我在运行Hadoop作业时遇到问题,即使文件存在,但在尝试从分布式缓存中检索文件时收到FileNotFoundException。当我在本地文件系统上运行它时,它可以工作。从Hadoop分布式缓存中读取文件时FileNotFoundExcepton
集群托管在Amazon Web Services上,使用Hadoop版本1.0.4和Java版本1.7。我对集群没有任何控制权,也没有对集群的设置。
在主函数中,我将文件添加到分布式缓存中。这似乎工作正常。我认为,至少它不会抛出任何例外。
....
JobConf conf = new JobConf(Driver.class);
conf.setJobName("mean");
conf.set("lookupfile", args[2]);
Job job = new Job(conf);
DistributedCache.addCacheFile(new Path(args[2]).toUri(), conf);
...
在设置功能被称为地图之前,我创建的文件的路径,并调用该文件加载到一个哈希表的功能。
Configuration conf = context.getConfiguration();
String inputPath = conf.get("lookupfile");
Path dataFile = new Path(inputPath);
loadHashMap(dataFile, context);
加载哈希映射的函数的第一行发生异常。
brReader = new BufferedReader(new FileReader(filePath.toString()));
我开始这样的工作。
hadoop jar Driver.jar Driver /tmp/input output /tmp/DATA.csv
我收到以下错误
Error: Found class org.apache.hadoop.mapreduce.Counter, but interface was expected
attempt_201410300715_0018_m_000000_0: java.io.FileNotFoundException: /tmp/DATA.csv (No such file or directory)
attempt_201410300715_0018_m_000000_0: at java.io.FileInputStream.open(Native Method)
attempt_201410300715_0018_m_000000_0: at java.io.FileInputStream.<init>(FileInputStream.java:146)
attempt_201410300715_0018_m_000000_0: at java.io.FileInputStream.<init>(FileInputStream.java:101)
attempt_201410300715_0018_m_000000_0: at java.io.FileReader.<init>(FileReader.java:58)
attempt_201410300715_0018_m_000000_0: at Map.loadHashMap(Map.java:49)
attempt_201410300715_0018_m_000000_0: at Map.setup(Map.java:98)
attempt_201410300715_0018_m_000000_0: at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:145)
attempt_201410300715_0018_m_000000_0: at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:771)
attempt_201410300715_0018_m_000000_0: at org.apache.hadoop.mapred.MapTask.run(MapTask.java:375)
attempt_201410300715_0018_m_000000_0: at org.apache.hadoop.mapred.Child$4.run(Child.java:259)
attempt_201410300715_0018_m_000000_0: at java.security.AccessController.doPrivileged(Native Method)
attempt_201410300715_0018_m_000000_0: at javax.security.auth.Subject.doAs(Subject.java:415)
attempt_201410300715_0018_m_000000_0: at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1140)
attempt_201410300715_0018_m_000000_0: at org.apache.hadoop.mapred.Child.main(Child.java:253)
14/11/01 02:12:49 INFO mapred.JobClient: Task Id : attempt_201410300715_0018_m_000001_0, Status : FAILED
我已经验证该文件存在,无论是在HDFS和本地文件系统上。
[email protected]:~$ hadoop fs -ls /tmp
Found 2 items
drwxr-xr-x - hadoop supergroup 0 2014-10-30 11:19 /tmp/input
-rw-r--r-- 1 hadoop supergroup 428796 2014-10-30 11:19 /tmp/DATA.csv
[email protected]:~$ ls -al /tmp/
-rw-r--r-- 1 hadoop hadoop 428796 Oct 30 11:30 DATA.csv
我真的不明白这里有什么问题。例外列出了该文件的正确路径。我已经验证该文件存在于HDFS和本地文件系统上。有什么我在这里失踪?