LastfmArtistImages.java

import java.io.*;
import java.net.*;
import java.util.Scanner;
import java.nio.charset.StandardCharsets;

public class getURL {
  public static void main(String[] args) {
    String artistOrMbid = "";

    System.out.print("Enter artist name>");
    Scanner input = new Scanner(System.in);
    artistOrMbid = input.nextLine();
    input.close();

    // Pull the artist image url from the last.fm artist page
    String sImageURL = "", sArtistURL = "";
    try {
      sArtistURL = "https://www.last.fm/music/"+URLEncoder.encode(artistOrMbid, StandardCharsets.UTF_8.toString());
    } catch (UnsupportedEncodingException e) {
      // This should never happen for us
    }
    String sHTML = getWebPage(sArtistURL);
    if (sHTML != null) {
      int iImgUrlIndex = sHTML.indexOf("+images/");
      if (iImgUrlIndex > 0) {
        int iStartTrim = iImgUrlIndex+8; // ("+images/").length = 8
        int iEndTrim = sHTML.indexOf("\"", iStartTrim);
        String sImageID = sHTML.substring(iStartTrim, iEndTrim);
        sImageURL = "https://lastfm.freetls.fastly.net/i/u/770x0/"+
          sImageID+".jpg";
      }
    }

    System.out.println(sImageURL);
  }

  // Pull an html page and return HTML in string
  private static String getWebPage(String sURL) {
    HttpURLConnection connection;
    int iResponse;

    try {
      URL requestURL = new URL(sURL);
      connection = (HttpURLConnection)requestURL.openConnection();
      connection.setRequestMethod("GET");
      iResponse = connection.getResponseCode();
    } catch (Exception e) {
      if (e instanceof MalformedURLException) {
        System.out.println(e.getMessage());
      } else if (e instanceof UnknownHostException) {
        System.out.println("Unknown host: "+e.getMessage());
      } else if (e instanceof ConnectException) {
        System.out.println(e.getMessage());
      } else {
        System.out.println(e);
      }
      return null;
    }

    // Non-200 response means we did something wrong
    if (iResponse != 200) {
      System.out.println("Server returned error code: "+iResponse);
      return null;
    }

    // Constructed string from HTTP stream
    StringBuffer response = new StringBuffer();

    try {
      // Download the response from the server
      InputStream stream = connection.getInputStream();
      BufferedReader in = new BufferedReader(new InputStreamReader(stream));

      String readLine;
      while ((readLine = in.readLine()) != null)
        response.append(readLine);

      in.close();
    } catch (Exception e) {
      System.out.println("Error downloading responce from server!");
    }

    return response.toString();
  }
}