以下方法弃用了，改用twelvemonkeys
<dependency>
<groupId>com.twelvemonkeys.imageio</groupId>
<artifactId>imageio-jpeg</artifactId>
<version>3.3.2</version>
</dependency>public static BufferedImage toBufferedImage(File imgFile, int maxWidth, int maxHeight){
if(imgFile.exists()){
try {
// ImageIO 支持的图片类型 : [BMP, bmp, jpg, JPG, wbmp, jpeg, png, PNG, JPEG, WBMP, GIF, gif]
String types = Arrays.toString(ImageIO.getReaderFormatNames());
String suffix = null;
// 获取图片后缀
if(imgFile.getName().indexOf(\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\".\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\") > -1) {
suffix = imgFile.getName().substring(imgFile.getName().lastIndexOf(\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\".\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\") + 1);
}// 类型和图片后缀全部小写，然后判断后缀是否合法
if(suffix == null || types.toLowerCase().indexOf(suffix.toLowerCase()) < 0){
logger.error(\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\"Sorry, the image suffix is illegal. the standard image suffix is {}.\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\" + types);
return null;
}
Image img = ImageIO.read(imgFile);
// 根据原图与要求的缩略图比例，找到最合适的缩略图比例
int width = img.getWidth(null);
int height = img.getHeight(null);
int[] wh=calcWH(width,height,maxWidth,maxHeight);
int w=wh[0];
int h=wh[1];
if(w==width && h==height){
logger.debug(\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\"宽度高度没有压缩,返回源文件!\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\");
return ImageIO.read(imgFile);
}
BufferedImage bi = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
Graphics g = bi.getGraphics();
g.drawImage(img, 0, 0, w, h, null);
g.dispose();
return bi;
} catch (IOException e) {
logger.error(\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\"generate thumbnail image failed.\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\",e);
try {
Image img ;
//Find a suitable ImageReader
java.util.Iterator readers = ImageIO.getImageReadersByFormatName(\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\"JPEG\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\");
javax.imageio.ImageReader reader = null;
while(readers.hasNext()) {
reader = (javax.imageio.ImageReader)readers.next();
if(reader.canReadRaster()) {
break;
}
}
//Stream the image file (the original CMYK image)
javax.imageio.stream.ImageInputStream input = ImageIO.createImageInputStream(imgFile);
reader.setInput(input);
//Read the image raster
java.awt.image.Raster raster = reader.readRaster(0, null);
raster.getWidth();
//Create a new RGB image
int width = raster.getWidth();
int height = raster.getHeight();
int[] wh=calcWH(width,height,maxWidth,maxHeight);
int w=wh[0];
int h=wh[1];
BufferedImage bi;
bi = createJPEG4(raster);
//bi = new BufferedImage(width, height, BufferedImage.TYPE_4BYTE_ABGR);
//Fill the new image with the old raster
//bi.getRaster().setRect(w/width, h/height,raster);
//g.drawImage(raster, 0, 0, w, h, null);
img = bi.getScaledInstance(w, h, Image.SCALE_SMOOTH);
BufferedImage bi2 = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
Graphics g = bi2.getGraphics();
g.drawImage(img, 0, 0, w, h, null);
g.dispose();
return bi2;
} catch (Exception e1) {
e1.printStackTrace();
//com.twelvemonkeys.imageio.plugins.jpeg.JPEGImageReader r = new com.twelvemonkeys.imageio.plugins.jpeg.JPEGImageReader();
}
}
}else{
logger.warn(\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\"the image is not exist.\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\");
}
return null;
}
private static BufferedImage createJPEG4(Raster raster) {
int w = raster.getWidth();
int h = raster.getHeight();
byte[] rgb = new byte[w * h * 3];
// 彩色空间转换
float[] Y = raster.getSamples(0, 0, w, h, 0, (float[]) null);
float[] Cb = raster.getSamples(0, 0, w, h, 1, (float[]) null);
float[] Cr = raster.getSamples(0, 0, w, h, 2, (float[]) null);
float[] K = raster.getSamples(0, 0, w, h, 3, (float[]) null);
for (int i = 0, imax = Y.length, base = 0; i < imax; i++, base += 3) {
float k = 220 - K[i], y = 255 - Y[i], cb = 255 - Cb[i], cr = 255 - Cr[i];
double val = y + 1.402 * (cr - 128) - k;
val = (val - 128) * .65f + 128;
rgb[base] = val < 0.0 ? (byte) 0 : val > 255.0 ? (byte) 0xff
: (byte) (val + 0.5);
val = y - 0.34414 * (cb - 128) - 0.71414 * (cr - 128) - k;
val = (val - 128) * .65f + 128;
rgb[base + 1] = val < 0.0 ? (byte) 0 : val > 255.0 ? (byte) 0xff
: (byte) (val + 0.5);
val = y + 1.772 * (cb - 128) - k;
val = (val - 128) * .65f + 128;
rgb[base + 2] = val < 0.0 ? (byte) 0 : val > 255.0 ? (byte) 0xff
: (byte) (val + 0.5);
}
raster = Raster.createInterleavedRaster(new DataBufferByte(rgb,
rgb.length), w, h, w * 3, 3, new int[] { 0, 1, 2 }, null);
ColorSpace cs = ColorSpace.getInstance(ColorSpace.CS_sRGB);
ColorModel cm = new ComponentColorModel(cs, false, true,
Transparency.OPAQUE, DataBuffer.TYPE_BYTE);
return new BufferedImage(cm, (WritableRaster) raster, true, null);
}