class - How do I Execute Java from Java? -

i have downloadfile.java , downloads file should:

import java.io.*; import java.net.url;  public class downloadfile {         public static void main(string[] args) throws ioexception {         string filename = "setup.exe";             // file saved on computer         url link = new url("http://onlinebackup.elgiganten.se/software/elgiganten/setup.exe");             // file want download          // code download         inputstream in = new bufferedinputstream(link.openstream());         bytearrayoutputstream out = new bytearrayoutputstream();         byte[] buf = new byte[1024];         int n = 0;         while (-1 != (n = in.read(buf))) {             out.write(buf, 0, n);         }         out.close();         in.close();         byte[] response = out.tobytearray();          fileoutputstream fos = new fileoutputstream(filename);         fos.write(response);         fos.close();         // end download code          system.out.println("finished");     } } 

i want execute mouse event in gui.java.

private void jlabel17mouseclicked(java.awt.event.mouseevent evt){  }    

how do this?

your current method static method, fine, data extracts held tightly within main method, preventing other classes using it, fortunately can corrected.

my suggestion:

• re-write downloadfile code not static main method, rather method can called other classes easily, , returns data file of interest. way outside classes can call method , receive data method extracted.
• give string parameter allow calling code pass in url address.
• give file parameter file should write data to.
• consider having return data (a byte array?), if data needed calling program.
• or if not need return data, perhaps return boolean indicate if download successful or not.
• make sure method throws exceptions (such io , url excptions) needs throw.
• also, if called swing gui, sure call type of code in background thread, such in swingworker, code not tie swing event thread, rendering gui frozen time.