验证码图片生成及无法显示问题的解决

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;

public final class ImageUtil {
    
    private static final char[] chars = { ‘0‘,‘1‘,‘2‘,‘3‘,‘4‘,‘5‘,‘6‘,‘7‘,‘8‘,‘9‘,‘A‘,‘B‘,‘C‘,‘D‘,‘E‘,‘F‘,‘G‘,‘H‘,‘I‘ };
    private static final int SIZE = 4;
    private static final int LINES = 5;
    private static final int WIDTH = 80;
    private static final int HEIGHT = 40;
    private static final int FONT_SIZE = 30;

    public static Map<String,BufferedImage> createImage() {
        StringBuffer sb = new StringBuffer();
        BufferedImage image = new BufferedImage(WIDTH,HEIGHT,BufferedImage.TYPE_INT_RGB);
        Graphics graphic = image.getGraphics();
        graphic.setColor(Color.LIGHT_GRAY);
        graphic.fillRect(0,0,WIDTH,HEIGHT);
        Random ran = new Random();
        
        for (int i = 1; i <= SIZE; i++) {
            int r = ran.nextInt(chars.length);
            graphic.setColor(getRandomColor());
            graphic.setFont(new Font(null,Font.BOLD + Font.ITALIC,FONT_SIZE));
            graphic.drawString(chars[r] + "",(i - 1) * WIDTH / SIZE,HEIGHT / 2);
            sb.append(chars[r]);
        }
        
        for (int i = 1; i <= LINES; i++) {
            graphic.setColor(getRandomColor());
            graphic.drawLine(ran.nextInt(WIDTH),ran.nextInt(HEIGHT),ran.nextInt(WIDTH),ran.nextInt(HEIGHT));
        }
        Map<String,BufferedImage> map = new HashMap<String,BufferedImage>();
        map.put(sb.toString(),image);
        return map;
    }

    public static Color getRandomColor() {
        Random ran = new Random();
        Color color = new Color(ran.nextInt(256),ran.nextInt(256),ran.nextInt(256));
        return color;
    }

    public static InputStream getInputStream(BufferedImage image)
            throws IOException {
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(bos);
        encoder.encode(image);
        byte[] imageBts = bos.toByteArray();
        InputStream in = new ByteArrayInputStream(imageBts);
        return in;
    }

}