Google glass GDK - 下载文件到SD卡

public static void downMusic(){
try {
URL downUrl = new URL("http://文件地址");
HttpURLConnection conn = (HttpURLConnection) downUrl.openConnection();
InputStream istream = conn.getInputStream();
String file_name = "/sdcard/保存文件名";
File file = new File(file_name);
if(!file.exists()){
file.createNewFile();
OutputStream output = new FileOutputStream(file);
byte[] buffer = new byte[1024 * 4];
while(istream.read(buffer) != -1){
output.write(buffer);
}
output.flush();
output.close();
istream.close();
}
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

new Thread(new Runnable(){
//你懂的
}).start();