idea中使用maven运行wordcount代码
1.创建maven项目
pom文件:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion> <groupId>hadoop01</groupId>
<artifactId>hadoop01</artifactId>
<version>1.0-SNAPSHOT</version> <dependencies>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-common</artifactId>
<version>2.7.1</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-hdfs</artifactId>
<version>2.7.1</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-client</artifactId>
<version>2.7.1</version> </dependency>
</dependencies> <build>
<plugins>
<plugin>
<artifactId>maven-dependency-plugin</artifactId>
<configuration>
<excludeTransitive>false</excludeTransitive>
<stripVersion>true</stripVersion>
<outputDirectory>./lib</outputDirectory>
</configuration>
</plugin>
</plugins>
</build>
</project>
2.编写wordcound
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<Object, Text, Text, IntWritable> { 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<Text, IntWritable, Text, IntWritable> {
private IntWritable result = new IntWritable(); public void reduce(Text key, Iterable<IntWritable> 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);
}
}
3.在src下面创建NativeIO
创建package:org.apache.hadoop.io.nativeio
创建类:NativeIO
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.io.nativeio; import java.io.File;
import java.io.FileDescriptor;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.lang.reflect.Field;
import java.nio.ByteBuffer;
import java.nio.MappedByteBuffer;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap; import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.CommonConfigurationKeys;
import org.apache.hadoop.io.SecureIOUtils.AlreadyExistsException;
import org.apache.hadoop.util.NativeCodeLoader;
import org.apache.hadoop.util.Shell;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory; import sun.misc.Unsafe; import com.google.common.annotations.VisibleForTesting; /**
* JNI wrappers for various native IO-related calls not available in Java.
* These functions should generally be used alongside a fallback to another
* more portable mechanism.
*/
@InterfaceAudience.Private
@InterfaceStability.Unstable
public class NativeIO {
public static class POSIX {
// Flags for open() call from bits/fcntl.h
public static final int O_RDONLY = 00;
public static final int O_WRONLY = 01;
public static final int O_RDWR = 02;
public static final int O_CREAT = 0100;
public static final int O_EXCL = 0200;
public static final int O_NOCTTY = 0400;
public static final int O_TRUNC = 01000;
public static final int O_APPEND = 02000;
public static final int O_NONBLOCK = 04000;
public static final int O_SYNC = 010000;
public static final int O_ASYNC = 020000;
public static final int O_FSYNC = O_SYNC;
public static final int O_NDELAY = O_NONBLOCK; // Flags for posix_fadvise() from bits/fcntl.h
/* No further special treatment. */
public static final int POSIX_FADV_NORMAL = 0;
/* Expect random page references. */
public static final int POSIX_FADV_RANDOM = 1;
/* Expect sequential page references. */
public static final int POSIX_FADV_SEQUENTIAL = 2;
/* Will need these pages. */
public static final int POSIX_FADV_WILLNEED = 3;
/* Don't need these pages. */
public static final int POSIX_FADV_DONTNEED = 4;
/* Data will be accessed once. */
public static final int POSIX_FADV_NOREUSE = 5; /* Wait upon writeout of all pages
in the range before performing the
write. */
public static final int SYNC_FILE_RANGE_WAIT_BEFORE = 1;
/* Initiate writeout of all those
dirty pages in the range which are
not presently under writeback. */
public static final int SYNC_FILE_RANGE_WRITE = 2; /* Wait upon writeout of all pages in
the range after performing the
write. */
public static final int SYNC_FILE_RANGE_WAIT_AFTER = 4; private static final Log LOG = LogFactory.getLog(NativeIO.class); private static boolean nativeLoaded = false;
private static boolean fadvisePossible = true;
private static boolean syncFileRangePossible = true; static final String WORKAROUND_NON_THREADSAFE_CALLS_KEY =
"hadoop.workaround.non.threadsafe.getpwuid";
static final boolean WORKAROUND_NON_THREADSAFE_CALLS_DEFAULT = true; private static long cacheTimeout = -1; private static CacheManipulator cacheManipulator = new CacheManipulator(); public static CacheManipulator getCacheManipulator() {
return cacheManipulator;
} public static void setCacheManipulator(CacheManipulator cacheManipulator) {
POSIX.cacheManipulator = cacheManipulator;
} /**
* Used to manipulate the operating system cache.
*/
@VisibleForTesting
public static class CacheManipulator {
public void mlock(String identifier, ByteBuffer buffer,
long len) throws IOException {
POSIX.mlock(buffer, len);
} public long getMemlockLimit() {
return NativeIO.getMemlockLimit();
} public long getOperatingSystemPageSize() {
return NativeIO.getOperatingSystemPageSize();
} public void posixFadviseIfPossible(String identifier,
FileDescriptor fd, long offset, long len, int flags)
throws NativeIOException {
POSIX.posixFadviseIfPossible(identifier, fd, offset,
len, flags);
} public boolean verifyCanMlock() {
return NativeIO.isAvailable();
}
} /**
* A CacheManipulator used for testing which does not actually call mlock.
* This allows many tests to be run even when the operating system does not
* allow mlock, or only allows limited mlocking.
*/
@VisibleForTesting
public static class NoMlockCacheManipulator extends CacheManipulator {
public void mlock(String identifier, ByteBuffer buffer,
long len) throws IOException {
LOG.info("mlocking " + identifier);
} public long getMemlockLimit() {
return 1125899906842624L;
} public long getOperatingSystemPageSize() {
return 4096;
} public boolean verifyCanMlock() {
return true;
}
} static {
if (NativeCodeLoader.isNativeCodeLoaded()) {
try {
Configuration conf = new Configuration();
workaroundNonThreadSafePasswdCalls = conf.getBoolean(
WORKAROUND_NON_THREADSAFE_CALLS_KEY,
WORKAROUND_NON_THREADSAFE_CALLS_DEFAULT); initNative();
nativeLoaded = true; cacheTimeout = conf.getLong(
CommonConfigurationKeys.HADOOP_SECURITY_UID_NAME_CACHE_TIMEOUT_KEY,
CommonConfigurationKeys.HADOOP_SECURITY_UID_NAME_CACHE_TIMEOUT_DEFAULT) *
1000;
LOG.debug("Initialized cache for IDs to User/Group mapping with a " +
" cache timeout of " + cacheTimeout/1000 + " seconds."); } catch (Throwable t) {
// This can happen if the user has an older version of libhadoop.so
// installed - in this case we can continue without native IO
// after warning
LOG.error("Unable to initialize NativeIO libraries", t);
}
}
} /**
* Return true if the JNI-based native IO extensions are available.
*/
public static boolean isAvailable() {
return NativeCodeLoader.isNativeCodeLoaded() && nativeLoaded;
} private static void assertCodeLoaded() throws IOException {
if (!isAvailable()) {
throw new IOException("NativeIO was not loaded");
}
} /** Wrapper around open(2) */
public static native FileDescriptor open(String path, int flags, int mode) throws IOException;
/** Wrapper around fstat(2) */
private static native Stat fstat(FileDescriptor fd) throws IOException; /** Native chmod implementation. On UNIX, it is a wrapper around chmod(2) */
private static native void chmodImpl(String path, int mode) throws IOException; public static void chmod(String path, int mode) throws IOException {
if (!Shell.WINDOWS) {
chmodImpl(path, mode);
} else {
try {
chmodImpl(path, mode);
} catch (NativeIOException nioe) {
if (nioe.getErrorCode() == 3) {
throw new NativeIOException("No such file or directory",
Errno.ENOENT);
} else {
LOG.warn(String.format("NativeIO.chmod error (%d): %s",
nioe.getErrorCode(), nioe.getMessage()));
throw new NativeIOException("Unknown error", Errno.UNKNOWN);
}
}
}
} /** Wrapper around posix_fadvise(2) */
static native void posix_fadvise(
FileDescriptor fd, long offset, long len, int flags) throws NativeIOException; /** Wrapper around sync_file_range(2) */
static native void sync_file_range(
FileDescriptor fd, long offset, long nbytes, int flags) throws NativeIOException; /**
* Call posix_fadvise on the given file descriptor. See the manpage
* for this syscall for more information. On systems where this
* call is not available, does nothing.
*
* @throws NativeIOException if there is an error with the syscall
*/
static void posixFadviseIfPossible(String identifier,
FileDescriptor fd, long offset, long len, int flags)
throws NativeIOException {
if (nativeLoaded && fadvisePossible) {
try {
posix_fadvise(fd, offset, len, flags);
} catch (UnsupportedOperationException uoe) {
fadvisePossible = false;
} catch (UnsatisfiedLinkError ule) {
fadvisePossible = false;
}
}
} /**
* Call sync_file_range on the given file descriptor. See the manpage
* for this syscall for more information. On systems where this
* call is not available, does nothing.
*
* @throws NativeIOException if there is an error with the syscall
*/
public static void syncFileRangeIfPossible(
FileDescriptor fd, long offset, long nbytes, int flags)
throws NativeIOException {
if (nativeLoaded && syncFileRangePossible) {
try {
sync_file_range(fd, offset, nbytes, flags);
} catch (UnsupportedOperationException uoe) {
syncFileRangePossible = false;
} catch (UnsatisfiedLinkError ule) {
syncFileRangePossible = false;
}
}
} static native void mlock_native(
ByteBuffer buffer, long len) throws NativeIOException;
static native void munlock_native(
ByteBuffer buffer, long len) throws NativeIOException; /**
* Locks the provided direct ByteBuffer into memory, preventing it from
* swapping out. After a buffer is locked, future accesses will not incur
* a page fault.
*
* See the mlock(2) man page for more information.
*
* @throws NativeIOException
*/
static void mlock(ByteBuffer buffer, long len)
throws IOException {
assertCodeLoaded();
if (!buffer.isDirect()) {
throw new IOException("Cannot mlock a non-direct ByteBuffer");
}
mlock_native(buffer, len);
} /**
* Unlocks a locked direct ByteBuffer, allowing it to swap out of memory.
* This is a no-op if the ByteBuffer was not previously locked.
*
* See the munlock(2) man page for more information.
*
* @throws NativeIOException
*/
public static void munlock(ByteBuffer buffer, long len)
throws IOException {
assertCodeLoaded();
if (!buffer.isDirect()) {
throw new IOException("Cannot munlock a non-direct ByteBuffer");
}
munlock_native(buffer, len);
} /**
* Unmaps the block from memory. See munmap(2).
*
* There isn't any portable way to unmap a memory region in Java.
* So we use the sun.nio method here.
* Note that unmapping a memory region could cause crashes if code
* continues to reference the unmapped code. However, if we don't
* manually unmap the memory, we are dependent on the finalizer to
* do it, and we have no idea when the finalizer will run.
*
* @param buffer The buffer to unmap.
*/
public static void munmap(MappedByteBuffer buffer) {
if (buffer instanceof sun.nio.ch.DirectBuffer) {
sun.misc.Cleaner cleaner =
((sun.nio.ch.DirectBuffer)buffer).cleaner();
cleaner.clean();
}
} /** Linux only methods used for getOwner() implementation */
private static native long getUIDforFDOwnerforOwner(FileDescriptor fd) throws IOException;
private static native String getUserName(long uid) throws IOException; /**
* Result type of the fstat call
*/
public static class Stat {
private int ownerId, groupId;
private String owner, group;
private int mode; // Mode constants
public static final int S_IFMT = 0170000; /* type of file */
public static final int S_IFIFO = 0010000; /* named pipe (fifo) */
public static final int S_IFCHR = 0020000; /* character special */
public static final int S_IFDIR = 0040000; /* directory */
public static final int S_IFBLK = 0060000; /* block special */
public static final int S_IFREG = 0100000; /* regular */
public static final int S_IFLNK = 0120000; /* symbolic link */
public static final int S_IFSOCK = 0140000; /* socket */
public static final int S_IFWHT = 0160000; /* whiteout */
public static final int S_ISUID = 0004000; /* set user id on execution */
public static final int S_ISGID = 0002000; /* set group id on execution */
public static final int S_ISVTX = 0001000; /* save swapped text even after use */
public static final int S_IRUSR = 0000400; /* read permission, owner */
public static final int S_IWUSR = 0000200; /* write permission, owner */
public static final int S_IXUSR = 0000100; /* execute/search permission, owner */ Stat(int ownerId, int groupId, int mode) {
this.ownerId = ownerId;
this.groupId = groupId;
this.mode = mode;
} Stat(String owner, String group, int mode) {
if (!Shell.WINDOWS) {
this.owner = owner;
} else {
this.owner = stripDomain(owner);
}
if (!Shell.WINDOWS) {
this.group = group;
} else {
this.group = stripDomain(group);
}
this.mode = mode;
} @Override
public String toString() {
return "Stat(owner='" + owner + "', group='" + group + "'" +
", mode=" + mode + ")";
} public String getOwner() {
return owner;
}
public String getGroup() {
return group;
}
public int getMode() {
return mode;
}
} /**
* Returns the file stat for a file descriptor.
*
* @param fd file descriptor.
* @return the file descriptor file stat.
* @throws IOException thrown if there was an IO error while obtaining the file stat.
*/
public static Stat getFstat(FileDescriptor fd) throws IOException {
Stat stat = null;
if (!Shell.WINDOWS) {
stat = fstat(fd);
stat.owner = getName(IdCache.USER, stat.ownerId);
stat.group = getName(IdCache.GROUP, stat.groupId);
} else {
try {
stat = fstat(fd);
} catch (NativeIOException nioe) {
if (nioe.getErrorCode() == 6) {
throw new NativeIOException("The handle is invalid.",
Errno.EBADF);
} else {
LOG.warn(String.format("NativeIO.getFstat error (%d): %s",
nioe.getErrorCode(), nioe.getMessage()));
throw new NativeIOException("Unknown error", Errno.UNKNOWN);
}
}
}
return stat;
} private static String getName(IdCache domain, int id) throws IOException {
Map<Integer, CachedName> idNameCache = (domain == IdCache.USER)
? USER_ID_NAME_CACHE : GROUP_ID_NAME_CACHE;
String name;
CachedName cachedName = idNameCache.get(id);
long now = System.currentTimeMillis();
if (cachedName != null && (cachedName.timestamp + cacheTimeout) > now) {
name = cachedName.name;
} else {
name = (domain == IdCache.USER) ? getUserName(id) : getGroupName(id);
if (LOG.isDebugEnabled()) {
String type = (domain == IdCache.USER) ? "UserName" : "GroupName";
LOG.debug("Got " + type + " " + name + " for ID " + id +
" from the native implementation");
}
cachedName = new CachedName(name, now);
idNameCache.put(id, cachedName);
}
return name;
} static native String getUserName(int uid) throws IOException;
static native String getGroupName(int uid) throws IOException; private static class CachedName {
final long timestamp;
final String name; public CachedName(String name, long timestamp) {
this.name = name;
this.timestamp = timestamp;
}
} private static final Map<Integer, CachedName> USER_ID_NAME_CACHE =
new ConcurrentHashMap<Integer, CachedName>(); private static final Map<Integer, CachedName> GROUP_ID_NAME_CACHE =
new ConcurrentHashMap<Integer, CachedName>(); private enum IdCache { USER, GROUP } public final static int MMAP_PROT_READ = 0x1;
public final static int MMAP_PROT_WRITE = 0x2;
public final static int MMAP_PROT_EXEC = 0x4; public static native long mmap(FileDescriptor fd, int prot,
boolean shared, long length) throws IOException; public static native void munmap(long addr, long length)
throws IOException;
} private static boolean workaroundNonThreadSafePasswdCalls = false; public static class Windows {
// Flags for CreateFile() call on Windows
public static final long GENERIC_READ = 0x80000000L;
public static final long GENERIC_WRITE = 0x40000000L; public static final long FILE_SHARE_READ = 0x00000001L;
public static final long FILE_SHARE_WRITE = 0x00000002L;
public static final long FILE_SHARE_DELETE = 0x00000004L; public static final long CREATE_NEW = 1;
public static final long CREATE_ALWAYS = 2;
public static final long OPEN_EXISTING = 3;
public static final long OPEN_ALWAYS = 4;
public static final long TRUNCATE_EXISTING = 5; public static final long FILE_BEGIN = 0;
public static final long FILE_CURRENT = 1;
public static final long FILE_END = 2; /** Wrapper around CreateFile() on Windows */
public static native FileDescriptor createFile(String path,
long desiredAccess, long shareMode, long creationDisposition)
throws IOException; /** Wrapper around SetFilePointer() on Windows */
public static native long setFilePointer(FileDescriptor fd,
long distanceToMove, long moveMethod) throws IOException; /** Windows only methods used for getOwner() implementation */
private static native String getOwner(FileDescriptor fd) throws IOException; /** Supported list of Windows access right flags */
public static enum AccessRight {
ACCESS_READ (0x0001), // FILE_READ_DATA
ACCESS_WRITE (0x0002), // FILE_WRITE_DATA
ACCESS_EXECUTE (0x0020); // FILE_EXECUTE private final int accessRight;
AccessRight(int access) {
accessRight = access;
} public int accessRight() {
return accessRight;
}
}; /** Windows only method used to check if the current process has requested
* access rights on the given path. */
private static native boolean access0(String path, int requestedAccess); /**
* Checks whether the current process has desired access rights on
* the given path.
*
* Longer term this native function can be substituted with JDK7
* function Files#isReadable, isWritable, isExecutable.
*
* @param path input path
* @param desiredAccess ACCESS_READ, ACCESS_WRITE or ACCESS_EXECUTE
* @return true if access is allowed
* @throws IOException I/O exception on error
*/
public static boolean access(String path, AccessRight desiredAccess)
throws IOException {
return true;
//return access0(path, desiredAccess.accessRight());
} static {
if (NativeCodeLoader.isNativeCodeLoaded()) {
try {
initNative();
nativeLoaded = true;
} catch (Throwable t) {
// This can happen if the user has an older version of libhadoop.so
// installed - in this case we can continue without native IO
// after warning
LOG.error("Unable to initialize NativeIO libraries", t);
}
}
}
} private static final Log LOG = LogFactory.getLog(NativeIO.class); private static boolean nativeLoaded = false; static {
if (NativeCodeLoader.isNativeCodeLoaded()) {
try {
initNative();
nativeLoaded = true;
} catch (Throwable t) {
// This can happen if the user has an older version of libhadoop.so
// installed - in this case we can continue without native IO
// after warning
LOG.error("Unable to initialize NativeIO libraries", t);
}
}
} /**
* Return true if the JNI-based native IO extensions are available.
*/
public static boolean isAvailable() {
return NativeCodeLoader.isNativeCodeLoaded() && nativeLoaded;
} /** Initialize the JNI method ID and class ID cache */
private static native void initNative(); /**
* Get the maximum number of bytes that can be locked into memory at any
* given point.
*
* @return 0 if no bytes can be locked into memory;
* Long.MAX_VALUE if there is no limit;
* The number of bytes that can be locked into memory otherwise.
*/
static long getMemlockLimit() {
return isAvailable() ? getMemlockLimit0() : 0;
} private static native long getMemlockLimit0(); /**
* @return the operating system's page size.
*/
static long getOperatingSystemPageSize() {
try {
Field f = Unsafe.class.getDeclaredField("theUnsafe");
f.setAccessible(true);
Unsafe unsafe = (Unsafe)f.get(null);
return unsafe.pageSize();
} catch (Throwable e) {
LOG.warn("Unable to get operating system page size. Guessing 4096.", e);
return 4096;
}
} private static class CachedUid {
final long timestamp;
final String username;
public CachedUid(String username, long timestamp) {
this.timestamp = timestamp;
this.username = username;
}
}
private static final Map<Long, CachedUid> uidCache =
new ConcurrentHashMap<Long, CachedUid>();
private static long cacheTimeout;
private static boolean initialized = false; /**
* The Windows logon name has two part, NetBIOS domain name and
* user account name, of the format DOMAIN\UserName. This method
* will remove the domain part of the full logon name.
*
* @param the full principal name containing the domain
* @return name with domain removed
*/
private static String stripDomain(String name) {
int i = name.indexOf('\\');
if (i != -1)
name = name.substring(i + 1);
return name;
} public static String getOwner(FileDescriptor fd) throws IOException {
ensureInitialized();
if (Shell.WINDOWS) {
String owner = Windows.getOwner(fd);
owner = stripDomain(owner);
return owner;
} else {
long uid = POSIX.getUIDforFDOwnerforOwner(fd);
CachedUid cUid = uidCache.get(uid);
long now = System.currentTimeMillis();
if (cUid != null && (cUid.timestamp + cacheTimeout) > now) {
return cUid.username;
}
String user = POSIX.getUserName(uid);
LOG.info("Got UserName " + user + " for UID " + uid
+ " from the native implementation");
cUid = new CachedUid(user, now);
uidCache.put(uid, cUid);
return user;
}
} /**
* Create a FileInputStream that shares delete permission on the
* file opened, i.e. other process can delete the file the
* FileInputStream is reading. Only Windows implementation uses
* the native interface.
*/
public static FileInputStream getShareDeleteFileInputStream(File f)
throws IOException {
if (!Shell.WINDOWS) {
// On Linux the default FileInputStream shares delete permission
// on the file opened.
//
return new FileInputStream(f);
} else {
// Use Windows native interface to create a FileInputStream that
// shares delete permission on the file opened.
//
FileDescriptor fd = Windows.createFile(
f.getAbsolutePath(),
Windows.GENERIC_READ,
Windows.FILE_SHARE_READ |
Windows.FILE_SHARE_WRITE |
Windows.FILE_SHARE_DELETE,
Windows.OPEN_EXISTING);
return new FileInputStream(fd);
}
} /**
* Create a FileInputStream that shares delete permission on the
* file opened at a given offset, i.e. other process can delete
* the file the FileInputStream is reading. Only Windows implementation
* uses the native interface.
*/
public static FileInputStream getShareDeleteFileInputStream(File f, long seekOffset)
throws IOException {
if (!Shell.WINDOWS) {
RandomAccessFile rf = new RandomAccessFile(f, "r");
if (seekOffset > 0) {
rf.seek(seekOffset);
}
return new FileInputStream(rf.getFD());
} else {
// Use Windows native interface to create a FileInputStream that
// shares delete permission on the file opened, and set it to the
// given offset.
//
FileDescriptor fd = Windows.createFile(
f.getAbsolutePath(),
Windows.GENERIC_READ,
Windows.FILE_SHARE_READ |
Windows.FILE_SHARE_WRITE |
Windows.FILE_SHARE_DELETE,
Windows.OPEN_EXISTING);
if (seekOffset > 0)
Windows.setFilePointer(fd, seekOffset, Windows.FILE_BEGIN);
return new FileInputStream(fd);
}
} /**
* Create the specified File for write access, ensuring that it does not exist.
* @param f the file that we want to create
* @param permissions we want to have on the file (if security is enabled)
*
* @throws AlreadyExistsException if the file already exists
* @throws IOException if any other error occurred
*/
public static FileOutputStream getCreateForWriteFileOutputStream(File f, int permissions)
throws IOException {
if (!Shell.WINDOWS) {
// Use the native wrapper around open(2)
try {
FileDescriptor fd = POSIX.open(f.getAbsolutePath(),
POSIX.O_WRONLY | POSIX.O_CREAT
| POSIX.O_EXCL, permissions);
return new FileOutputStream(fd);
} catch (NativeIOException nioe) {
if (nioe.getErrno() == Errno.EEXIST) {
throw new AlreadyExistsException(nioe);
}
throw nioe;
}
} else {
// Use the Windows native APIs to create equivalent FileOutputStream
try {
FileDescriptor fd = Windows.createFile(f.getCanonicalPath(),
Windows.GENERIC_WRITE,
Windows.FILE_SHARE_DELETE
| Windows.FILE_SHARE_READ
| Windows.FILE_SHARE_WRITE,
Windows.CREATE_NEW);
POSIX.chmod(f.getCanonicalPath(), permissions);
return new FileOutputStream(fd);
} catch (NativeIOException nioe) {
if (nioe.getErrorCode() == 80) {
// ERROR_FILE_EXISTS
// 80 (0x50)
// The file exists
throw new AlreadyExistsException(nioe);
}
throw nioe;
}
}
} private synchronized static void ensureInitialized() {
if (!initialized) {
cacheTimeout =
new Configuration().getLong("hadoop.security.uid.cache.secs",
4*60*60) * 1000;
LOG.info("Initialized cache for UID to User mapping with a cache" +
" timeout of " + cacheTimeout/1000 + " seconds.");
initialized = true;
}
} /**
* A version of renameTo that throws a descriptive exception when it fails.
*
* @param src The source path
* @param dst The destination path
*
* @throws NativeIOException On failure.
*/
public static void renameTo(File src, File dst)
throws IOException {
if (!nativeLoaded) {
if (!src.renameTo(dst)) {
throw new IOException("renameTo(src=" + src + ", dst=" +
dst + ") failed.");
}
} else {
renameTo0(src.getAbsolutePath(), dst.getAbsolutePath());
}
} /**
* A version of renameTo that throws a descriptive exception when it fails.
*
* @param src The source path
* @param dst The destination path
*
* @throws NativeIOException On failure.
*/
private static native void renameTo0(String src, String dst)
throws NativeIOException;
}
4.确保hadoop运行正常,将文件上传到hdfs上
hadoop fs -mkdir -p /user/root/input
随便创建一个文件,比如:/root/a.txt,在里面输入点内容。wordcount是按照行进行分割统计的。
hadoop fs -put /root/a.txt /user/root/input
5.配置application
在idea右上角点击红框标记的地方,在之后的页面中的加号中添加一个applicaiton,将下图的三个地方配置好,第二个是代码指定的输入路径和输出路径
6.运行如果没有报错就表示成功。
可以在浏览器访问 http://192.168.21.101:50070/explorer.html#/ 查看hdfs上的数据(ip换成自己的)
2017-07-24 23:52:25
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