Java如何下载图片到本地

	/**
	* 根据url下载图片到本地
	* @param imgUrl 图片的路径
	*/
	private void saveImg(String imgUrl) {
		try {
			//建立URL连接
			URL url = new URL(imgUrl);
			HttpURLConnection conn = (HttpURLConnection) url.openConnection();
			conn.setRequestMethod("GET");
			conn.setConnectTimeout(2 * 1000);
			InputStream inStream = conn.getInputStream();
			byte[] data = readInputStream(inStream);
			String path = getImgPath(imgUrl);
			File result = new File(PTAH_PREFIX + path);
			if (!result.exists()) {
				result.mkdirs();
			}
			String fileName = getImgFileName(imgUrl);
			FileOutputStream outStream = new FileOutputStream(result + File.separator + fileName);
			outStream.write(data);
			outStream.flush();
			outStream.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	private static byte[] readInputStream(InputStream inStream) throws Exception {
		ByteArrayOutputStream outStream = new ByteArrayOutputStream();
		byte[] buffer = new byte[1024];
		int len = 0;
		while ((len = inStream.read(buffer)) != -1) {
			outStream.write(buffer, 0, len);
		}
		inStream.close();
		// 把outStream里的数据写入内存
		return outStream.toByteArray();
	}

	/**
	* 根据url获取图片的路径
	*/
	private String getImgPath(String imgUrl) {
		return imgUrl.substring(imgUrl.indexOf("n/") + 1, imgUrl.lastIndexOf("/"));
	}
	
	/**
	* 根据url获取图片的名称
	*/
	private String getImgFileName(String imgUrl) {
		return imgUrl.substring(imgUrl.lastIndexOf("/") + 1);
	}