解决Exception: org.apache.hadoop.io.nativeio.NativeIO$Windows.access0(Ljava/lang/String;I)Z 等一系列问题，ljavalangstring
一．简介
Windows下的 Eclipse上调试Hadoop2代码，所以我们在windows下的Eclipse配置hadoop-eclipse-plugin-2.6.0.jar插件，并在运行Hadoop代码时出现了一系列的问题，搞了好几天终于能运行起代码。接下来我们来看看问题并怎么解决，提供给跟我同样遇到的问题作为参考。
Hadoop2的WordCount.java统计代码如下：
import java.io.IOException;
import java.util.StringTokenizer;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
public class WordCount {
public static class TokenizerMapper
extends Mapper{
private final static IntWritable one = new IntWritable(1);
private Text word = new Text();
public void map(Object key, Text value, Context context
) throws IOException, InterruptedException {
StringTokenizer itr = new StringTokenizer(value.toString());
while (itr.hasMoreTokens()) {
word.set(itr.nextToken());
context.write(word, one);
}
}
}
public static class IntSumReducer
extends Reducer {
private IntWritable result = new IntWritable();
public void reduce(Text key, Iterable values,
Context context
) throws IOException, InterruptedException {
int sum = 0;
for (IntWritable val : values) {
sum += val.get();
}
result.set(sum);
context.write(key, result);
}
}
public static void main(String[] args) throws Exception {
Configuration conf = new Configuration();
Job job = Job.getInstance(conf, "word count");
job.setJarByClass(WordCount.class);
job.setMapperClass(TokenizerMapper.class);
job.setCombinerClass(IntSumReducer.class);
job.setReducerClass(IntSumReducer.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
FileInputFormat.addInputPath(job, new Path(args[0]));
FileOutputFormat.setOutputPath(job, new Path(args[1]));
System.exit(job.waitForCompletion(true) ? 0 : 1);
}
}
问题一.An internal error occurred during: "Map/Reducelocation status updater".java.lang.NullPointerException
我们hadoop-eclipse-plugin-2.6.0.jar放到Eclipse的plugins目录下，我们的Eclipse目录是F:\tool\eclipse-jee-juno-SR2\eclipse-jee-juno-SR2\plugins，重启一下Eclipse，然后，打开Window-->Preferens，可以看到Hadoop Map/Reduc选项，然后点击出现了An internal error occurredduring: "Map/Reduce location status updater".java.lang.NullPointerException，如图所示：
解决：
我们发现刚配置部署的Hadoop2还没创建输入和输出目录，先在hdfs上建个文件夹 。
#bin/hdfs dfs -mkdir –p /user/root/input
#bin/hdfs dfs -mkdir -p /user/root/output
我们在Eclipse的DFS Locations目录下看到我们这两个目录，如图所示：
问题二.Exception in thread "main" java.lang.NullPointerException atjava.lang.ProcessBuilder.start(Unknown Source)
运行Hadoop2的WordCount.java代码时出现了这样错误，
log4j:WARNPlease initialize the log4j system properly.
log4j:WARN Seehttp://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
Exception in thread "main" java.lang.NullPointerException
atjava.lang.ProcessBuilder.start(Unknown Source)
atorg.apache.hadoop.util.Shell.runCommand(Shell.java:482)
atorg.apache.hadoop.util.Shell.run(Shell.java:455)
atorg.apache.hadoop.util.Shell$ShellCommandExecutor.execute(Shell.java:715)
atorg.apache.hadoop.util.Shell.execCommand(Shell.java:808)
atorg.apache.hadoop.util.Shell.execCommand(Shell.java:791)
at
分析：
下载Hadoop2以上版本时，在Hadoop2的bin目录下没有winutils.exe
解决：
1.下载https://codeload.github.com/srccodes/hadoop-common-2.2.0-bin/zip/master下载hadoop-common-2.2.0-bin-master.zip，然后解压后，把hadoop-common-2.2.0-bin-master下的bin全部复制放到我们下载的Hadoop2的binHadoop2/bin目录下。如图所示：
2.Eclipse-》window-》Preferences 下的Hadoop Map/Peduce 把下载放在我们的磁盘的Hadoop目录引进来，如图所示：
3.Hadoop2配置变量环境HADOOP_HOME 和path，如图所示：
问题三.Exception in thread "main"java.lang.UnsatisfiedLinkError:org.apache.hadoop.io.nativeio.NativeIO$Windows.access0(Ljava/lang/String;I)Z
当我们解决了问题三时，在运行WordCount.java代码时，出现这样的问题
log4j:WARN No appenders could be found forlogger (org.apache.hadoop.metrics2.lib.MutableMetricsFactory).
log4j:WARN Please initialize the log4jsystem properly.
log4j:WARN Seehttp://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
Exception in thread "main"java.lang.UnsatisfiedLinkError:org.apache.hadoop.io.nativeio.NativeIO$Windows.access0(Ljava/lang/String;I)Z
atorg.apache.hadoop.io.nativeio.NativeIO$Windows.access0(Native Method)
atorg.apache.hadoop.io.nativeio.NativeIO$Windows.access(NativeIO.java:557)
atorg.apache.hadoop.fs.FileUtil.canRead(FileUtil.java:977)
atorg.apache.hadoop.util.DiskChecker.checkAccessByFileMethods(DiskChecker.java:187)
atorg.apache.hadoop.util.DiskChecker.checkDirAccess(DiskChecker.java:174)
atorg.apache.hadoop.util.DiskChecker.checkDir(DiskChecker.java:108)
atorg.apache.hadoop.fs.LocalDirAllocator$AllocatorPerContext.confChanged(LocalDirAllocator.java:285)
atorg.apache.hadoop.fs.LocalDirAllocator$AllocatorPerContext.getLocalPathForWrite(LocalDirAllocator.java:344)
atorg.apache.hadoop.fs.LocalDirAllocator.getLocalPathForWrite(LocalDirAllocator.java:150)
atorg.apache.hadoop.fs.LocalDirAllocator.getLocalPathForWrite(LocalDirAllocator.java:131)
atorg.apache.hadoop.fs.LocalDirAllocator.getLocalPathForWrite(LocalDirAllocator.java:115)
atorg.apache.hadoop.mapred.LocalDistributedCacheManager.setup(LocalDistributedCacheManager.java:131)
分析：
C:\Windows\System32下缺少hadoop.dll,把这个文件拷贝到C:\Windows\System32下面即可。
解决：
hadoop-common-2.2.0-bin-master下的bin的hadoop.dll放到C:\Windows\System32下，然后重启电脑，也许还没那么简单，还是出现这样的问题。
我们在继续分析：
我们在出现错误的的atorg.apache.hadoop.io.nativeio.NativeIO$Windows.access(NativeIO.java:557)我们来看这个类NativeIO的557行，如图所示：
Windows的唯一方法用于检查当前进程的请求，在给定的路径的访问权限，所以我们先给以能进行访问，我们自己先修改源代码，return true 时允许访问。我们下载对应hadoop源代码，hadoop-2.6.0-src.tar.gz解压，hadoop-2.6.0-src\hadoop-common-project\hadoop-common\src\main\java\org\apache\hadoop\io\nativeio下NativeIO.java 复制到对应的Eclipse的project，然后修改557行为return true如图所示：
问题四：org.apache.hadoop.security.AccessControlException: Permissiondenied: user=zhengcy, access=WRITE,inode="/user/root/output":root:supergroup:drwxr-xr-x
我们在执行运行WordCount.java代码时，出现这样的问题
2014-12-18 16:03:24,092 WARN (org.apache.hadoop.mapred.LocalJobRunner:560) - job_local374172562_0001 org.apache.hadoop.security.AccessControlException: Permission denied: user=zhengcy, access=WRITE, inode="/user/root/output":root:supergroup:drwxr-xr-x at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.checkFsPermission(FSPermissionChecker.java:271) at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.check(FSPermissionChecker.java:257) at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.check(FSPermissionChecker.java:238) at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.checkPermission(FSPermissionChecker.java:179) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkPermission(FSNamesystem.java:6512) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkPermission(FSNamesystem.java:6494) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkAncestorAccess(FSNamesystem.java:6446) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.mkdirsInternal(FSNamesystem.java:4248) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.mkdirsInt(FSNamesystem.java:4218) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.mkdirs(FSNamesystem.java:4191) at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.mkdirs(NameNodeRpcServer.java:813)
分析：
我们没权限访问output目录。
解决：
我们 在设置hdfs配置的目录是在hdfs-site.xml配置hdfs文件存放的地方，我在hadoop伪分布式部署那边有介绍过，我们在这边在复习一下，如图所示：
我们在这个etc/hadoop下的hdfs-site.xml添加
设置没有权限，不过我们在正式的 服务器上不能这样设置。
问题五：File/usr/root/input/file01._COPYING_ could only be replicated to 0 nodes instead ofminRepLication (=1) There are 0 datanode(s) running and no node(s) are excludedin this operation
如图所示：
分析：
我们在第一次执行#hadoop namenode –format 完然后在执行#sbin/start-all.sh
在执行#jps，能看到Datanode，在执行#hadoop namenode –format然后执行#jps这时看不到Datanode ,如图所示：
然后我们想把文本放到输入目录执行bin/hdfs dfs -put/usr/local/hadoop/hadoop-2.6.0/test/* /user/root/input 把/test/*文件上传到hdfs的/user/root/input中,出现这样的问题，
解决：
是我们执行太多次了hadoopnamenode –format，在创建了多个，我们对应的hdfs目录删除hdfs-site.xml配置的保存datanode和namenode目录。
修改配置文件，以下四个文件全部在hadoop目录下的etc/hadoop目录下
修改core-site.xml，如下：
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<
configuration
>
<
property
>
<
name
>fs.defaultFS
<
value
>hdfs://localhost:9000
|
修改hdfs-site.xml如下：
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<
configuration
>
<
property
>
<
name
>dfs.replication
<
value
>1
<
property
>
<
name
>dfs.namenode.name.dir
<
value
>file:/hadoop/data/dfs/namenode
<
property
>
<
name
>dfs.datanode.data.dir
<
value
>file:/hadoop/data/dfs/datanode
|
修改yarn-site.xml如下：
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<
configuration
>
<
property
>
<
name
>yarn.nodemanager.aux-services
<
value
>mapreduce_shuffle
<
property
>
<
name
>yarn.nodemanager.aux-services.mapreduce.shuffle.class
<
value
>org.apache.hadoop.mapred.ShuffleHandler
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修改mapred-site.xml如下：
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<
configuration
>
<
property
>
<
name
>mapreduce.framework.name
<
value
>yarn
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然后打开cmd，运行hadoop namenode -format命令,运行结果基本如下：
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Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.
C:\Users\abhijitg>
cd
c:\hadoop\bin
c:\hadoop\bin>hdfs namenode -
format
13
/11/03
18:07:47 INFO namenode.NameNode: STARTUP_MSG:
/************************************************************
STARTUP_MSG: Starting NameNode
STARTUP_MSG: host = ABHIJITG
/x
.x.x.x
STARTUP_MSG: args = [-
format
]
STARTUP_MSG: version = 2.2.0
STARTUP_MSG: classpath =
STARTUP_MSG: build = Unknown -r Unknown; compiled by ABHIJITG on 2013-11-01T13:42Z
STARTUP_MSG: java = 1.7.0_03
************************************************************/
Formatting using clusterid: CID-1af0bd9f-efee-4d4e-9f03-a0032c22e5eb
13
/11/03
18:07:48 INFO namenode.HostFileManager:
read
includes:
HostSet(
)
13
/11/03
18:07:48 INFO namenode.HostFileManager:
read
excludes:
HostSet(
)
13
/11/03
18:07:48 INFO blockmanagement.DatanodeManager: dfs.block.invalidate.limit=1000
13
/11/03
18:07:48 INFO util.GSet: Computing capacity
for
map BlocksMap
13
/11/03
18:07:48 INFO util.GSet: VM
type
= 64-bit
13
/11/03
18:07:48 INFO util.GSet: 2.0% max memory = 888.9 MB
13
/11/03
18:07:48 INFO util.GSet: capacity = 2^21 = 2097152 entries
13
/11/03
18:07:48 INFO blockmanagement.BlockManager: dfs.block.access.token.
enable
=
false
13
/11/03
18:07:48 INFO blockmanagement.BlockManager: defaultReplication = 1
13
/11/03
18:07:48 INFO blockmanagement.BlockManager: maxReplication = 512
13
/11/03
18:07:48 INFO blockmanagement.BlockManager: minReplication = 1
13
/11/03
18:07:48 INFO blockmanagement.BlockManager: maxReplicationStreams = 2
13
/11/03
18:07:48 INFO blockmanagement.BlockManager: shouldCheckForEnoughRacks =
false
13
/11/03
18:07:48 INFO blockmanagement.BlockManager: replicationRecheckInterval = 3000
13
/11/03
18:07:48 INFO blockmanagement.BlockManager: encryptDataTransfer =
false
13
/11/03
18:07:48 INFO namenode.FSNamesystem: fsOwner = ABHIJITG (auth:SIMPLE)
13
/11/03
18:07:48 INFO namenode.FSNamesystem: supergroup = supergroup
13
/11/03
18:07:48 INFO namenode.FSNamesystem: isPermissionEnabled =
true
13
/11/03
18:07:48 INFO namenode.FSNamesystem: HA Enabled:
false
13
/11/03
18:07:48 INFO namenode.FSNamesystem: Append Enabled:
true
13
/11/03
18:07:49 INFO util.GSet: Computing capacity
for
map INodeMap
13
/11/03
18:07:49 INFO util.GSet: VM
type
= 64-bit
13
/11/03
18:07:49 INFO util.GSet: 1.0% max memory = 888.9 MB
13
/11/03
18:07:49 INFO util.GSet: capacity = 2^20 = 1048576 entries
13
/11/03
18:07:49 INFO namenode.NameNode: Caching
file
names occuring
more
than 10
times
13
/11/03
18:07:49 INFO namenode.FSNamesystem: dfs.namenode.safemode.threshold-pct = 0.9990000128746033
13
/11/03
18:07:49 INFO namenode.FSNamesystem: dfs.namenode.safemode.min.datanodes = 0
13
/11/03
18:07:49 INFO namenode.FSNamesystem: dfs.namenode.safemode.extension = 30000
13
/11/03
18:07:49 INFO namenode.FSNamesystem: Retry cache on namenode is enabled
13
/11/03
18:07:49 INFO namenode.FSNamesystem: Retry cache will use 0.03 of total heap and retry cache entry expiry
time
is 600000 millis
13
/11/03
18:07:49 INFO util.GSet: Computing capacity
for
map Namenode Retry Cache
13
/11/03
18:07:49 INFO util.GSet: VM
type
= 64-bit
13
/11/03
18:07:49 INFO util.GSet: 0.029999999329447746% max memory = 888.9 MB
13
/11/03
18:07:49 INFO util.GSet: capacity = 2^15 = 32768 entries
13
/11/03
18:07:49 INFO common.Storage: Storage directory \hadoop\data\dfs\namenode has been successfully formatted.
13
/11/03
18:07:49 INFO namenode.FSImage: Saving image
file
\hadoop\data\dfs\namenode\current\fsimage.ckpt_00000000000000
00000 using no compression
13
/11/03
18:07:49 INFO namenode.FSImage: Image
file
\hadoop\data\dfs\namenode\current\fsimage.ckpt_0000000000000000000 o
f size 200 bytes saved
in
0 seconds.
13
/11/03
18:07:49 INFO namenode.NNStorageRetentionManager: Going to retain 1 images with txid >= 0
13
/11/03
18:07:49 INFO util.ExitUtil: Exiting with status 0
13
/11/03
18:07:49 INFO namenode.NameNode: SHUTDOWN_MSG:
/************************************************************
SHUTDOWN_MSG: Shutting down NameNode at ABHIJITG
/x
.x.x.x
************************************************************/
|
然后在cmd下切换目录到hadoop目录下的sbin目录下，运行start-all 会打开四个cmd窗口，可以打开浏览器输入 http://localhost:8042以及http://localhost:50070查看是否配置成功！