HDFS上创建包，读取，删除，下载，上传，读取，追加，设置权限。

package com.zhiyou.bd23;
import java.io.FileNotFoundException;
import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.UnsupportedFileSystemException;
import org.apache.hadoop.fs.permission.FsAction;
import org.apache.hadoop.fs.permission.FsPermission;
import org.apache.hadoop.security.AccessControlException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


public class HdfsUtils {
	private static Logger logger = LoggerFactory.getLogger(HdfsUtils.class);
	
	public static Configuration configuration = new Configuration();
	public static FileSystem hdfs;
	//静态代码块中初始化hdfs对象
	static {
		try {
			hdfs = FileSystem.get(configuration);
		} catch (Exception e) {
			logger.error("hdfs连接异常");
			e.printStackTrace();
		}
	}
	//在hdfs上创建一个人目录
	public static void createDir(String path) {
		Path p = new Path(path);
		try {
			boolean result = hdfs.mkdirs(p);
			if (result) {
				logger.info("创建成功了"+path);
			}
		} catch (Exception e) {
			logger.error("创建目录异常"+path);
			logger.debug(e.getMessage());
			logger.debug(e.getStackTrace().toString());
		}
	}
	//删除一个目录或文件，删除之前判断参数路径是目录还是文件，删除成功后提示删除目录或文件成功
	public static void deleteDir(String path) {
		Path p =new Path(path);
		try {
			if (hdfs.exists(p)) {
				if (hdfs.isFile(p)) {
					logger.info("删除文件"+path);
				}else {
					logger.info("删除目录"+path);
				}
				hdfs.delete(p,true);
			}else {
				logger.info("路径不存在"+path);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	//把hdfs上的文件下载到本地路径
	public static void downloadFromHdfs(String hdfsPath,String localPath) {
		Path src = new Path(hdfsPath);
		Path dst = new Path(localPath);
		try {
			hdfs.copyToLocalFile(false,src,dst,true);
			logger.info("下载成功"+localPath);
		} catch (Exception e) {
			logger.debug("下载异常");
			e.printStackTrace();
		}
	}
	//把文件上传到hdfs上
	public static void uploadFromHdfs(String localPath,String hdfsPath) {
		Path dst = new Path(localPath);
		Path src = new Path(hdfsPath);
		try {
			hdfs.copyFromLocalFile(dst, src);
			logger.info("上传成功"+hdfsPath);
		} catch (Exception e) {
			logger.debug("上传异常");
			e.printStackTrace();
		}
	}
	//读取hdfs上的文件
	public static void readFileOnHdfs(String path) {
		Path p =new Path(path);
		try {
			if (hdfs.exists(p)) {
				if (hdfs.isFile(p)) {
					FSDataInputStream inputStream = hdfs.open(p);
					String str = inputStream.readUTF();
					logger.info(str);
					//inputStream.readInt();
					int lineNumber = 1;
					logger.info("开始");
				    while(str!=null) {
				    	logger.info(lineNumber+":"+str);
				    	lineNumber +=1;
				    	try {
					    	str = inputStream.readUTF();
						} catch (Exception e) {
					    	logger.info("文件读取结束");
					    	str = null;
						}
				    }
				}else {
					logger.info(path+"它不是文件");
				}
			}else {
				logger.info("不存在"+path);
			}
		} 
		catch (Exception e) {
			e.printStackTrace();
		}
	}
	//往hdfs上的一个文件后面追加三行数据内容
	public static void appendContentToFile(String path) {
		Path P = new Path(path);
		try {
			
			FSDataOutputStream outputStream = hdfs.append(P);
			outputStream.writeUTF("大数据");
			outputStream.writeUTF("java");
			outputStream.writeUTF("sh");
			outputStream.hflush();
			logger.info("追加成功");
		} catch (Exception e) {
			logger.info("追加失败");
			e.printStackTrace();
		}
	}
	//hdfs的连接关闭
	public static void close() {
		if (hdfs !=null) {
			try {
				hdfs.close();
				logger.info("关闭和hdfs的连接");
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
	}
	public static Configuration con = new Configuration();
	public static FileSystem system ;
	static {
		try {
			system= FileSystem.get(con);
		} catch (Exception e) {
			// TODO: handle exception
			e.printStackTrace();
		}
	}
	//设置hdfs上文件的权限
	public static void setPermission(String path) throws Exception {
		Path p =new Path(path);
		FsPermission permission= new FsPermission(FsAction.ALL,FsAction.ALL,FsAction.ALL);
		if (hdfs.exists(p)) {
			hdfs.setPermission(p, permission);
			logger.info("权限设置成功");
		}else {
			logger.info("给定路径不存在"+path);
		}
	}
	public static void getPathStatus(String path){
		Path p = new Path(path);
		FileStatus fileStatus ;
		try {
			fileStatus= hdfs.getFileLinkStatus(p);
			logger.info(fileStatus.toString());
			logger.info("getPermission:"+fileStatus.getPermission());
		} catch (Exception e) {
			// TODO: handle exception
		}
	}
	public static void listPathStatus(String path) {
		Path p = new Path(path);
		FileStatus[] fileStatus;
		try {
			if (hdfs.isDirectory(p)) {
				fileStatus = hdfs.listStatus(p);
				for (FileStatus fs : fileStatus) {
					logger.info(fs.toString());
				}
			}else {
				logger.info("给定的路径不是一个目录"+path);
			}
			
		} catch (Exception e) {
			// TODO: handle exception
		}
	}
	public static void main(String[] args) throws Exception {
//		createDir("/bd23");
		deleteDir("/secondarysortoutput");
//		downloadFromHdfs("/fromjava.txt", "C:\\Users\\zc\\Desktop\\yyyy.txt");
//		uploadFromHdfs("C:\\Users\\zc\\Desktop\\zzz.txt", "/ttt.txt");
//		readFileOnHdfs("/zxcvb.txt");
//		appendContentToFile("/fromjava.txt");
//		setPermission("/fromjava.txt");
//		getPathStatus("/fromjava.txt");
//		listPathStatus("/fromjava.txt");
		close();
	}
}