HDFSAPI

package com.hellohadoop;import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hdfs.DistributedFileSystem;
import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
import org.apache.hadoop.fs.BlockLocation;
import org.apache.hadoop.fs.FSDataOutputStream;public class FileOperator {static Configuration conf;static FileSystem hdfs;public static void main(String[] args) throws Exception{Init();Upload();
// Create();
// CreateFolder();
// Rename();
// Delete();
// IsExist();
// GetTime();
// GetAllFiles();
// GetLocations();
// GetAllHosts();
}// 初始化public static void Init() throws Exception{conf &＃61; new Configuration();hdfs &＃61; FileSystem.get(conf); }// 上传文件public static void Upload() throws Exception{// 本地文件Path src &＃61; new Path("F:\\Hadoop\\DataFiles\\data.txt");// 上传路径Path dst &＃61; new Path("hdfs://master:9000/user/Administrator/");// 上传文件
hdfs.copyFromLocalFile(src, dst);System.out.println("Upload to " &＃43; conf.get("fs.default.name"));}// 创建文件public static void Create() throws Exception{byte[] buff &＃61; "Hello Hadoop!".getBytes();// 新建文件路径Path dfs &＃61; new Path("hdfs://master:9000/user/Administrator/hello");FSDataOutputStream outputStream &＃61; hdfs.create(dfs);outputStream.write(buff, 0, buff.length);System.out.println("Created!");}// 创建文件夹public static void CreateFolder() throws Exception{// 新建文件路径Path dfs &＃61; new Path("hdfs://master:9000/user/Administrator/helloDir");hdfs.mkdirs(dfs);System.out.println("Created!");}// 重新命名HDFS文件public static void Rename() throws Exception{Path of &＃61; new Path("hdfs://master:9000/user/Administrator/data.txt");Path nf &＃61; new Path("hdfs://master:9000/user/Administrator/newdata.txt");boolean isOk &＃61; hdfs.rename(of, nf);String res &＃61; isOk? "Yes": "No";System.out.println("Result:" &＃43; res);}// 删除HDFS文件public static void Delete() throws Exception{Path file &＃61; new Path("hdfs://master:9000/user/Administrator/helloDir");
// hdfs.delete(file, false);// 第二个为是否递归删除,如果目录下面有文件,是否递归删除为false会报错hdfs.delete(file, true);}// 查看某个文件是否存在public static void IsExist() throws IOException{Path file &＃61; new Path("hdfs://master:9000/user/Administrator/hello1");String res &＃61; hdfs.exists(file)? "Yes": "No";System.out.println("Result:" &＃43; res);}// 查看文件最后修改时间public static void GetTime() throws Exception{Path file &＃61; new Path("hdfs://master:9000/user/Administrator/hello");FileStatus fs &＃61; hdfs.getFileStatus(file);long mTime &＃61; fs.getModificationTime();SimpleDateFormat sdf &＃61; new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");String sTime &＃61; sdf.format(new Date(mTime));System.out.println("Modified Time:" &＃43; sTime);}// 递归查看文件目录public static void GetAllFiles() throws Exception{Path file &＃61; new Path("hdfs://master:9000/");AllFile(file);}public static void AllFile(Path p) throws Exception{FileStatus[] fs &＃61; hdfs.listStatus(p);for (FileStatus f: fs){// 是文件输出路径if (hdfs.isFile(f.getPath())){System.out.println(f.getPath());}// 是目录继续递归else{System.out.println();System.out.println(f.getPath() &＃43; ":");AllFile(f.getPath());}}}// 查看文件在HDFS中的位置public static void GetLocations() throws Exception{Path file &＃61; new Path("hdfs://master:9000/user/Administrator/stsme_20150330.sql");FileStatus fs &＃61; hdfs.getFileStatus(file);BlockLocation[] blk &＃61; hdfs.getFileBlockLocations(fs, 0, fs.getLen());for(int i&＃61;0; i){String[] host &＃61; blk[i].getHosts();System.out.println("Block " &＃43; i &＃43; " Location:" &＃43; host[0]);} }// 查看HDFS集群上所有节点public static void GetAllHosts() throws Exception{DistributedFileSystem dfs &＃61; (DistributedFileSystem) hdfs;DatanodeInfo[] dns &＃61; dfs.getDataNodeStats();for (int i&＃61;0; i){System.out.println("Datanode " &＃43; i &＃43; " Name:" &＃43; dns[i].getHostName());}}}