutput/part-r-00000

我嘗試使用以下命令打開它，

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

但我得到的結果如下，

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

請給我一個解決方案。預先感謝。

答案1

檢查檔案名稱。它是五個 0，而不是四個。

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

答案2

所以我意識到答案已經被接受，但這是發生在我身上時的解決方案（以防萬一其他人看到這個線程）。

太長了；確保您的 hadoop 目錄中沒有任何衝突的資料夾名稱（對我來說是 /usr/local/hadoop）。

當我產生輸出時，我將其放在名為“output/”的資料夾中，但是在此程式之前，我還有另一個程式也在寫入輸出，並且我已將輸出資料保存在我的hadoop 目錄中專門名為「output」的資料夾中。這給我帶來了問題，因為即使我運行時該資料夾沒有顯示bin/hadoop fs -ls，該命令bin/hadoop fs -cat output/*實際上是在我之前生成的資料夾中搜索，而不是在我剛剛運行的程式的輸出中搜索。使用 刪除該輸出目錄後rm -rf output/，問題就消失了。

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