Java 文件生成缩略图方法一

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public static void createThumbnail(String filename, int thumbWidth,
            int thumbHeight, int quality, String outFilename)
            throws InterruptedException, FileNotFoundException, IOException {
        // load image from filename
        Image image = Toolkit.getDefaultToolkit().getImage(filename);
        MediaTracker mediaTracker = new MediaTracker(new Container());
        mediaTracker.addImage(image, 0);
        mediaTracker.waitForID(0);
        // use this to test for errors at this point:
        // System.out.println(mediaTracker.isErrorAny());
        // determine thumbnail size from WIDTH and HEIGHT
        double thumbRatio = (double) thumbWidth / (double) thumbHeight;
        int imageWidth = image.getWidth(null);
        int imageHeight = image.getHeight(null);
        double imageRatio = (double) imageWidth / (double) imageHeight;
        if (thumbRatio < imageRatio) {
            thumbHeight = (int) (thumbWidth / imageRatio);
        } else {
            thumbWidth = (int) (thumbHeight * imageRatio);
        }

        // draw original image to thumbnail image object and
        // scale it to the new size on-the-fly
        BufferedImage thumbImage = new BufferedImage(thumbWidth, thumbHeight,
                BufferedImage.TYPE_INT_RGB);
        Graphics2D graphics2D = thumbImage.createGraphics();
        graphics2D.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
                RenderingHints.VALUE_INTERPOLATION_BILINEAR);
        graphics2D.drawImage(image, 0, 0, thumbWidth, thumbHeight, null);

        // save thumbnail image to outFilename
        BufferedOutputStream out = new BufferedOutputStream(
                new FileOutputStream(outFilename));
        JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
        JPEGEncodeParam param = encoder.getDefaultJPEGEncodeParam(thumbImage);
        quality = Math.max(0, Math.min(quality, 100));
        param.setQuality((float) quality / 100.0f, false);
        encoder.setJPEGEncodeParam(param);
        encoder.encode(thumbImage);
        out.close();

    }

转载于:https://my.oschina.net/u/238082/blog/144893

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