Encode a file to base64 binary in Java

EncodeBased64Binary.java

import org.apache.commons.codec.binary.Base64;


	private String encodeFileToBase64Binary(String fileName)
			throws IOException {

		File file = new File(fileName);
		byte[] bytes = loadFile(file);
		byte[] encoded = Base64.encodeBase64(bytes);
		String encodedString = new String(encoded);

		return encodedString;
	}

	private static byte[] loadFile(File file) throws IOException {
	    InputStream is = new FileInputStream(file);

	    long length = file.length();
	    if (length > Integer.MAX_VALUE) {
	        // File is too large
	    }
	    byte[] bytes = new byte[(int)length];
	    
	    int offset = 0;
	    int numRead = 0;
	    while (offset < bytes.length
	           && (numRead=is.read(bytes, offset, bytes.length-offset)) >= 0) {
	        offset += numRead;
	    }

	    if (offset < bytes.length) {
	        throw new IOException("Could not completely read file "+file.getName());
	    }

	    is.close();
	    return bytes;
	}

That solution didn't work.

Base64.encodeBase64(bytes).toString() outputs [B@c163956

Here you are a minimal working implementation

        File originalFile = new File("signature.jpg");
        String encodedBase64 = null;
        try {
            FileInputStream fileInputStreamReader = new FileInputStream(originalFile);
            byte[] bytes = new byte[(int)originalFile.length()];
            fileInputStreamReader.read(bytes);
            encodedBase64 = new String(Base64.encodeBase64(bytes));
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

Problem solved. Gave file name with location .
String attachment_string= encodeFileToBase64Binary("C:\file_location"+fileName);

Thanks albfan

It doesn't mark error if I add this library to my project: https://commons.apache.org/proper/commons-codec/ I haven't tested yet.

Hi,

I have an HTTP API which returns zip file contents as response which i have encoded in base 64 and passing it to my UI layer written in javascript.
But when I decode the contents using atob functoin in javascript, the contents of zip file is corrupted.

Please help me in solving this problem.

Mine based on @albfan code:

private String encodeFileToBase64Binary(String filePath) { File originalFile = new File(filePath); String encodedBase64; try { FileInputStream fileInputStreamReader = new FileInputStream(originalFile); byte[] bytes = new byte[(int)originalFile.length()]; int numBytesRead = fileInputStreamReader.read(bytes); if (numBytesRead != -1) { // Log.d(TAG, "encodeFileToBase64Binary: could not read all the file"); return null; } encodedBase64 = android.util.Base64.encodeToString(bytes, DEFAULT); return encodedBase64; } catch (IOException e) { e.printStackTrace(); return null; } }

@LightMan pls check your numBytesRead if condition. You're returning null if some bytes read

@albfan, Hi, I am trying this but getting exception,

java.io.FileNotFoundException: android.content.res.AssetManager$AssetInputStream@197e3549: open failed: ENOENT (No such file or directory)

val file = File(Uri.parse(resources.openRawResource(R.raw.rec1).toString()).toString())
        var encodedBase64: String? = null
        try {
            val fileInputStreamReader = FileInputStream(file)
            val bytes = ByteArray(file.length().toInt())
            fileInputStreamReader.read(bytes)
            val result = Base64.encodeToString(bytes, Base64.DEFAULT)

            println("result--" + result)
        } catch (e: FileNotFoundException) {
            e.printStackTrace()
        } catch (e: IOException) {
            e.printStackTrace()
        }

A single line solution

byte[] bytes = Base64.getEncoder().encode(Files.readAllBytes(new File("filePath").toPath()));
System.out.print(bytes);

This is working like a charm, i am not converting image to string i just needed it in encoded format.....Thanks

Why not use Base64.encodeBase64String(bytes)?

Guys cmon this was posted 10 years ago...