网络读取图片

public static void main(String[] args) {
File file = new File("C:\\javalogo.gif");
OutputStream os = null;
try{
URL url = new URL("http://ef.icoupon.com.cn/admin/upload/uploadimage/2009/6/20096181424423.png");
InputStream is = url.openConnection().getInputStream();
file.createNewFile();
os = new FileOutputStream(file);
int b = is.read();
while (b != -1){
os.write(b);
b = is.read();
}
is.close();
os.close();
}catch(Exception e){
e.printStackTrace();
System.out.println(e);
}
}