编写Java代码对HDFS进行增删改查操作代码实例
本文实例为大家分享了Java代码对HDFS进行增删改查操作的具体代码，供大家参考，具体内容如下
importjava.io.File;
importjava.io.FileOutputStream;
importjava.io.IOException;
importjava.net.URI;
importorg.apache.commons.compress.utils.IOUtils;
importorg.apache.hadoop.conf.Configuration;
importorg.apache.hadoop.fs.BlockLocation;
importorg.apache.hadoop.fs.FSDataInputStream;
importorg.apache.hadoop.fs.FSDataOutputStream;
importorg.apache.hadoop.fs.FileStatus;
importorg.apache.hadoop.fs.FileSystem;
importorg.apache.hadoop.fs.Path;
publicclassFileOpreation{
publicstaticvoidmain(String[]args)throwsIOException{
//CreateFile();
//DeleteFile();
//CopyFileToHDFS();
//MkDirs();
//DelDirs();
ListDirectory();
DownLoad();
}
publicstaticvoidCreateFile()throwsIOException{
Stringuri="hdfs://Alvis:9000";
Configurationconfiguration=newConfiguration();
FileSystemfSystem=FileSystem.get(URI.create(uri),configuration);
byte[]file_content_buff="hellohadoopworld,testwritefile!\n".getBytes();
Pathdfs=newPath("/home/test.txt");
FSDataOutputStreamoutputStream=fSystem.create(dfs);
outputStream.write(file_content_buff.length);
}
publicFileOpreation(){
//TODOAuto-generatedconstructorstub
}publicstaticvoidDeleteFile()throwsIOException{
Stringuri="hdfs://Alvis:9000";
Configurationconfiguration=newConfiguration();
FileSystemfSystem=FileSystem.get(URI.create(uri),configuration);
Pathdeletf=newPath("/home/test.txt");
booleandelResult=fSystem.delete(deletf,true);
System.out.println(delResult==true?"删除成功":"删除失败");
}
publicstaticvoidCopyFileToHDFS()throwsIOException{
Stringuri="hdfs://Alvis:9000";
Configurationconfiguration=newConfiguration();
FileSystemfSystem=FileSystem.get(URI.create(uri),configuration);
Pathsrc=newPath("E:\\SerializationTest\\APITest.txt");
Pathdest_src=newPath("/home");
fSystem.copyFromLocalFile(src,dest_src);
}
publicstaticvoidMkDirs()throwsIOException{
Stringuri="hdfs://Alvis:9000";
Configurationconfiguration=newConfiguration();
FileSystemfSystem=FileSystem.get(URI.create(uri),configuration);
Pathsrc=newPath("/Test");
fSystem.mkdirs(src);
}
publicstaticvoidDelDirs()throwsIOException{
Stringuri="hdfs://Alvis:9000";
Configurationconfiguration=newConfiguration();
FileSystemfSystem=FileSystem.get(URI.create(uri),configuration);
Pathsrc=newPath("/Test");
fSystem.delete(src);
}
publicstaticvoidListDirectory()throwsIOException{
Stringuri="hdfs://Alvis:9000";
Configurationconfiguration=newConfiguration();
FileSystemfSystem=FileSystem.get(URI.create(uri),configuration);
FileStatus[]fStatus=fSystem.listStatus(newPath("/output"));
for(FileStatusstatus:fStatus)
if(status.isFile()){
System.out.println("文件路径："+status.getPath().toString());
System.out.println("文件路径getReplication："+status.getReplication());
System.out.println("文件路径getBlockSize:"+status.getBlockSize());
BlockLocation[]blockLocations=fSystem.getFileBlockLocations(status,0,status.getBlockSize());
for(BlockLocationlocation:blockLocations){
System.out.println("主机名："+location.getHosts()[0]);
System.out.println("主机名："+location.getNames()[0]);
}
}
else{
System.out.println("directory:"+status.getPath().toString());
}
}
publicstaticvoidDownLoad()throwsIOException{
Configurationconfiguration=newConfiguration();
configuration.set("fs.defaultFS","hdfs://Alvis:9000");
FileSystemfSystem=FileSystem.get(configuration);
FSDataInputStreaminputStream=fSystem.open(newPath("/input/wc.jar"));
FileOutputStreamoutputStream=newFileOutputStream(newFile("E:\\LearnLife\\DownLoad\\wc.jar"));
IOUtils.copy(inputStream,outputStream);
System.out.println("下载成功！");
}
}
思想：
一、定义虚拟机接口
二、先拿到HDFS远程调用接口对象Configuration
三、定义分布式文件系统FileSystem对象获取对象
四、给定路径
五、用FileSystem对象调用操作
以上所述是小编给大家介绍的Java代码对HDFS进行增删改查操作详解整合，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对毛票票网站的支持！