生成缩略图(如验证码) 博客分类: java编程 缩略图验证码
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2024-03-25 15:01:10
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import java.awt.Color; import java.awt.Graphics2D; import java.awt.Image; import java.awt.RenderingHints; import java.awt.image.BufferedImage; import java.io.File; public class ThumbnailGenerator { public void transform(String originalFile, String thumbnailFile, int thumbWidth, int thumbHeight, int quality) throws Exception { Image image = javax.imageio.ImageIO.read(new File(originalFile)); 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); } if(imageWidth < thumbWidth && imageHeight < thumbHeight) { thumbWidth = imageWidth; thumbHeight = imageHeight; } else if(imageWidth < thumbWidth) thumbWidth = imageWidth; else if(imageHeight < thumbHeight) thumbHeight = imageHeight; BufferedImage thumbImage = new BufferedImage(thumbWidth, thumbHeight, BufferedImage.TYPE_INT_RGB); Graphics2D graphics2D = thumbImage.createGraphics(); graphics2D.setBackground(Color.WHITE); graphics2D.setPaint(Color.WHITE); graphics2D.fillRect(0, 0, thumbWidth, thumbHeight); graphics2D.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR); graphics2D.drawImage(image, 0, 0, thumbWidth, thumbHeight, null); javax.imageio.ImageIO.write(thumbImage, "JPG", new File(thumbnailFile)); } }