网络图片获取并转换为Base64字符串

    public static String getURLImage(String imageUrl) {
        String base64String = "";
        try {
            //new一个URL对象
            URL url = new URL(imageUrl);
            //打开链接
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            //设置请求方式为"GET"
            conn.setRequestMethod("GET");
            //超时响应时间为5秒
            conn.setConnectTimeout(5 * 1000);
            //通过输入流获取图片数据
            InputStream inStream = conn.getInputStream();
            //得到图片的二进制数据，以二进制封装得到数据，具有通用性
            byte[] data = readInputStream(inStream);
            BASE64Encoder encode = new BASE64Encoder();
            base64String = "data:image/jpeg;base64," + encode.encode(data);
            //base64String = encode.encodeBuffer(data);
            Log.e("tag===",base64String);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return base64String;
    }

    private static byte[] readInputStream(InputStream inStream) throws Exception {
        ByteArrayOutputStream outStream = new ByteArrayOutputStream();
        //创建一个Buffer字符串
        byte[] buffer = new byte[1024];
        //每次读取的字符串长度，如果为-1，代表全部读取完毕
        int len = 0;
        //使用一个输入流从buffer里把数据读取出来
        while ((len = inStream.read(buffer)) != -1) {
            //用输出流往buffer里写入数据，中间参数代表从哪个位置开始读，len代表读取的长度
            outStream.write(buffer, 0, len);
        }
        //关闭输入流
        inStream.close();
        //把outStream里的数据写入内存
        return outStream.toByteArray();
    }