How to convert byte array to base64 String

Question

List<Map<String, Object>> lists = baseDao.getJdbcTemplate().queryForList(queryForImages, productId);
        **System.out.println("size----" + lists.size());**
        ArrayList<String> arrayList = new ArrayList<String>();
        for (Map<String, Object> base64 : lists) {
            byte[] imgData = (byte[]) base64.get("images");
            String base64Encoded = new String(imgData, StandardCharsets.UTF_8);
            // byte[] encodedImage = Base64.encodeBase64(imgData);
            System.out.println("encoded---2" + base64Encoded);
        }

i retrieve list of images from db and convert byte array to base64 string ,if i sysout only the last image in the list prints in sysout , even sysout list.size under the method is not printing .

Another option to convert byte array to base64 string is Base64.encode(imgData ) — PVR
– PVR, Commented Jun 20, 2016 at 13:06
hello kevin , i dont get any exception , from db i get list of images ,if i sysout only the last image in the list prints ,and why sysout (lists.size()); is not printing , the only thing i get is last image gets converted to base64 , i need to all images in the list . — cool rock
– cool rock, Commented Jun 20, 2016 at 17:02

Jesper · Accepted Answer · 2016-06-20 13:09:52Z

14

To start with, this is wrong:

String base64Encoded = new String(imgData, StandardCharsets.UTF_8);

The image bytes you have do not represent UTF-8 encoded text, so it makes no sense to create a String out of the bytes, pretending that this is UTF-8 encoded text.

If you are using Java 8, then use the Base64 class available in the standard library:

import java.util.Base64;

// ...

byte[] imgData = (byte[]) base64.get("images");

String base64Encoded = Base64.getEncoder().encodeToString(imgData);

If you are not using Java 8, you can use a third-party library, for example Apache Commons Codec, which includes classes for Base64 encoding and decoding.

answered Jun 20, 2016 at 13:09

Jesper

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2 Comments

cool rock Over a year ago

i use java 1.7 , Base64.getEncoder() this method is not available in import org.apache.commons.codec.binary.Base64 please tell me what is jar needed .

cool rock Over a year ago

youtube.com/watch?v=t7g06nzlkjo , please watch this videos because still i have problem

Mohammad Badiuzzaman · Accepted Answer · 2018-12-17 16:21:51Z

13

In android, you can use Base64 (android.util.Base64) to encoded byte[] to String;

String encodedString = Base64.encodeToString(byteArray, Base64.DEFAULT);

and

Decoding part as like following;

byte[] byteArray = org.apache.commons.codec.binary.Base64.decodeBase64(encodedString);

Usually this technique used in android app to send binary file/data to Server, using Web Service;

answered Dec 17, 2018 at 16:21

Mohammad Badiuzzaman

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Comments

narko · Accepted Answer · 2017-11-02 11:41:20Z

4

If you are working with Android you can use the following code by importing the Android version of the Base64 class:

Base64.encodeToString(payload, Base64.DEFAULT);

From Android API 26, you can use java.util.Base64 as well.

answered Nov 2, 2017 at 11:41

narko

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Comments

Mike Adamenko · Accepted Answer · 2017-03-21 14:22:22Z

3

Prior to java 1.8 use apache commons library

String base64 = new String(Base64.encodeBase64(imgData))

answered Mar 21, 2017 at 14:22

Mike Adamenko

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