hadoop hdfs java api操做

package com.duking.util;

import java.io.IOException;
import java.util.Date;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.BlockLocation;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;

public class HDFSUtil {

	/**
	 * 建立一個文件
	 * path:路徑   txt：文件類容 
	 * */
	public void	CreateFile(String path,String txt) throws IOException
	{
		Configuration conf=new Configuration(); 
		
		FileSystem hdfs=FileSystem.get(conf); 
		
		byte[] buff=txt.getBytes(); 
		
		Path dfs=new Path(path);
		
		FSDataOutputStream outputStream=hdfs.create(dfs); 
		
		outputStream.write(buff,0,buff.length); 
		
		outputStream.close();
		
		hdfs.close();
		
		System.out.println("Runing CreateFile over!!");
	}

      //上傳本地文件
      public static void uploadFile(String src,String dst) throws IOException{
          Configuration conf = new Configuration();
          FileSystem fs = FileSystem.get(conf);
 　　　　　 Path srcPath = new Path(src); //原路徑
          Path dstPath = new Path(dst); //目標路徑
          //調用文件系統的文件複製函數,前面參數是指是否刪除原文件，true爲刪除，默認爲false
          fs.copyFromLocalFile(false,srcPath, dstPath);
          
          //打印文件路徑
          System.out.println("Upload to "+conf.get("fs.default.name"));
          System.out.println("------------list files------------"+"\n");
          FileStatus [] fileStatus = fs.listStatus(dstPath);
          for (FileStatus file : fileStatus) 
          {
              System.out.println(file.getPath());
          }
          fs.close();
      }

 /** * 建立文件夾 * @param path * @throws IOException */ public void CreateDir(String path) throws IOException { Configuration conf = new Configuration(); FileSystem hdfs=FileSystem.get(conf); Path dfs=new Path(path); hdfs.mkdirs(dfs); hdfs.close(); } /** * 從命名文件 * @param oldpath * @param newpath * @throws IOException */ public void RenameFile(String oldpath,String newpath) throws IOException { Configuration conf = new Configuration(); FileSystem hdfs = FileSystem.get(conf); Path frpaht=new Path(oldpath); //舊的文件名 Path topath=new Path(newpath); //新的文件名 boolean isRename=hdfs.rename(frpaht, topath); String result=isRename?"成功":"失敗"; System.out.println("文件重命名結果爲："+result); hdfs.close(); } /** * 刪除文件 或者目錄 * @param path * @throws IOException */ public void DeleteFile(String path) throws IOException { Configuration conf = new Configuration(); FileSystem hdfs = FileSystem.get(conf); hdfs.delete(new Path(path), true); hdfs.close(); } /** * 判斷文件或目錄是否存在 * @param path * @throws IOException */ public void CheckFile(String path) throws IOException { Configuration conf = new Configuration(); FileSystem hdfs = FileSystem.get(conf); Path findf=new Path(path); boolean isExists=hdfs.exists(findf); System.out.println("Exist?"+isExists); hdfs.close(); } /** * 查看HDFS文件的最後修改時間 * @param path * @throws IOException */ public void GetLTime(String path) throws IOException { Configuration conf = new Configuration(); FileSystem hdfs = FileSystem.get(conf); Path fpath =new Path(path); FileStatus fileStatus=hdfs.getFileStatus(fpath); long modiTime=fileStatus.getModificationTime(); Date date = new Date(modiTime); System.out.println("file1.txt change time is"+date); hdfs.close(); } /** * 獲取文件信息 * @param path * @throws IOException */ public void GetFileInfo(String path) throws IOException { Configuration conf = new Configuration(); FileSystem hdfs = FileSystem.get(conf); Path fpath =new Path(path); FileStatus fileStatus=hdfs.getFileStatus(fpath); System.out.println("文件路徑："+fileStatus.getPath()); System.out.println("塊的大小："+fileStatus.getBlockSize()); System.out.println("文件全部者："+fileStatus.getOwner()+":"+fileStatus.getGroup()); System.out.println("文件權限："+fileStatus.getPermission()); System.out.println("文件長度："+fileStatus.getLen()); System.out.println("備份數："+fileStatus.getReplication()); System.out.println("修改時間："+fileStatus.getModificationTime()); hdfs.close(); } /** * 獲取目錄下的全部文件 * @param path * @throws IOException */ public void GetAllFile(String path) throws IOException { Configuration conf = new Configuration(); FileSystem hdfs = FileSystem.get(conf); Path fpath =new Path(path); FileStatus stats[]=hdfs.listStatus(fpath); for(int i = 0; i < stats.length; ++i) { System.out.println(stats[i].getPath().toString()); } hdfs.close(); } /** * 查看文件所在集羣的位置 * @param path * @throws IOException */ public void FindFilePost(String path) throws IOException { Configuration conf = new Configuration(); FileSystem hdfs = FileSystem.get(conf); Path fpath =new Path(path); FileStatus fileStatus=hdfs.getFileStatus(fpath); BlockLocation[] blkLocations = hdfs.getFileBlockLocations(fileStatus,0,fileStatus.getLen()); int blockLen = blkLocations.length; for(int i=0;i<blockLen;i++){ String[] hosts = blkLocations[i].getHosts(); System.out.println("block_"+i+"_location:"+hosts[0]); } hdfs.close(); } }

　　

package com.duking.test;

import java.io.IOException;

import com.duking.util.HDFSUtil;


public class HDFSTest {

	public static void main(String[] args) throws IOException {
		
		
		HDFSUtil Hdfs = new HDFSUtil();
		
		//Hdfs.CreateFile("/user/duking/testfile2.txt","hello,world");
		
		//Hdfs.CreateDir("/user/test");
		
		//Hdfs.RenameFile("/user/duking/testfile.txt", "/user/duking/test.txt");
		
		//Hdfs.DeleteFile("/user/duking/test.txt");
		
		//Hdfs.CheckFile("/user/hadoop/input/protocols");
		
		//Hdfs.GetLTime("/user/hadoop/input/protocols");
		
		//Hdfs.GetFileInfo("/user/hadoop/input/protocols");
		
		//Hdfs.GetAllFile("/user/hadoop/input/");
		
		Hdfs.FindFilePost("/user/hadoop/input/protocols");
		
		System.out.println("Runing is over!!");
	}
}

　　更多HDFS的操做請查看HDFS JAVA API

　　　　http://hadoop.apache.org/docs/stable/api/index.html

　　

HDFS Users Guide

http://hadoop.apache.org/docs/stable/hadoop-project-dist/hadoop-hdfs/HdfsUserGuide.html