用Java在hdfs中写入文件 [英] Write a file in hdfs with Java

问题描述

我想在 HDFS 中创建一个文件并在其中写入数据.我使用了这个代码:

I want to create a file in HDFS and write data in that. I used this code:

Configuration config = new Configuration();     
FileSystem fs = FileSystem.get(config); 
Path filenamePath = new Path("input.txt");  
try {
    if (fs.exists(filenamePath)) {
        fs.delete(filenamePath, true);
    }

    FSDataOutputStream fin = fs.create(filenamePath);
    fin.writeUTF("hello");
    fin.close();
}

它创建了文件，但没有在其中写入任何内容.我搜索了很多但是没有找到任何东西.我的问题是什么?在 HDFS 中写入需要任何权限吗?

It creates the file, but it does't write anything in it. I searched a lot but didn't find anything. What is my problem? Do I need any permission to write in HDFS?

谢谢.

推荐答案

@Tariq 的一个替代方案，你可以在获取文件系统时传递 URI

an alternative to @Tariq's asnwer you could pass the URI when getting the filesystem

import org.apache.hadoop.fs.FileSystem
import org.apache.hadoop.conf.Configuration
import java.net.URI
import org.apache.hadoop.fs.Path
import org.apache.hadoop.util.Progressable
import java.io.BufferedWriter
import java.io.OutputStreamWriter

Configuration configuration = new Configuration();
FileSystem hdfs = FileSystem.get( new URI( "hdfs://localhost:54310" ), configuration );
Path file = new Path("hdfs://localhost:54310/s2013/batch/table.html");
if ( hdfs.exists( file )) { hdfs.delete( file, true ); } 
OutputStream os = hdfs.create( file,
    new Progressable() {
        public void progress() {
            out.println("...bytes written: [ "+bytesWritten+" ]");
        } });
BufferedWriter br = new BufferedWriter( new OutputStreamWriter( os, "UTF-8" ) );
br.write("Hello World");
br.close();
hdfs.close();

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