hadoop显示hdfs的文件内容

1.Exception in thread "main" java.net.ConnectException: Call to master/192.168.1.101:9000 failed on connection exception: java.net.ConnectException: 拒绝连接

        at org.apache.hadoop.ipc.Client.wrapException(Client.java:1142)

        at org.apache.hadoop.ipc.Client.call(Client.java:1118)

        at org.apache.hadoop.ipc.RPC$Invoker.invoke(RPC.java:229)

        at com.sun.proxy.$Proxy1.getProtocolVersion(Unknown Source)

        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.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:85)

hadoop的hdfs没启动，

启动hdfs：到bin目录执行start-dfs.sh

执行命令读取文件内容：

报错[root@localhost bin]# ../bin/hadoop URLCat hdfs://192.168.1.101:9000/root/in/test1.txt

Exception in thread "main" java.io.FileNotFoundException: File does not exist: /root/in/test1.txt

        at org.apache.hadoop.hdfs.DFSClient$DFSInputStream.fetchLocatedBlocks(DFSClient.java:2006)

        at org.apache.hadoop.hdfs.DFSClient$DFSInputStream.openInfo(DFSClient.java:1975)

        at org.apache.hadoop.hdfs.DFSClient$DFSInputStream.<init>(DFSClient.java:1967)

        at org.apache.hadoop.hdfs.DFSClient.open(DFSClient.java:735)

        at org.apache.hadoop.hdfs.DistributedFileSystem.open(DistributedFileSystem.java:165)

        at org.apache.hadoop.fs.FileSystem.open(FileSystem.java:436)

        at org.apache.hadoop.fs.FsUrlConnection.connect(FsUrlConnection.java:46)

        at org.apache.hadoop.fs.FsUrlConnection.getInputStream(FsUrlConnection.java:56)

        at java.net.URL.openStream(URL.java:1037)

        at URLCat.main(URLCat.java:15)

其实 文件test1.txt是存在的。

 

原因：没有把本地文件放到hdfs文件系统内。所以需要本地文件通过hadoop的命令存放到hdfs上。

（1）.创建本地文件，当前目录是/usr/local/hadoop1.2.1目录

 mkdir input  //创建input目录

 cd input     //到input目录上

 echo "hello world ">test1.txt  //字符串内不能包含感叹号（!），bash命令无法解析

 echo "hello hadoop">test2.txt

（2）.创建好文件后，通过hadoop命令本地文件放到hdfs系统上,当前目录：usr/local/hadoop1.2.1目录

 bin/hadoop fs -put input  ./in  //放到hdf上

 bin/hadoop fs -ls     //检查hdfs文件

运行结果为：

 Found 1 items

 drwxr-xr-x   - root supergroup          0 2015-05-17 01:11 /user/root/in

 

 bin/hadoop fs -cat ./in/test1.txt  //查看文件内容

 

（3）.通过hadoop提供的例子，读取刚上传的hdf文件的内容，统计单词

  bin/hadoop jar hadoop-examples-1.2.1.jar  wordcount in out  //统计in目录下，文件内容的单词数量

运行结果为：

15/05/17 01:13:40 INFO input.FileInputFormat: Total input paths to process : 2

15/05/17 01:13:40 INFO util.NativeCodeLoader: Loaded the native-hadoop library

15/05/17 01:13:40 WARN snappy.LoadSnappy: Snappy native library not loaded

15/05/17 01:13:41 INFO mapred.JobClient: Running job: job_201505170049_0001

15/05/17 01:13:42 INFO mapred.JobClient:  map 0% reduce 0%

15/05/17 01:13:52 INFO mapred.JobClient:  map 100% reduce 0%

15/05/17 01:14:28 INFO mapred.JobClient:  map 100% reduce 100%

15/05/17 01:14:31 INFO mapred.JobClient: Job complete: job_201505170049_0001

15/05/17 01:14:31 INFO mapred.JobClient: Counters: 29

15/05/17 01:14:31 INFO mapred.JobClient:   Job Counters 

15/05/17 01:14:31 INFO mapred.JobClient:     Launched reduce tasks=1

15/05/17 01:14:31 INFO mapred.JobClient:     SLOTS_MILLIS_MAPS=14618

15/05/17 01:14:31 INFO mapred.JobClient:     Total time spent by all reduces waiting after reserving slots (ms)=0

15/05/17 01:14:31 INFO mapred.JobClient:     Total time spent by all maps waiting after reserving slots (ms)=0

15/05/17 01:14:31 INFO mapred.JobClient:     Launched map tasks=2

15/05/17 01:14:31 INFO mapred.JobClient:     Data-local map tasks=2

15/05/17 01:14:31 INFO mapred.JobClient:     SLOTS_MILLIS_REDUCES=27918

15/05/17 01:14:31 INFO mapred.JobClient:   File Output Format Counters 

15/05/17 01:14:31 INFO mapred.JobClient:     Bytes Written=25

15/05/17 01:14:31 INFO mapred.JobClient:   FileSystemCounters

15/05/17 01:14:31 INFO mapred.JobClient:     FILE_BYTES_READ=55

15/05/17 01:14:31 INFO mapred.JobClient:     HDFS_BYTES_READ=241

15/05/17 01:14:31 INFO mapred.JobClient:     FILE_BYTES_WRITTEN=173312

15/05/17 01:14:31 INFO mapred.JobClient:     HDFS_BYTES_WRITTEN=25

15/05/17 01:14:31 INFO mapred.JobClient:   File Input Format Counters 

15/05/17 01:14:31 INFO mapred.JobClient:     Bytes Read=25

15/05/17 01:14:31 INFO mapred.JobClient:   Map-Reduce Framework

15/05/17 01:14:31 INFO mapred.JobClient:     Map output materialized bytes=61

15/05/17 01:14:31 INFO mapred.JobClient:     Map input records=2

15/05/17 01:14:31 INFO mapred.JobClient:     Reduce shuffle bytes=61

15/05/17 01:14:31 INFO mapred.JobClient:     Spilled Records=8

15/05/17 01:14:31 INFO mapred.JobClient:     Map output bytes=41

15/05/17 01:14:31 INFO mapred.JobClient:     Total committed heap usage (bytes)=415969280

15/05/17 01:14:31 INFO mapred.JobClient:     CPU time spent (ms)=1550

15/05/17 01:14:31 INFO mapred.JobClient:     Combine input records=4

15/05/17 01:14:31 INFO mapred.JobClient:     SPLIT_RAW_BYTES=216

15/05/17 01:14:31 INFO mapred.JobClient:     Reduce input records=4

15/05/17 01:14:31 INFO mapred.JobClient:     Reduce input groups=3

15/05/17 01:14:31 INFO mapred.JobClient:     Combine output records=4

15/05/17 01:14:31 INFO mapred.JobClient:     Physical memory (bytes) snapshot=318287872

15/05/17 01:14:31 INFO mapred.JobClient:     Reduce output records=3

15/05/17 01:14:31 INFO mapred.JobClient:     Virtual memory (bytes) snapshot=1041612800

15/05/17 01:14:31 INFO mapred.JobClient:     Map output records=4

[root@backup01 hadoop-1.2.1]# bin/hadoop fs -ls

Found 2 items

drwxr-xr-x   - root supergroup          0 2015-05-17 01:11 /user/root/in

drwxr-xr-x   - root supergroup          0 2015-05-17 01:14 /user/root/out

[root@backup01 hadoop-1.2.1]# bin/hadoop fs -ls ./out

Found 3 items

-rw-r--r--   1 root supergroup          0 2015-05-17 01:14 /user/root/out/_SUCCESS

drwxr-xr-x   - root supergroup          0 2015-05-17 01:13 /user/root/out/_logs

-rw-r--r--   1 root supergroup         25 2015-05-17 01:14 /user/root/out/part-r-00000

[root@backup01 hadoop-1.2.1]# bin/hadoop fs -cat ./out/part-r-00000

hadoop  1

hello   2

world   1

 

 

 

 

 

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