Why Hadoop FileSystem.get method needs to know full URI and not just scheme

Question

Is it possible to use an instance of Hadoop FileSystem created from any valid hdfs url to be used again for reading and writing different hdfs urls.I have tried the following

String url1 = "hdfs://localhost:54310/file1.txt";
String url2 = "hdfs://localhost:54310/file2.txt";
String url3 = "hdfs://localhost:54310/file3.txt";

//Creating filesystem using url1
FileSystem fileSystem = FileSystem.get(URI.create(url1), conf);

//Using same filesystem with url2 and url3  
InputStream in = fileSystem.open(new Path(url2));
OutputStream out = fileSystem.create(new Path(url3));

This works.But will this cause any other issues.

Answer 1

You can certainly create a single FileSystem with your scheme and adress and then get it via the FileSystem.

Configuration conf = new Configuration();
conf.set("fs.default.name","hdfs://localhost:54310");
FileSystem fs = FileSystem.get(conf);
InputStream is = fs.open(new Path("/file1.txt"));