java上传图片，压缩、更改尺寸等导致变色（表层蒙上一层红色）

表层蒙上一层红色）"/>

java上传图片，压缩、更改尺寸等导致变色（表层蒙上一层红色）

    做项目的时候遇到要对图片尺寸做处理，结果就会导致上传的图片会蒙上一层红色，代码如下

public void updateFileSize(String filePath) throws Exception {// 读取图片BufferedInputStream in = new BufferedInputStream(new FileInputStream(filePath));// 字节流转图片对象Image bi = ImageIO.read(in);// 获取图像的高度，宽度int height = bi.getHeight(null);int width = bi.getWidth(null);int toHeight = GlobalConstant.BASE_FILE_SIZE_NORMAl;int toWidth = GlobalConstant.BASE_FILE_SIZE_NORMAl;if (toHeight != height && toWidth != width) {// 构建图片流BufferedImage tag = new BufferedImage(toWidth, toHeight, BufferedImage.TYPE_INT_RGB);// 绘制改变尺寸后的图tag.getGraphics().drawImage(bi, 0, 0, toWidth, toHeight, null);// 输出流String imageType = getFormatName(new File(filePath));BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(filePath));ImageIO.write(tag, imageType, out);in.close();out.close();}}

原图

处理后的图

浪费了很多时间，换各种处理图片的方法都没找到问题，才发现只要使用ImageIO.read(in)读取图片可能就会导致变色。可通过BufferedImage读取图片，即可解决问题。代码如下：

Image src = Toolkit.getDefaultToolkit().getImage(filePath);
BufferedImage image = this.toBufferedImage(src);// Image to BufferedImage

public BufferedImage toBufferedImage(Image image) {if (image instanceof BufferedImage) {return (BufferedImage) image;}// This code ensures that all the pixels in the image are loadedimage = new ImageIcon(image).getImage();BufferedImage bimage = null;GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();try {int transparency = Transparency.OPAQUE;GraphicsDevice gs = ge.getDefaultScreenDevice();GraphicsConfiguration gc = gs.getDefaultConfiguration();bimage = gc.createCompatibleImage(image.getWidth(null), image.getHeight(null), transparency);} catch (HeadlessException e) {// The system does not have a screen}if (bimage == null) {// Create a buffered image using the default color modelint type = BufferedImage.TYPE_INT_RGB;bimage = new BufferedImage(image.getWidth(null), image.getHeight(null), type);}// Copy image to buffered imageGraphics g = bimage.createGraphics();// Paint the image onto the buffered imageg.drawImage(image, 0, 0, null);g.dispose();return bimage;}