hadoop:Input path does not exist異常

（1）異常描述

當你在當前hadoop目錄下面建立一個input目錄，並cp某些檔案到裡面，開始執行：

[root@localhost hadoop-0.19.0]# bin/hadoop namenode -format

[root@localhost hadoop-0.19.0]# bin/start-all.sh

這時候，你認為input已經存在，應該可以執行wordcount任務了：

[root@localhost hadoop-0.19.0]# bin/hadoop jar hadoop-0.19.0-examples.jar wordcount input output

結果拋出一堆異常，資訊如下：

org.apache.hadoop.mapred.InvalidInputException: Input path does not exist: hdfs://localhost:9000/user/root/input
        at org.apache.hadoop.mapred.FileInputFormat.listStatus(FileInputFormat.java:179)
        at org.apache.hadoop.mapred.FileInputFormat.getSplits(FileInputFormat.java:190)
        at org.apache.hadoop.mapred.JobClient.submitJob(JobClient.java:782)
        at org.apache.hadoop.mapred.JobClient.runJob(JobClient.java:1127)
        at org.apache.hadoop.examples.WordCount.run(WordCount.java:149)
        at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
        at org.apache.hadoop.examples.WordCount.main(WordCount.java:155)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.apache.hadoop.util.ProgramDriver$ProgramDescription.invoke(ProgramDriver.java:68)
        at org.apache.hadoop.util.ProgramDriver.driver(ProgramDriver.java:141)
        at org.apache.hadoop.examples.ExampleDriver.main(ExampleDriver.java:61)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.apache.hadoop.util.RunJar.main(RunJar.java:165)
        at org.apache.hadoop.mapred.JobShell.run(JobShell.java:54)
        at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
        at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:79)
        at org.apache.hadoop.mapred.JobShell.main(JobShell.java:68)

上述異常，我類比的過程是：

[root@localhost hadoop-0.19.0]# bin/hadoop fs -rmr input
Deleted hdfs://localhost:9000/user/root/input

[root@localhost hadoop-0.19.0]# bin/hadoop fs -rmr output
Deleted hdfs://localhost:9000/user/root/output

因為之前我已經成功執行過一次。

（2）異常分析

應該不用多說了，是因為本地的input目錄並沒有上傳到HDFS上，所出現 org.apache.hadoop.mapred.InvalidInputException: Input path does not exist: hdfs://localhost:9000/user/root/input

在我的印象中，好像使用hadoop-0.16.4的時候，只要input目錄存在，是不用執行上傳命令，就可以啟動並執行，後期的版本是不行的。

只需要執行上傳的命令即可：

[root@localhost hadoop-0.19.0]# bin/hadoop fs -put input/ input