Java Convert Image to Base64 String and Base64 to Image

In this post, we will be converting an image to base64 string so that it can be save to a database, more accurately in a blob type column.

Encode Image to Base64 String

The below method will encode the Image to Base64 String. The result will be a String consisting of random characters, representing the image. This characters can then be save to the database. A blob type column is more applicable when saving an image to the database since a blob column can hold large amount of data.

public static String encodeToString(BufferedImage image, String type) {
        String imageString = null;
        ByteArrayOutputStream bos = new ByteArrayOutputStream();

        try {
            ImageIO.write(image, type, bos);
            byte[] imageBytes = bos.toByteArray();

            BASE64Encoder encoder = new BASE64Encoder();
            imageString = encoder.encode(imageBytes);

        } catch (IOException e) {
        return imageString;

Decode Base64 String to Image

Meanwhile, you can also decode your base64 string to an image to be save or sent to the client. Below is a method on how to decode base64 string to image.

public static BufferedImage decodeToImage(String imageString) {

        BufferedImage image = null;
        byte[] imageByte;
        try {
            BASE64Decoder decoder = new BASE64Decoder();
            imageByte = decoder.decodeBuffer(imageString);
            ByteArrayInputStream bis = new ByteArrayInputStream(imageByte);
            image =;
        } catch (Exception e) {
        return image;

For example, if the data/string came from a client request, if the base64 string starts with something like data:image/png;base64,iVBORw0KGgoAA….. you should remove data:image/png;base64, . Therefore, your base64 string should starts with eg. iVBORw0KGgoAA.

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