hadoop hdfs java api操作

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 {

	/**
	 * 创建一个文件
	 * path:路径   txt：文件类容
	 * */
	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!!");
	}

      //上传本地文件
      public static void uploadFile(String src,String dst) throws IOException{
          Configuration conf = new Configuration();
          FileSystem fs = FileSystem.get(conf);
 　　　　　 Path srcPath = new Path(src); //原路径
          Path dstPath = new Path(dst); //目标路径
          //调用文件系统的文件复制函数,前面参数是指是否删除原文件，true为删除，默认为false
          fs.copyFromLocalFile(false,srcPath, dstPath);

          //打印文件路径
          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();
      }

 /** * 创建文件夹 * @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(); } /** * 从命名文件 * @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); //旧的文件名 Path topath=new Path(newpath); //新的文件名 boolean isRename=hdfs.rename(frpaht, topath); String result=isRename?"成功":"失败"; System.out.println("文件重命名结果为："+result); hdfs.close(); } /** * 删除文件 或者目录 * @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(); } /** * 判断文件或目录是否存在 * @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文件的最后修改时间 * @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(); } /** * 获取文件信息 * @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("文件路径："+fileStatus.getPath()); System.out.println("块的大小："+fileStatus.getBlockSize()); System.out.println("文件所有者："+fileStatus.getOwner()+":"+fileStatus.getGroup()); System.out.println("文件权限："+fileStatus.getPermission()); System.out.println("文件长度："+fileStatus.getLen()); System.out.println("备份数："+fileStatus.getReplication()); System.out.println("修改时间："+fileStatus.getModificationTime()); hdfs.close(); } /** * 获取目录下的所有文件 * @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(); } /** * 查看文件所在集群的位置 * @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的操作请查看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