编写Java代码对HDFS进行增删改查操作代码实例

Arce

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，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CodeAE代码之家网站的支持！
原文链接：https://blog.csdn.net/qq_41395106/article/details/89036014