java - 如何将Uri图片转成Base64？

Question

我已经编写代码将图像从文件位置转换为 base64。我可以轻松地将图像从绝对文件位置转换为 base64，例如:C:/Users/Java Engineer/Desktop/test/gallery/magar/Kanuglam.jpg，但我无法从像
.我想从网络服务转换图像以在 android 中使用。 这是代码示例:

/**
 * TEST JSON
 */
String convertToJsonArrayWithImageForMovieDetailTest(ResultSet rs) {

    System.out.println("I am insied json converter");
    JSONArray list = new JSONArray();
    JSONObject obj ;

    //File file;
    File locatedFile;
    FileInputStream fileInputStream;
    try {

        while (rs.next()) {
            obj = new JSONObject();
            System.out.println("inside RS");
            System.out.println("date is there ha ha ");

            obj.put("movie_name", rs.getString("name"));
            obj.put("movie_gener", rs.getString("type"));
            String is_free_stuff = rs.getString("is_free_stuff");
            if (is_free_stuff == "no") {
                is_free_stuff = "PAID";
            } else {
                is_free_stuff = "FREE";
            }
            obj.put("movie_type", is_free_stuff);

            //String movie_image = rs.getString("preview_image");

            //this does not work
            String movie_image = "http://www.hamropan.com/stores/slider/2016-09-10-852311027.jpg";

            //this works for me
        //  file = new File("C:/Users/Java Engineer/Desktop/Nike Zoom Basketball.jpg");
            locatedFile = new File(movie_image);
            // Reading a Image file from file system
            fileInputStream = new FileInputStream(locatedFile);
            if (locatedFile == null) {
                obj.put("movie_image", "NULL");
            } else {
                byte[] iarray = new byte[(int) locatedFile.length()];
                fileInputStream.read(iarray);
                byte[] img64 = com.sun.jersey.core.util.Base64
                        .encode(iarray);
                String imageString = new String(img64);
                obj.put("movie_image", imageString);
            }
            list.add(obj);
        }


    } catch (Exception e) {
        e.printStackTrace();
    }
    return list.toString();
}

这段代码对我有用，但它看起来很慢

public String imageConvertMethod(String url) throws Exception{
    ByteArrayOutputStream output = new ByteArrayOutputStream();

    try (InputStream input = new URL(url).openStream()) {
        byte[] buffer = new byte[512];
        for (int length = 0; (length = input.read(buffer)) > 0;) {
             output.write(buffer, 0, length);
        }
    }

    byte [] byte_array = output.toByteArray();

    byte[] img64 = com.sun.jersey.core.util.Base64
            .encode(byte_array);
    String  imageString = new String(img64);

    return imageString;
}

Answer 1

好的，试试这个

bitmap = getBitmapFromUrl(image_url);
ByteArrayOutputStream stream = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream);

byte[] array = stream.getByteArray();
encoded_string = Base64.encodeToString(array, 0);

从url加载图片的方法

public static Bitmap getBitmapFromURL(String src) {
  try {
      URL url = new URL(src);
      HttpURLConnection connection = (HttpURLConnection) url.openConnection();
      connection.setDoInput(true);
      connection.connect();
      InputStream input = connection.getInputStream();
      Bitmap myBitmap = BitmapFactory.decodeStream(input);
      return myBitmap;
  } catch (IOException e) {
     e.printStackTrace();
     return null;
  }
}