java根据扩展名获取系统图标和文件图标示例

import java.io.file;
import java.io.ioexception;
import java.awt.borderlayout;
import java.awt.event.actionevent;
import java.awt.event.actionlistener;
import javax.swing.icon;
import javax.swing.imageicon;
import javax.swing.jbutton;
import javax.swing.jframe;
import javax.swing.jpanel;
import javax.swing.jtextfield;
import javax.swing.jlabel;
import javax.swing.boxlayout;
import javax.swing.filechooser.filesystemview;
import sun.awt.shell.shellfolder;

public class fileiconextractor extends jframe implements actionlistener{
private jbutton geticonbtn = new jbutton("get icon");
private jpanel iconpanel = new jpanel();
private jtextfield extfield = new jtextfield();
private jlabel smalliconlabel = new jlabel("small icon here");
private jlabel bigiconlabel = new jlabel("big icon here");

public fileiconextractor() {
this.setsize(200, 150);
this.setdefaultcloseoperation(jframe.exit_on_close);
this.setlayout(new borderlayout());
geticonbtn.setactioncommand("geticon");
geticonbtn.addactionlistener(this);
iconpanel.setlayout(new boxlayout(iconpanel, boxlayout.y_axis));
iconpanel.add(smalliconlabel);
iconpanel.add(bigiconlabel);
this.add(extfield, borderlayout.north);
this.add(iconpanel, borderlayout.center);
this.add(geticonbtn, borderlayout.south);
this.setvisible(true);
}

public void actionperformed(actionevent e) {
if (e.getactioncommand().equals("geticon")) {
string ext = extfield.gettext();
file file;
try
{
      file = file.createtempfile("icon", "." + ext);
      filesystemview view = filesystemview.getfilesystemview();
      icon smallicon = view.getsystemicon(file);
      shellfolder shellfolder = shellfolder.getshellfolder(file);
      icon bigicon = new imageicon(shellfolder.geticon(true));
      seticonlabel(smallicon, bigicon);
      file.delete();
}
catch (ioexception ioe)
{
ioe.printstacktrace();
}
}
}

private void seticonlabel(icon smallicon, icon bigicon) {
smalliconlabel.seticon(smallicon);
bigiconlabel.seticon(bigicon);
}

public static void main(string[] args) {
fileiconextractor fie = new fileiconextractor();
}
}