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

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