标签：win blocks windows color 操作 org cal 上传 image
学习用java进行的常用hdfs操作
hadoop2.6.4
win7 下的eclipse环境调试已经配置好，参考前面的文章
1 package hdfs; 2 3 import java.io.IOException; 4 5 import org.apache.hadoop.conf.Configuration; 6 import org.apache.hadoop.fs.FileSystem; 7 import org.apache.hadoop.fs.Path; 8 9 /** 10 * 11 * @author Administrator 12 * 创建文件夹,如果不存在 13 */ 14 public class CreateFolder { 15 16 public static void main(String[] args) throws IOException { 17 Configuration conf =new Configuration(); 18 conf.set("fs.defaultFS", "hdfs://ssmaster:9000/"); 19 FileSystem fs = FileSystem.get(conf) ; 20 Path path = new Path("/output"); 21 22 if(! fs.exists(path)){ 23 fs.mkdirs(path); 24 } 25 } 26 }
以流的方式下载文件
1 package hdfs; 2 3 import java.io.FileNotFoundException; 4 import java.io.FileOutputStream; 5 import java.io.IOException; 6 7 import org.apache.commons.compress.utils.IOUtils; 8 import org.apache.hadoop.conf.Configuration; 9 import org.apache.hadoop.fs.FSDataInputStream; 10 import org.apache.hadoop.fs.FileSystem; 11 import org.apache.hadoop.fs.Path; 12 13 /** 14 * 功能： 将 hdfs://ssmaster:9000/data/paper.txt下载到Windows下c:\paper.txt 15 * 调用方式：windows下执行,eclipse中执行 16 */ 17 18 public class Down_Load { 19 20 public static void main(String[] args) { 21 22 Configuration conf =new Configuration(); 23 conf.set("fs.defaultFS", "hdfs://ssmaster:9000/"); 24 25 FileSystem fs = null; 26 Path src = null; 27 FSDataInputStream in = null; 28 FileOutputStream out = null; 29 30 src = new Path("hdfs://ssmaster:9000/data/paper.txt" ); 31 32 try { 33 34 fs = FileSystem.get(conf) ; 35 in = fs.open(src); 36 37 } catch (IOException e) { 38 e.printStackTrace(); 39 } 40 41 try { 42 out = new FileOutputStream ("c:\\paper.txt"); //等效 c:/paper.txt 43 } catch (FileNotFoundException e) { 44 e.printStackTrace(); 45 } 46 47 try { 48 IOUtils.copy(in, out); 49 } catch (IOException e) { 50 e.printStackTrace(); 51 } 52 53 } 54 }
1 package hdfs; 2 3 import java.io.IOException; 4 5 import org.apache.hadoop.conf.Configuration; 6 import org.apache.hadoop.fs.FileSystem; 7 import org.apache.hadoop.fs.Path; 8 9 /** 10 * 11 * @author Administrator 12 * 上传本地文件 13 */ 14 public class UploadFile { 15 16 public static void main(String[] args) throws IOException { 17 Configuration conf =new Configuration(); 18 conf.set("fs.defaultFS", "hdfs://ssmaster:9000/"); 19 FileSystem fs = FileSystem.get(conf) ; 20 Path path = new Path("/output"); 21 Path src = new Path("c:/paper.txt"); 22 23 fs.copyFromLocalFile(false, true, src, path); 24 25 } 26 }
1 package hdfs; 2 3 import java.io.IOException; 4 5 import org.apache.hadoop.conf.Configuration; 6 import org.apache.hadoop.fs.FileSystem; 7 import org.apache.hadoop.fs.Path; 8 9 /** 10 * 11 * @author Administrator 12 * 上传本地文件 13 */ 14 public class DownFile { 15 16 public static void main(String[] args) throws IOException { 17 Configuration conf =new Configuration(); 18 conf.set("fs.defaultFS", "hdfs://ssmaster:9000/"); 19 FileSystem fs = FileSystem.get(conf) ; 20 Path hdfs = new Path("/output/paper.txt"); 21 Path win7 = new Path("c:/paper_download.txt"); 22 23 fs.copyToLocalFile(hdfs, win7); 24 25 } 26 }
1 package hdfs; 2 3 import java.io.IOException; 4 5 import org.apache.hadoop.conf.Configuration; 6 import org.apache.hadoop.fs.FileSystem; 7 import org.apache.hadoop.fs.Path; 8 9 /** 10 * 11 * @author Administrator 12 * 删除hdfs文件,如何文件不存在，也运行正常 13 */ 14 public class DeleteFile { 15 16 public static void main(String[] args) throws IOException { 17 Configuration conf =new Configuration(); 18 conf.set("fs.defaultFS", "hdfs://ssmaster:9000/"); 19 FileSystem fs = FileSystem.get(conf) ; 20 Path hdfs = new Path("/output/paper.txt"); 21 fs.delete(hdfs, true); 22 23 } 24 }
1 package hdfs; 2 3 import java.io.IOException; 4 5 import org.apache.hadoop.conf.Configuration; 6 import org.apache.hadoop.fs.FileStatus; 7 import org.apache.hadoop.fs.FileSystem; 8 import org.apache.hadoop.fs.Path; 9 10 /** 11 * 12 * @author Administrator 13 * 显示某个目录下的文件 14 */ 15 public class ListFiles { 16 17 public static void main(String[] args) throws IOException { 18 Configuration conf =new Configuration(); 19 conf.set("fs.defaultFS", "hdfs://ssmaster:9000/"); 20 FileSystem fs = FileSystem.get(conf) ; 21 Path hdfs = new Path("/"); 22 23 24 FileStatus [] files = fs.listStatus(hdfs); 25 for (FileStatus file:files) { 26 27 System.out.print(file.getPath().getName()); 28 System.out.print("\t"+ file.isDirectory()); 29 System.out.print("\t"+ file.getOwner()); 30 System.out.print("\n"); 31 } 32 33 } 34 }
HDFS JAVA API 调用初步学会使用。该篇章翻过去，后续用什么再学
后续：
有空将文件系统的常用操作实现，搜索、递归显示、查看文件内容
标签：win blocks windows color 操作 org cal 上传 image
原文地址：http://www.cnblogs.com/sunzebo/p/5997755.html
