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
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import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.URI;
import org.apache.commons.compress.utils.IOUtils;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.BlockLocation;
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;
public class FileOpreation {
public static void main(String[] args) throws IOException {
//CreateFile();
//DeleteFile();
//CopyFileToHDFS();
//MkDirs();
//DelDirs();
ListDirectory();
DownLoad();
}
public static void CreateFile() throws IOException {
String uri = "hdfs://Alvis:9000";
Configuration configuration =new Configuration();
FileSystem fSystem = FileSystem.get(URI.create(uri), configuration);
byte[] file_content_buff="hello hadoop world, test write file !\n".getBytes();
Path dfs = new Path("/home/test.txt");
FSDataOutputStream outputStream = fSystem.create(dfs);
outputStream.write(file_content_buff.length);
}
public FileOpreation() {
// TODO Auto-generated constructor stub
}public static void DeleteFile() throws IOException {
String uri = "hdfs://Alvis:9000";
Configuration configuration =new Configuration();
FileSystem fSystem = FileSystem.get(URI.create(uri), configuration);
Path deletf = new Path("/home/test.txt");
boolean delResult = fSystem.delete(deletf,true);
System.out.println(delResult==true?"删除成功":"删除失败");
}
public static void CopyFileToHDFS() throws IOException {
String uri = "hdfs://Alvis:9000";
Configuration configuration =new Configuration();
FileSystem fSystem = FileSystem.get(URI.create(uri), configuration);
Path src = new Path("E:\\SerializationTest\\APITest.txt");
Path dest_src = new Path("/home");
fSystem.copyFromLocalFile(src, dest_src);
}
public static void MkDirs() throws IOException {
String uri = "hdfs://Alvis:9000";
Configuration configuration =new Configuration();
FileSystem fSystem = FileSystem.get(URI.create(uri), configuration);
Path src = new Path("/Test");
fSystem.mkdirs(src);
}
public static void DelDirs() throws IOException {
String uri = "hdfs://Alvis:9000";
Configuration configuration = new Configuration();
FileSystem fSystem = FileSystem.get(URI.create(uri), configuration);
Path src = new Path("/Test");
fSystem.delete(src);
}
public static void ListDirectory() throws IOException {
String uri = "hdfs://Alvis:9000";
Configuration configuration = new Configuration();
FileSystem fSystem = FileSystem.get(URI.create(uri), configuration);
FileStatus[] fStatus = fSystem.listStatus(new Path("/output"));
for(FileStatus status : 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(BlockLocation location : 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());
}
}
public static void DownLoad() throws IOException {
Configuration configuration = new Configuration();
configuration.set("fs.defaultFS", "hdfs://Alvis:9000");
FileSystem fSystem =FileSystem.get(configuration);
FSDataInputStream inputStream =fSystem.open( new Path("/input/wc.jar"));
FileOutputStream outputStream = new FileOutputStream(new File("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创新互联网站的支持！
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