hdfs user 连接_通过API访问HDFS
通過API操作HDFS
今天的主要內容
HDFS獲取文件系統
HDFS文件上傳
HDFS文件下載
HDFS目錄創建
HDFS文件夾刪除
HDFS文件名更改
HDFS文件詳情查看
定位文件讀取
FileSystem類的學習
1. HDFS獲取文件系統
//獲取文件系統
@Test
public void initHDFS() throws Exception{
//1. 獲取文件系統
Configuration configuration = new Configuration();
FileSystem fileSystem = FileSystem.get(configuration);
//2. 打印文件系統到控制臺
System.out.println(fileSystem.toString());
}
2. HDFS文件上傳(測試參數優先級)
@Test
public void putFileToHdfs() throws Exception{
Configuration conf = new Configuration();
conf.set("dfs.replication", "2"); //代碼優先級是最高的
conf.set("fs.defaultFS", "hdfs://10.9.190.111:9000");
FileSystem fileSystem = FileSystem.get(conf);
//上傳文件
fileSystem.copyFromLocalFile(new Path("hdfs.txt"), new Path("/user/anna/hdfs/test.txt"));
//關閉資源
fileSystem.close();
}
參數優先級：(1)客戶端代碼中設置的值 >(2)classpath 下的用戶自定義配置文件 > (3)然后是服務器的默認配置
3. HDFS文件下載
public void copyToLocalFile(boolean delSrc,Path src,Path dst,boolean useRawLocalFileSystem)
throws IOException
delSrc - whether to delete the src
src - path
dst - path
useRawLocalFileSystem - whether to use RawLocalFileSystem as local file system or not.
@Test
public void testCopyToLocalFile() throws Exception{
Configuration conf = new Configuration();
conf.set("fs.defaultFS", "hdfs://10.9.190.111:9000");
FileSystem fileSystem = FileSystem.get(conf);
///下載文件
fileSystem.copyToLocalFile(false,new Path("/user/anna/hdfs/test.txt"), new Path("test.txt"),true);
//關閉資源
fileSystem.close();
}
4. HDFS目錄創建
@Test
public void testMakedir() throws Exception{
Configuration conf = new Configuration();
conf.set("fs.defaultFS", "hdfs://10.9.190.111:9000");
FileSystem fileSystem = FileSystem.get(conf);
//目錄創建
fileSystem.mkdirs(new Path("/user/anna/test/hahaha"));
//關閉資源
fileSystem.close();
}
5. HDFS文件夾刪除
@Test
public void testDelete() throws Exception{
Configuration conf = new Configuration();
conf.set("fs.defaultFS", "hdfs://10.9.190.111:9000");
FileSystem fileSystem = FileSystem.get(conf);
//文件夾刪除
fileSystem.delete(new Path("/user/anna/test/hahaha"),true); //true表示遞歸刪除
//關閉資源
fileSystem.close();
}
6. HDFS文件名更改
@Test
public void testRename() throws Exception{
Configuration conf = new Configuration();
conf.set("fs.defaultFS", "hdfs://10.9.190.111:9000");
FileSystem fileSystem = FileSystem.get(conf);
//文件名稱更改
fileSystem.rename(new Path("/user/anna/test/copy.txt"), new Path("/user/anna/test/copyRename.txt"));
//關閉資源
fileSystem.close();
}
7. HDFS文件詳情查看
幾種實現方法
1. public abstract FileStatus[] listStatus(Path f) throws FileNotFoundException,IOException
* 返回FileStatus型數組
2. public FileStatus[] listStatus(Path f,PathFilter filter) throws FileNotFoundException,IOException
3. public FileStatus[] listStatus(Path[] files,PathFilter filter) throws FileNotFoundException,IOException
* 此時注意PathFilter是一個接口，里面只有一個方法:accept，本質是對文件進行篩選
* Enumerate all files found in the list of directories passed in, calling listStatus(path, filter) on each one.
注意：以上方法返回的文件按照字母表順序排列
代碼：FileStatus[] listStatus(Path f)
//FileStatus[] listStatus(Path f)的使用
try {
//創建與HDFS連接
Configuration conf = new Configuration();
conf.set("fs.defaultFS","hdfs://10.9.190.90:9000");
//獲得fileSystem
FileSystem fileSystem = FileSystem.get(conf);
//listStatus獲取/test目錄下信息
FileStatus[] fileStatuses = fileSystem.listStatus(new Path("/test"));
//遍歷輸出文件夾下文件
for(FileStatus fileStatus :fileStatuses) {
System.out.println(fileStatus.getPath() + " " + new Date(fileStatus.getAccessTime()) + " " +
fileStatus.getBlockSize() + " " + fileStatus.getPermission());
}
}catch(Exception e) {
e.printStackTrace();
}
/*
在JDK1.8中輸出結果為：
----------------------------------------------------------------------------
hdfs://10.9.190.90:9000/test/hadoop-2.7.3.tar.gz 2012-07-26 134217728 rw-r--r--
hdfs://10.9.190.90:9000/test/hello.txt 2012-07-26 134217728 rw-r--r--
hdfs://10.9.190.90:9000/test/test2 1970-01-01 0 rwxr-xr-x
----------------------------------------------------------------------------
*/
代碼：FileStatus[] listStatus(Path f,PathFilter filter)
try {
//創建與HDFS連接
Configuration conf = new Configuration();
conf.set("fs.defaultFS","hdfs://10.9.190.90:9000");
//獲得fileSystem
FileSystem fileSystem = FileSystem.get(conf);
//列出目錄下后綴為.md的文件相關信息
FileStatus[] statuses = fileSystem.listStatus(new Path("/test/test2"), new PathFilter() {
@Override
public boolean accept(Path path) {
// TODO Auto-generated method stub
String string = path.toString();
if(string.endsWith(".md"))
return true;
else
return false;
}
});
//列出文件信息
for(FileStatus status : statuses) {
System.out.println("Path : " + status.getPath() + " Permisson : " + status.getPermission() +
" Replication : " + status.getReplication());
}
}catch(Exception e) {
e.printStackTrace();
}
7. 定位文件讀取
8. FileSystem類的學習
FileSystem的學習
今天的主要內容
對照官方文檔進行FileSystem類的學習
FileSystem中的方法
* boolean exists(Path p)
* boolean isDirectory(Path p)
* boolean isFile(Path p)
* FileStatus getFileStatus(Path p)
* Path getHomeDirectory()
* FileStatus[] listStatus(Path path, PathFilter filter)
FileStatus[] listStatus(Path path)
FileStatus[] listStatus(Path[] paths, PathFilter filter)
FileStatus[] listStatus(Path[] paths)
* RemoteIterator[LocatedFileStatus] listLocatedStatus(Path path, PathFilter filter)
RemoteIterator[LocatedFileStatus] listLocatedStatus(Path path)
RemoteIterator[LocatedFileStatus] listFiles(Path path, boolean recursive)
* BlockLocation[] getFileBlockLocations(FileStatus f, int s, int l)
BlockLocation[] getFileBlockLocations(Path P, int S, int L)
* long getDefaultBlockSize()
long getDefaultBlockSize(Path p)
long getBlockSize(Path p)
* boolean mkdirs(Path p, FsPermission permission)
* FSDataOutputStream create(Path, ...)
FSDataOutputStream append(Path p, int bufferSize, Progressable progress)
FSDataInputStream open(Path f, int bufferSize)
* boolean delete(Path p, boolean recursive)
* boolean rename(Path src, Path d)
* void concat(Path p, Path sources[])
* boolean truncate(Path p, long newLength)
* interface RemoteIterator
boolean hasNext()
E next()
* interface StreamCapabilities
boolean hasCapability(capability)
準備工作
start-dfs.sh啟動hadoop集群
eclipse進行hdfs文件系統的訪問
導入相應的jar包
創建與hdfs的連接并獲取FileSystem文件對象
第一種方式
* public static FileSystem get(Configuration conf) throws IOException
//創建與HDFS連接
Configuration conf = new Configuration();
conf.set("fs.defaultFS","hdfs://10.9.190.90:9000"); //namenode上的IP地址 端口為：9000
//獲得fileSystem
FileSystem fileSystem = FileSystem.get(conf);
第二種方式
* public static FileSystem get(URI uri,Configuration conf,String user)
throws IOException,
InterruptedException
URL.setURLStreamHandlerFactory(new FsUrlStreamHandlerFactory());
FileSystem fileSystem = FileSystem.get(new URI("hdfs://10.9.190.90:9000"),new Configuration(),"root");
//此時工作目錄會相應更改為/user/root
兩種方式比較
第二種方式可能會拋出InterruptedException異常，因為
the static FileSystem get(URI uri, Configuration conf,String user) method MAY return a pre-existing instance of a filesystem client class—a class that may also be in use in other threads. The implementations of FileSystem shipped with Apache Hadoop do not make any attempt to synchronize access to the working directory field.(此時get方法可能會返回一個已經存在FileSystem對象，也就是存在線程異步問題，所以我們盡量用前一種方式來完成FileSystem對象的創建)
org.apache.hadoop.fs.FileSystem簡介
The abstract FileSystem class is the original class to access Hadoop filesystems; non-abstract subclasses exist for all Hadoop-supported filesystems.(抽象基類FileSystem定義了對hadoop文件系統的操作)
All operations that take a Path to this interface MUST support relative paths. In such a case, they must be resolved relative to the working directory defined by setWorkingDirectory().(setWorkingDirectory()方法默認工作目錄)
FileSystem中的getWorkingDirector()返回當前系統的工作目錄
代碼
//獲得與hdfs文件系統的連接
Configuration conf = new Configuration();
conf.set("fs.defaultFS", "hdfs://10.9.190.90:9000");
//獲取文件系統對象
FileSystem fileSystem = FileSystem.get(conf);
//獲取當前工作目錄
System.out.println("=========獲取當前工作目錄=============");
System.out.println(fileSystem.getWorkingDirectory());
//設置新的工作目錄
//System.out.println("=========設置新的工作目錄=============");
fileSystem.setWorkingDirectory(new Path("hdfs://10.9.190.90:9000/user/anna")); //Path在hdfs中的作用和File作用類似，代表路徑
結果
=========獲取當前工作目錄=============
hdfs://10.9.190.90:9000/user/root
=========獲取設置后工作目錄=============
hdfs://10.9.190.90:9000/user/anna
FileSystem方法——判斷功能
預備知識
import org.apache.hadoop.fs.Path;類似于java.io.File代表hdfs的文件路徑
方法
public boolean exists(Path f) throws IOException
判斷文件是否存在
public boolean isDirectory(Path f) throws IOException
判斷是否為目錄
public boolean isFile(Path f) throws IOException
判斷是否為文件
練習
try {
//獲得與hdfs文件系統的連接
Configuration conf = new Configuration();
conf.set("fs.defaultFS", "hdfs://10.9.190.90:9000");
//獲取連接對象
FileSystem fileSystem = FileSystem.get(conf);
//判斷文件是否存在
System.out.println(fileSystem.exists(new Path("/test"))); //true
//判斷是否為目錄
System.out.println(fileSystem.isDirectory(new Path("/test"))); //true
//判斷是否為文件
System.out.println(fileSystem.isFile(new Path("/test"))); //false
}catch(Exception e) {
e.printStackTrace();
}
FileSystem方法——獲取功能—文件信息獲取
方法
public abstract FileStatus getFileStatus(Path f) throws IOException
Return a file status object that represents the path.
返回的是FileStatus對象類型
public Path getHomeDirectory()
Return the current user's home directory in this FileSystem. The default implementation returns "/user/$USER/".
返回當前用戶的home目錄
練習
try {
//獲得與hdfs文件系統的連接
Configuration conf = new Configuration();
conf.set("fs.defaultFS", "hdfs://10.9.190.90:9000");
//獲取連接對象
FileSystem fileSystem = FileSystem.get(conf);
//獲取當前用戶的home目錄
System.out.println("========當前用戶的home目錄============");
Path path = fileSystem.getHomeDirectory();
System.out.println(path);
//獲取文件狀態對象
System.out.println("============文件信息===============");
FileStatus status = fileSystem.getFileStatus(new Path("/eclipse"));
System.out.println("Path : " + status.getPath());
System.out.println("isFile ? " + status.isFile());
System.out.println("Block size : " + status.getBlockSize());
System.out.println("Perssions : " + status.getPermission());
System.out.println("Replication : " + status.getReplication());
System.out.println("isSymlink : " + status.isSymlink());
}catch(Exception e) {
e.printStackTrace();
}
/*
在JDK1.8中輸出結果為：
* ------------------------------------------------
* ========當前用戶的home目錄============
hdfs://10.9.190.90:9000/user/anna
============文件信息===============
Path : hdfs://10.9.190.90:9000/eclipse
isFile ? true
Block size : 134217728
Perssions : rw-r--r--
Replication : 3
isSymlink : false
------------------------------------------------
*/
FileStatus中常用方法
public Path getPath()
public boolean isFile()
public boolean isSymlink()
public long getBlockSize()
public short getReplication()
public FsPermission getPermission()
FileSystem方法——獲取功能——文件夾遍歷1
方法
public abstract FileStatus[] listStatus(Path f) throws FileNotFoundException,IOException
返回FileStatus型數組
public FileStatus[] listStatus(Path f,PathFilter filter)
throws FileNotFoundException,IOException
public FileStatus[] listStatus(Path[] files,PathFilter filter)
throws FileNotFoundException,IOException
此時注意PathFilter是一個接口，里面只有一個方法:accept，本質是對文件進行篩選
Enumerate all files found in the list of directories passed in, calling listStatus(path, filter) on each one.
注意：以上方法返回的文件按照字母表順序排列
練習1——FileStatus[] listStatus(Path f)的使用
//FileStatus[] listStatus(Path f)的使用
try {
//創建與HDFS連接
Configuration conf = new Configuration();
conf.set("fs.defaultFS","hdfs://10.9.190.90:9000");
//獲得fileSystem
FileSystem fileSystem = FileSystem.get(conf);
//listStatus獲取/test目錄下信息
FileStatus[] fileStatuses = fileSystem.listStatus(new Path("/test"));
//遍歷輸出文件夾下文件
for(FileStatus fileStatus :fileStatuses) {
System.out.println(fileStatus.getPath() + " " + new Date(fileStatus.getAccessTime()) + " " +
fileStatus.getBlockSize() + " " + fileStatus.getPermission());
}
}catch(Exception e) {
e.printStackTrace();
}
/*
在JDK1.8中輸出結果為：
----------------------------------------------------------------------------
hdfs://10.9.190.90:9000/test/hadoop-2.7.3.tar.gz 2012-07-26 134217728 rw-r--r--
hdfs://10.9.190.90:9000/test/hello.txt 2012-07-26 134217728 rw-r--r--
hdfs://10.9.190.90:9000/test/test2 1970-01-01 0 rwxr-xr-x
----------------------------------------------------------------------------
*/
練習2——FileStatus[] listStatus(Path f,PathFilter filter)的使用
需求：列出/test/test2目錄下以.md結尾的問價信息
代碼：
try {
//創建與HDFS連接
Configuration conf = new Configuration();
conf.set("fs.defaultFS","hdfs://10.9.190.90:9000");
//獲得fileSystem
FileSystem fileSystem = FileSystem.get(conf);
//列出目錄下后綴為.md的文件相關信息
FileStatus[] statuses = fileSystem.listStatus(new Path("/test/test2"), new PathFilter() {
@Override
public boolean accept(Path path) {
// TODO Auto-generated method stub
String string = path.toString();
if(string.endsWith(".md"))
return true;
else
return false;
}
});
//列出文件信息
for(FileStatus status : statuses) {
System.out.println("Path : " + status.getPath() + " Permisson : " + status.getPermission() +
" Replication : " + status.getReplication());
}
}catch(Exception e) {
e.printStackTrace();
}
注意問題
By the time the listStatus() operation returns to the caller, there is no guarantee that the information contained in the response is current. The details MAY be out of date, including the contents of any directory, the attributes of any files, and the existence of the path supplied.(listStatus()方法線程不安全)
FileSystem方法——獲取功能——文件夾遍歷2
方法
public org.apache.hadoop.fs.RemoteIterator listLocatedStatus(Path f)
throws FileNotFoundException, IOException
protected org.apache.hadoop.fs.RemoteIterator listLocatedStatus(Path f,PathFilter filter)
throws FileNotFoundException, IOException
注意：此方法是protected的，protected權限是：本類，同一包下(子類或無關類)，不同包下子類
注意：LocatedFileStatus是FileStatus的子類
使用
try {
//創建與HDFS連接
Configuration conf = new Configuration();
conf.set("fs.defaultFS","hdfs://10.9.190.90:9000");
//獲得fileSystem
FileSystem fileSystem = FileSystem.get(conf);
//列出目錄下后綴為.md的文件相關信息
RemoteIterator iterator = fileSystem.listLocatedStatus(new Path("/test/test2"));
while(iterator.hasNext()) {
LocatedFileStatus status = iterator.next();
System.out.println("Path : " + status.getPath() + " Permisson : " + status.getPermission() +
" Replication : " + status.getReplication());
}
}catch(Exception e) {
e.printStackTrace();
}
/*
* 在JDK1.8中輸出結果為：
* ---------------------------------------------------------------------------------------------
* Path : hdfs://10.9.190.90:9000/test/test2/Map.md Permisson : rw-r--r-- Replication : 3
Path : hdfs://10.9.190.90:9000/test/test2/biji.md Permisson : rw-r--r-- Replication : 3
Path : hdfs://10.9.190.90:9000/test/test2/haha.txt Permisson : rw-r--r-- Replication : 3
---------------------------------------------------------------------------------------------
* */
與listStatus(Path p)不同的是
listStatus返回的是FileStatus[]數組類型，遍歷時可通過數組for-each進行遍歷
listLocatedStatus(Path p)返回的是LocatedFileStatus類型的RemoteIterator集合，通過迭代器進行遍歷輸出
但是要注意的是listLocatedStatus()方法本質上內部還是listStatus(Path p)實現的
FileSystem方法——獲取功能——文件夾遍歷3
方法
public org.apache.hadoop.fs.RemoteIterator listFiles(Path f,boolean recursive)
throws FileNotFoundException,IOException
遞歸遍歷出文件夾內容以及子文件夾中內容
使用
try {
//創建與HDFS連接
Configuration conf = new Configuration();
conf.set("fs.defaultFS","hdfs://10.9.190.90:9000");
//獲得fileSystem
FileSystem fileSystem = FileSystem.get(conf);
//列出目錄下后綴為.md的文件相關信息
RemoteIterator iterator = fileSystem.listFiles(new Path("/test"),true);
while(iterator.hasNext()) {
LocatedFileStatus status = iterator.next();
System.out.println("Path : " + status.getPath() + " Permisson : " + status.getPermission() +
" Replication : " + status.getReplication());
}
}catch(Exception e) {
e.printStackTrace();
}
/*
* 在JDK1.8中輸出結果為：
* ---------------------------------------------------------------------------------------------------
* Path : hdfs://10.9.190.90:9000/test/hadoop-2.7.3.tar.gz Permisson : rw-r--r-- Replication : 3
Path : hdfs://10.9.190.90:9000/test/hello.txt Permisson : rw-r--r-- Replication : 3
Path : hdfs://10.9.190.90:9000/test/test2/Map.md Permisson : rw-r--r-- Replication : 3
Path : hdfs://10.9.190.90:9000/test/test2/biji.md Permisson : rw-r--r-- Replication : 3
Path : hdfs://10.9.190.90:9000/test/test2/haha.txt Permisson : rw-r--r-- Replication : 3
---------------------------------------------------------------------------------------------------
* */
FileSystem方法——獲取功能——獲取文件block的位置
方法
public BlockLocation[] getFileBlockLocations(Path p,long start,long len) throws IOException
public BlockLocation[] getFileBlockLocations(FileStatus file,long start,long len) throws IOException
使用
//查看/test/hadoop的block存放位置
try {
//創建與HDFS連接
Configuration conf = new Configuration();
conf.set("fs.defaultFS","hdfs://10.9.190.90:9000");
//獲得fileSystem
FileSystem fileSystem = FileSystem.get(conf);
FileStatus status = fileSystem.getFileStatus(new Path("/test/hadoop"));
BlockLocation[] locations = fileSystem.getFileBlockLocations(status, 0,status.getLen());
for(BlockLocation location : locations) {
System.out.println("host : " + location.getHosts() + " name : " + location.getNames() + " length : " + location.getLength());
}
}catch(Exception e) {
e.printStackTrace();
}
/*
在JDK1.8中輸出結果為：
------------------------------------------------------------------------------
host : [Ljava.lang.String;@18ece7f4 name : [Ljava.lang.String;@3cce57c7 length : 134217728
host : [Ljava.lang.String;@1cf56a1c name : [Ljava.lang.String;@33f676f6 length : 79874467
------------------------------------------------------------------------------
*/
FileSystem方法——獲取功能——獲取到某文件的輸出流
方法
public FSDataOutputStream create(Path f) throws IOException
public FSDataOutputStream create(Path f,boolean overwrite)
throws IOException
overwrite - if a file with this name already exists, then if true, the file will be overwritten, and if false an exception will be thrown.
public FSDataOutputStream create(Path f,
Progressable progress)
throws IOException
Create an FSDataOutputStream at the indicated Path with write-progress reporting. Files are overwritten by default.
public FSDataOutputStream create(Path f,boolean overwrite,int bufferSize)
throws IOException
public FSDataOutputStream create(Path f,boolean overwrite,int bufferSize, Progressable progress)throws IOException
FSDataOutputStream append(Path p, int bufferSize, Progressable progress)
使用——將本地E:/hzy.jpg上傳到hdfs的/1.jpg
public static void main(String[] args) {
BufferedInputStream in = null;
FSDataOutputStream out = null;
try {
//創建與HDFS連接
Configuration conf = new Configuration();
conf.set("fs.defaultFS","hdfs://10.9.190.90:9000");
//獲得fileSystem
FileSystem fileSystem = FileSystem.get(conf);
//獲取本地文件輸入流
File file = new File("E:/hzy.jpg");
in = new BufferedInputStream(new FileInputStream(file));
final long fileSize = file.length();
//獲取到/test/hello.txt的輸出流
out = fileSystem.create(new Path("/1.jpg"),new Progressable() {
long fileCount = 0;
@Override
public void progress() {
// TODO Auto-generated method stub
fileCount++;
System.out.println("總進度：" + (fileCount/fileSize)*100 + " %");
}
});
//拷貝
int len = 0;
while((len = in.read()) != -1) {
out.write(len); //此時也可以用:IOUtils.copyBytes(in,out,conf);
}
in.close();
out.close();
}catch(Exception e) {
e.printStackTrace();
}finally {
if(in != null) {
try {
in.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (out != null) {
try {
out.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
FileSystem方法——獲取功能——獲取到某文件的輸入流——讀取文件
方法
public FSDataInputStream open(Path f) throws IOException
public abstract FSDataInputStream open(Path f,int bufferSize)throws IOException
使用——將hdfs中的1.jpg拷貝到本地E:/hzy2.jpg
try {
//創建與HDFS連接
Configuration conf = new Configuration();
conf.set("fs.defaultFS","hdfs://10.9.190.90:9000");
//獲得fileSystem
FileSystem fileSystem = FileSystem.get(conf);
//獲取hdfs文件輸入流
FSDataInputStream in = fileSystem.open(new Path("/1.jpg"));
//獲取本地輸出流
BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(new File("E:/hzyCopy.jpg")));
int len = 0;
byte[] bArr = new byte[1024*3];
while((len = in.read(bArr)) != -1) {
out.write(bArr,0,len);
}
in.close();
out.close();
}catch(Exception e) {
e.printStackTrace();
}
}
FileSystem方法——創建功能
public boolean mkdirs(Path f) throws IOException
FileSystem方法——刪除功能
public abstract boolean delete(Path f,boolean recursive) throws IOException
設計線程同步問題
FileSystem方法——重命名功能
public abstract boolean rename(Path src,Path dst)throws IOException
FileSystem其他方法
public void concat(Path trg,Path[] psrcs)throws IOException
Concat existing files together.
public boolean truncate(Path f,long newLength)throws IOException
interface RemoteIterator
定義
public interface RemoteIterator {
boolean hasNext() throws IOException;
E next() throws IOException;
}
The primary use of RemoteIterator in the filesystem APIs is to list files on (possibly remote) filesystems.
使用
//listLocatedFileStatus(Path f)
public org.apache.hadoop.fs.RemoteIterator listLocatedStatus(Path f)
throws FileNotFoundException,IOException
//listLocatedStatus(Path f,PathFilter filter)
protected org.apache.hadoop.fs.RemoteIterator listLocatedStatus(Path f,PathFilter filter)
throws FileNotFoundException,IOException
//listStatusIterator(Path p)
public org.apache.hadoop.fs.RemoteIterator listStatusIterator(Path p)
throws FileNotFoundException,IOException
//listFiles(Path f,boolean recursive)
public org.apache.hadoop.fs.RemoteIterator listFiles(Path f,boolean recursive)
throws FileNotFoundException,IOException
interface StreamCapabilities
方法
public interface StreamCapabilities {
boolean hasCapability(String capability);
}
使用
hadoop2.7.3中無此方法，在2.9.1中才有
總結
以上是生活随笔為你收集整理的hdfs user 连接_通过API访问HDFS的全部內容，希望文章能夠幫你解決所遇到的問題。
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