java HttpURLConnection下載伺服器上的檔案

String str="http://127.0.0.1:8080/httpFile/test.txt";
System.out.println("urlstr---->"+str);
try {
URL url = new URL(str);
HttpURLConnection connection = (HttpURLConnection)url.openConnection();
connection.setRequestMethod("POST");
connection.setRequestProperty("Charset","UTF-8");
connection.connect();
int file_leng = connection.getContentLength();
System.out.println("file length---->"+file_leng);
BufferedInputStream bin = new BufferedInputStream(connection.getInputStream());
String path=Environment.getExternalStorageDirectory()+"/eBook/inw/"+bookName+".inw";
File file = new File(path);
if(!file.getParentFile().exists()){
file.getParentFile().mkdirs();
}
OutputStream out=new FileOutputStream(file);
int size=0;
int len=0;
byte[] buf = new byte[1024];
while((size=bin.read(buf))!=-1){
len+=size;

out.write(buf,0,1024);

/* android 中為了更新進度條

Message msg = handler.obtainMessage();
msg.arg1=len*100/file_leng;

handler.sendMessage(msg);

*/

Thread.sleep(1000);
System.out.println("下載了： "+len*100/file_leng+"%\n");
}
bin.close();
out.close();
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}