在hadoop中使用map reduce读取文件

Question

我正在尝试以 map reduce 形式编写 java 代码，它在 Eclipse 中运行，但是当我尝试以 map reduce 形式实现时，我收到了这个错误，请帮助我这个错误是什么意思以及如何解决这个问题

16/07/15 14:05:17 INFO Configuration.deprecation: session.id is deprecated. Instead, use dfs.metrics.session-id
16/07/15 14:05:17 INFO jvm.JvmMetrics: Initializing JVM Metrics with processName=JobTracker, sessionId=
16/07/15 14:05:17 INFO jvm.JvmMetrics: Cannot initialize JVM Metrics with processName=JobTracker, sessionId= - already initialized
16/07/15 14:05:18 WARN mapreduce.JobSubmitter: Hadoop command-line option parsing not performed. Implement the Tool interface and execute your application with ToolRunner to remedy this.
16/07/15 14:05:18 INFO mapred.FileInputFormat: Total input paths to process : 2
16/07/15 14:05:18 INFO mapreduce.JobSubmitter: Cleaning up the staging area file:/app/hadoop/tmp/mapred/staging/hadoop1148163758/.staging/job_local1148163758_0001
Exception in thread "main" java.io.IOException: Not a file: hdfs://localhost:54310/TcTest/NewTest
    at org.apache.hadoop.mapred.FileInputFormat.getSplits(FileInputFormat.java:320)
    at org.apache.hadoop.mapreduce.JobSubmitter.writeOldSplits(JobSubmitter.java:624)
    at org.apache.hadoop.mapreduce.JobSubmitter.writeSplits(JobSubmitter.java:616)
    at org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal(JobSubmitter.java:492)
    at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1296)
    at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1293)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:415)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1628)
    at org.apache.hadoop.mapreduce.Job.submit(Job.java:1293)
    at org.apache.hadoop.mapred.JobClient$1.run(JobClient.java:562)
    at org.apache.hadoop.mapred.JobClient$1.run(JobClient.java:557)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:415)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1628)
    at org.apache.hadoop.mapred.JobClient.submitJobInternal(JobClient.java:557)
    at org.apache.hadoop.mapred.JobClient.submitJob(JobClient.java:548)
    at org.apache.hadoop.mapred.JobClient.runJob(JobClient.java:833)
    at TextClassification.run(TextClassification.java:38)
    at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
    at TextClassification.main(TextClassification.java:43)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.apache.hadoop.util.RunJar.run(RunJar.java:221)
    at org.apache.hadoop.util.RunJar.main(RunJar.java:136)

Answer 1

您需要提供输入文件的完整路径作为程序的参数。右键单击程序-->运行配置-->参数

在此之前，您需要从 hadoop-version/share/hadoop 文件夹中添加一些 jar 文件。关于如何在本地模式下通过 eclipse 运行 map reduce 程序的完整详细信息，您可以参考下面的博客。

https://acadgild.com/blog/running-mapreduce-in-local-mode-2/