With mimim you can directly play an mp3 from a url.

minim_play_spotifypreview.pde

// https://developer.spotify.com/web-api/get-track/
// http://code.compartmental.net/minim/minim_method_loadfile.html

import ddf.minim.*;
import ddf.minim.effects.*;

Minim minim;
AudioPlayer groove;

void setup()
{
  size(512, 200, P3D);

  minim = new Minim(this);
  groove = minim.loadFile("http://d318706lgtcm8e.cloudfront.net/mp3-preview/f454c8224828e21fa146af84916fd22cb89cedc6"); //, 2048);
  groove.play();
}

void draw()
{
  background(0);
  
  stroke(255);
  
  for(int i = 0; i < groove.bufferSize() - 1; i++)
  {
    line(i, 50  + groove.left.get(i)*50,  i+1, 50  + groove.left.get(i+1)*50);
    line(i, 150 + groove.right.get(i)*50, i+1, 150 + groove.right.get(i+1)*50);
  }
}