HDFS For Java详解大数据

package cn.hwadee.wuyang.hdfs.utils; 
import java.io.ByteArrayOutputStream; 
import java.io.IOException; 
import java.io.OutputStream; 
import java.net.URI; 
import org.apache.hadoop.conf.Configuration; 
import org.apache.hadoop.fs.FSDataInputStream; 
import org.apache.hadoop.fs.FileStatus; 
import org.apache.hadoop.fs.FileSystem; 
import org.apache.hadoop.fs.Path; 
import org.apache.hadoop.io.IOUtils; 
public class ConfigurationUtil { 
private static String url = "hdfs://192.168.193.201:9000"; 
private static String user = "wuyang"; 
private static FileSystem fs; 
/** 
* 获取文件系统 
* @return 
*/ 
public static FileSystem getFileSystem(){ 
Configuration conf = new Configuration(); 
try { 
return FileSystem.get(URI.create(url), conf, user); 
} catch (Exception e) { 
return null; 
} 
} 
/** 
* 创建文件夹 
* @param path 
* @throws IOException  
*/ 
public static Boolean createFileDir(Path path) throws IOException{ 
Configuration conf = new Configuration(); 
try { 
fs = FileSystem.get(URI.create(url), conf, user); 
if(!fs.exists(path)){ 
fs.mkdirs(path); 
System.out.println(path.getName()+"文件夹创建成功！！！"); 
return true; 
} 
return false; 
} catch (Exception e) { 
e.getMessage(); 
return false; 
}finally { 
fs.close(); 
} 
} 
/** 
* 删除文件 
* @param path 
* @throws IOException  
*/ 
public static Boolean deleteFile(Path path) throws IOException{ 
Configuration conf = new Configuration(); 
try { 
fs = FileSystem.get(URI.create(url), conf, user); 
if(fs.exists(path)){ 
fs.delete(path, true); 
System.out.println(path.getName()+"文件删除成功！！！"); 
return true; 
} 
return false; 
} catch (Exception e) { 
e.getMessage(); 
return false; 
}finally { 
fs.close(); 
} 
} 
/** 
* 重命名 
* @param name1 
* @param name2 
* @throws IOException  
*/ 
public static Boolean fileRename(Path name1,Path name2) throws IOException { 
Configuration conf = new Configuration(); 
try { 
fs = FileSystem.get(URI.create(url), conf, user); 
if (fs.exists(name1)) { 
fs.rename(name1, name2); 
System.out.println(name2.getName()+"替换"+name1.getName()+"成功!!!"); 
return true; 
} 
return false; 
} catch (Exception e) { 
e.getMessage(); 
return false; 
}finally { 
fs.close(); 
} 
} 
/** 
* 创建文件 
* @param path 
* @return 
*/ 
public static Boolean createFile(Path path){ 
Configuration conf = new Configuration(); 
try { 
fs = FileSystem.get(URI.create(url), conf, user); 
if(!fs.exists(path)){ 
fs.create(path); 
System.out.println(path.getName()+"文件创建成功！！！"); 
return true; 
}else{ 
System.out.println(path.getName()+"文件已经存在！！！"); 
return false; 
} 
}catch (Exception e) { 
e.getMessage(); 
return false; 
}finally { 
try { 
fs.close(); 
} catch (IOException e) { 
e.getMessage(); 
} 
} 
} 
/** 
* 获取path下文件 
* @param path 
* @return 
*/ 
public static FileStatus[] listFile(Path path){ 
Configuration conf = new Configuration(); 
try { 
fs = FileSystem.get(URI.create(url), conf, user); 
if(fs.exists(path)){ 
FileStatus[] list = fs.listStatus(path); 
System.out.println("文件长度:"+list.length); 
return list; 
} 
return null; 
} catch (Exception e) { 
e.getMessage(); 
return null; 
}    
} 
/** 
* 从hdfs上下载文件 
* @param hdfspath 
* @param locationpath 
* @return 
*/ 
public static Boolean downLoadFileFromHDFS(Path hdfspath,Path locationpath){ 
Configuration conf = new Configuration(); 
try { 
fs = FileSystem.get(URI.create(url), conf, user); 
if(fs.exists(hdfspath)){ 
fs.copyToLocalFile(hdfspath, locationpath); 
System.out.println("download: from" + hdfspath.getName() + " to " + locationpath.getName()); 
return true; 
} 
return false; 
} catch (Exception e) { 
e.getMessage(); 
return false; 
}finally { 
try { 
fs.close(); 
} catch (IOException e) { 
e.getMessage(); 
} 
}    
} 
/** 
* 拷贝文件到HDFS 
* @param local 
* @param remote 
* @throws IOException 
*/ 
public static Boolean copyFileToHDFS(String local, String remote) throws IOException { 
Configuration conf = new Configuration(); 
try { 
fs = FileSystem.get(URI.create(url), conf, user); 
fs.copyFromLocalFile(new Path(local), new Path(remote)); 
System.out.println("copy from: " + local + " to " + remote); 
return true; 
} catch (Exception e) { 
e.getMessage(); 
return false; 
}finally { 
try { 
fs.close(); 
} catch (IOException e) { 
e.getMessage(); 
} 
}    
} 
/** 
* 查看文件中的内容 
* @param remoteFile 
* @return 
* @throws IOException 
* @throws InterruptedException  
*/ 
public static String catFile(String remoteFile) throws IOException, InterruptedException { 
Path path = new Path(remoteFile); 
Configuration conf = new Configuration(); 
fs = FileSystem.get(URI.create(url), conf, user); 
FSDataInputStream fsdis = null; 
OutputStream baos = new ByteArrayOutputStream(); 
String str = null; 
try { 
fsdis = fs.open(path); 
IOUtils.copyBytes(fsdis, baos, 4096, false); 
str = baos.toString(); 
} finally { 
IOUtils.closeStream(fsdis); 
fs.close(); 
} 
return str; 
} 
}