How correct send encoded base64 image to nodeJS and get response in Java

Question

I would like using HttpClient to invoke a service (localhost/png/ 'imageWithBase64') which will return me answer from the variable 'result'. Ocrad.js reads a basic, simple text with images.

I have 3 questions: - How to send Java is base64 encoded to the service? - And whether paste this id to img.src will work correctly? - The result returned with the form of JSON or HTML format?

Currently, I get a bug in Java (I can not send the entire String as a parameter id to the service)

java.lang.IllegalArgumentException: Illegal character in path

Code Java:

        File file = new File(getClass().getClassLoader().getResource("test.png").getFile());

        String encodedFile = Base64.encode(FileUtils.readFileToByteArray(file));

        String url = "http://127.0.0.1:3000/png/"+encodedFile;

        HttpClient client = HttpClientBuilder.create().build();
        HttpGet request = new HttpGet(url);

        HttpResponse response = client.execute(request);

        BufferedReader rd = new BufferedReader(
                new InputStreamReader(response.getEntity().getContent()));

        StringBuffer result = new StringBuffer();
        String line;
        while ((line = rd.readLine()) != null) {
            result.append(line);
        }

        System.out.println(result.toString());

My Java Dependency:

 <dependencies>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.4.1</version>
        </dependency>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-io</artifactId>
            <version>1.3.2</version>
        </dependency>
    </dependencies>

And server with nodeJS:

var express = require('express');
var OCRAD = require('ocrad.js');
var Canvas = require('canvas');
var Image = Canvas.Image;

var app = express();

app.get('/png/:id', function(req, res) {

var img = new Image();
img.src = 'data:image/png;base64,'+req.params.id; 
var canvas = new Canvas(img.width, img.height);
var ctx = canvas.getContext('2d');
ctx.drawImage(img, 0, 0, img.width, img.height);
var result = OCRAD(canvas);
res.send({result:result});
});

app.listen(3000);
console.log('Listening on port 3000...');