Java BufferedImage相关使用介绍及示例代码

1､获得BufferedImage对象

File file = new File（”001.jpg“）;//本地图片BufferedImage image=(BufferedImage)ImageIO.read(file);URL url= new URL（”http://*******“）;//通过图片urlBufferedImage image=(BufferedImage)ImageIO.read(url);

2､创建BufferedImage对象

private static BufferedImage createBufferedImage(final boolean  aa) {
    final BufferedImage bi = new BufferedImage(SIZE, SIZE,
                                               BufferedImage.TYPE_INT_RGB);
    final Graphics2D bg = bi.createGraphics();
    bg.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                        aa ? RenderingHints.VALUE_ANTIALIAS_ON
                           : RenderingHints.VALUE_ANTIALIAS_OFF);
    bg.setColor(Color.RED);
    bg.fillRect(0, 0, SIZE, SIZE);
    bg.translate(100, 100);
    bg.rotate(Math.toRadians(90));
    bg.setColor(Color.BLACK);
    bg.setFont(bg.getFont().deriveFont(20.0f));
    bg.drawString("MMMMMMMMMMMMMMMM", 0, 0);
    bg.dispose();
    return bi;
}

private static BufferedImage createImage(int scale) throws Exception {
    BufferedImage image = new BufferedImage(scale * 200, scale * 300,
                                            BufferedImage.TYPE_INT_RGB);
    Graphics g = image.createGraphics();
    g.setColor(scale == 1 ? COLOR_1X : COLOR_2X);
    g.fillRect(0, 0, scale * 200, scale * 300);
    g.dispose();
    return image;
}

3､获取图片的每个像素点的像素值

private static HashSet getAntialiasedColors(Object aaHint, int lcdContrast) {        JLabel label = new JLabel("ABCD");        label.setSize(label.getPreferredSize());        label.putClientProperty(KEY_TEXT_ANTIALIASING, aaHint);        label.putClientProperty(KEY_TEXT_LCD_CONTRAST, lcdContrast);        int w = label.getWidth();        int h = label.getHeight();        BufferedImage buffImage = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);        Graphics2D g = buffImage.createGraphics();        g.setColor(Color.WHITE);        g.fillRect(0, 0, w, h);        label.paint(g);        g.dispose();        HashSet colors = new HashSet<>();        for (int i = 0; i < w; i++) {            for (int j = 0; j < h; j++) {                Color color = new Color(buffImage.getRGB(i, j));                colors.add(color);            }        }        return colors;    }

4､压缩图片

/** * @param is * @param deistPath * @param newWidth * @param newHeight * @return int * @Title: saveCompress * @Description: 压缩图片，统一压缩成JPG格式，返回压缩后的大小（字节） */public static int saveCompress(InputStream is, String deistPath,                               int newWidth, int newHeight) {    try {        BufferedImage srcImage = ImageIO.read(is);        BufferedImage destImage = resize(srcImage, newWidth, newHeight);        File deistFile = new File(deistPath);        String fileName = deistFile.getName();        String formatName = fileName                .substring(fileName.lastIndexOf('.') + 1);        ImageIO.write(destImage, formatName, deistFile);        return (int) deistFile.length();    } catch (Exception e) {        return -1;    }}

5､比较两个BufferedImage图片

/** * Compares two images. */private static void compareImage(final BufferedImage bi1,                                 final BufferedImage bi2)        throws IOException {    for (int i = 0; i < SIZE; ++i) {        for (int j = 0; j < SIZE; ++j) {            if (bi1.getRGB(i, j) != bi2.getRGB(i, j)) {                ImageIO.write(bi1, "png", new File("image1.png"));                ImageIO.write(bi2, "png", new File("image2.png"));                throw new RuntimeException("Failed: wrong text location");            }        }    }}