Android Bitmap与Base64相互转化工具类

public class Base64BitmapUtil {
    /**
     * bitmap转为base64
     *
     * @param bitmap
     * @return
     */
    public static String bitmapToBase64(Bitmap bitmap) {

        String result = null;
        ByteArrayOutputStream baos = null;
        try {
            if (bitmap != null) {
                baos = new ByteArrayOutputStream();
                bitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);

                baos.flush();
                baos.close();

                byte[] bitmapBytes = baos.toByteArray();
                result = Base64.encodeToString(bitmapBytes, Base64.DEFAULT);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (baos != null) {
                    baos.flush();
                    baos.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return result;
    }

    /**
     * base64转为bitmap
     *
     * @param base64Data
     * @return
     */
    public static Bitmap base64ToBitmap(String base64Data) {
        byte[] bytes = Base64.decode(base64Data, Base64.DEFAULT);
        return BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
    }
    /**
     * 压缩图片（质量压缩）
     * @param bitmap
     */
    public static File compressImage(Bitmap bitmap) {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        bitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);//质量压缩方法，这里100表示不压缩，把压缩后的数据存放到baos中
        int options = 100;
        while (baos.toByteArray().length / 1024 > 500) {  //循环判断如果压缩后图片是否大于500kb,大于继续压缩
            baos.reset();//重置baos即清空baos
            options -= 10;//每次都减少10
            bitmap.compress(Bitmap.CompressFormat.JPEG, options, baos);//这里压缩options%，把压缩后的数据存放到baos中
            long length = baos.toByteArray().length;
        }
        SimpleDateFormat format = new SimpleDateFormat("yyyyMMddHHmmss");
        Date date = new Date(System.currentTimeMillis());
        String filename = format.format(date);
        File file = new File(Environment.getExternalStorageDirectory(),filename+".png");
        try {
            FileOutputStream fos = new FileOutputStream(file);
            try {
                fos.write(baos.toByteArray());
                fos.flush();
                fos.close();
            } catch (IOException e) {
                Log.e("tag1",e.getMessage());
                e.printStackTrace();
            }
        } catch (FileNotFoundException e) {
            Log.e("tag",e.getMessage());
            e.printStackTrace();
        }
        recycleBitmap(bitmap);
        return file;
    }
    public static void recycleBitmap(Bitmap... bitmaps) {
        if (bitmaps==null) {
            return;
        }
        for (Bitmap bm : bitmaps) {
            if (null != bm && !bm.isRecycled()) {
                bm.recycle();
            }
        }
    }
    public static InputStream bitmapToIS(Bitmap bm) {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        bm.compress(Bitmap.CompressFormat.PNG, 100, baos);
        InputStream isBm = new ByteArrayInputStream(baos.toByteArray());
        return isBm;
    }

}