base64图像回到png使用java太长的常量

Question

I am trying to learn java base64 conversion to image

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import redis.clients.jedis.Jedis;

public class HelloWorld {

    public static void main(String[] args) throws IOException {

        byte[] btDataFile = new sun.misc.BASE64Decoder().decodeBuffer("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAn4AAAMUCAYAAAAiyCroAAAMGWlDQ1BJQ0MgUHJvZmlsZQAASImVVwdUU0kXnldSCEkogQhICb0J0qv0XgSkg42QBAglhkBQsSOLCq4FFVEUFV0Rsa0FkLUgo...AAABJRU5ErkJggg==");
        File of = new File("/Users/myfolder/Desktop/yourFile.png");
        FileOutputStream osf = new FileOutputStream(of);
        osf.write(btDataFile);
        osf.flush();



    }
}

Problem is that it too long (which it is :) ) of a constant. Now what can I do to achieve this goal? Thanks

Answer 1

The short answer is that you shouldn't have such a long String as a constant in your source code. How to change it depends on your actual scenario:

• If you're just learning base64, use a shorter string. It will achieve the same learning effect.
• If this is just a compiler implementation limit issue (ie the problem is a String constant limit, and not a RAM memory limit), put the text into a file and load it at run time. Alternatively, if you really insist on the text being embedded in the source code, split the String into several constant-sized chunks and join them at run time.
• If the base64-encoding of the image is really too big for the amount of RAM memory your process has available, use a streaming method (I've not worked with the sun.misc package, but a quick glance at http://www.docjar.com/docs/api/sun/misc/BASE64Decoder.html shows decodeAtom and decodeBufferToByteBuffer methods which seem quite promising.