java ImageIO.write图片上传变色及背景变黑解决

java ImageIO.write图片上传变色及背景变黑解决

public void getImage(HttpServletRequest request, HttpServletResponse response) throws Exception { response.setDateHeader("Expires", 0); response.setHeader("Cache-Control", "no-store, no-cache, must-revalidate"); response.addHeader("Cache-Control", "post-check=0, pre-check=0"); response.setHeader("Pragma", "no-cache"); response.setContentType("image/jpeg"); String uri = request.getRequestURI(); String imgPath = uri.replace("/ofc/rest/img", ""); File image = new File(imgPath); BufferedImage bi = ImageIO.read(image); BufferedImage newBi = resizeImagePng(bi.getWidth(), bi.getHeight(),bi); Graphics2D g2d = newBi.createGraphics(); g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, 1.0f)); ServletOutputStream out = response.getOutputStream(); g2d.drawImage(newBi,0,0,null); ImageIO.write(newBi,"png", out); //ImageIO.write(bi, "jpg", out); //saveAs(bi,"jpg", out); } public static BufferedImage resizeImagePng(int x, int y, BufferedImage bfi) { BufferedImage bufferedImage = new BufferedImage(x, y, BufferedImage.TYPE_INT_ARGB); bufferedImage.getGraphics().drawImage( bfi.getScaledInstance(x, y, Image.SCALE_SMOOTH), 0, 0, null); return bufferedImage; } public static void saveAs(BufferedImage image, String formatName, ServletOutputStream outFile) throws IOException { if (formatName.equalsIgnoreCase("jpg") || formatName.equalsIgnoreCase("jpeg")) { BufferedImage tag = new BufferedImage(image.getWidth(), image.getHeight(), BufferedImage.TYPE_INT_BGR); Graphics g = tag.getGraphics(); // Graphics2D gg=tag.createGraphics(); // tag = gg.getDeviceConfiguration().createCompatibleImage(image.getWidth(), image.getHeight(),Transparency.TRANSLUCENT); // gg.dispose(); // gg = tag.createGraphics(); // gg.drawImage(image, 0, 0,null); g.drawImage(image, 0, 0,image.getWidth(), image.getHeight(),image.getGraphics().getColor(), null); // 绘制缩小后的图 g.dispose(); image = tag; } ImageIO.write(image, formatName, outFile); }