java上传文件

/* 上传文件至Server的方法 */
	private void uploadFile() {
		String end = "\r\n";
		String twoHyphens = "--";
		String boundary = "*****";
		try {
			String params = "m=avatars";
			URL url = new URL(actionUrl);
			HttpURLConnection con = (HttpURLConnection) url.openConnection();
//			setCookies
			con.setRequestProperty("Cookie",
					"Doer_uid=20;Doer_pwd=748649c7d2bc06dbea2bbf7e9e9ad5f4");
			/* 允许Input、Output，不使用Cache */
			con.setDoInput(true);
			con.setDoOutput(true);
			con.setUseCaches(false);
			/* 设置传送的method=POST */
			con.setRequestMethod("POST");
			/* setRequestProperty */
			con.setRequestProperty("Connection", "Keep-Alive");
			con.setRequestProperty("Charset", "UTF-8");
			con.setRequestProperty("Content-Type",
					"multipart/form-data;boundary=" + boundary);
			con.connect();
			/* 设置DataOutputStream */
			DataOutputStream ds = new DataOutputStream(con.getOutputStream());
			//写入其他参数
			ds.writeBytes(params);
			ds.writeBytes(twoHyphens + boundary + end);
			//name=服务器接受的文件的key
			ds.writeBytes("Content-Disposition: form-data; "
					+ "name=\"upload_file\";filename=\"" + newName + "\"" + end);
			ds.writeBytes(end);
			/* 取得文件的FileInputStream */
			FileInputStream fStream = new FileInputStream(uploadFile);
			/* 设置每次写入1024bytes */
			int bufferSize = 1024;
			byte[] buffer = new byte[bufferSize];
			int length = -1;
			/* 从文件读取数据至缓冲区 */
			while ((length = fStream.read(buffer)) != -1) {
				/* 将资料写入DataOutputStream中 */
				ds.write(buffer, 0, length);
			}
			ds.writeBytes(end);
			ds.writeBytes(twoHyphens + boundary + twoHyphens + end);
			/* close streams */
			fStream.close();
			ds.flush();
			/* 取得Response内容 */
			InputStream is = con.getInputStream();
			int ch;
			StringBuffer b = new StringBuffer();
			while ((ch = is.read()) != -1) {
				b.append((char) ch);
			}
			/* 将Response显示于Dialog */
//			showDialog("上传成功" + b.toString().trim());
			System.out.println("---------------" + b.toString().trim());
			/* 关闭DataOutputStream */
			ds.close();
		} catch (Exception e) {
//			showDialog("上传失败" + e);
			e.printStackTrace();
		}
	}