首先感谢

https://www.cnblogs.com/interdrp/p/7076202.html

https://blog.csdn.net/ybn187/article/details/52185269

https://blog.csdn.net/keketrtr/article/details/88129641。

 

package test;import com.joyhua.utils.CMYKUtil;
import com.joyhua.utils.CMYKUtil1;
import net.coobird.thumbnailator.Thumbnails;import javax.imageio.ImageIO;
import javax.imageio.ImageReader;
import javax.imageio.stream.ImageInputStream;
import java.awt.image.BufferedImage;
import java.awt.image.Raster;
import java.awt.image.RenderedImage;
import java.io.File;
import java.io.IOException;
import java.util.*;public class test4 {public static void main(String[] args) {String sourceString = "E:\\test\\p1.jpg";File source = new File(sourceString);String toString = "E:\\test\\p1_rgb.jpg";File to = new File(toString);String toString1 = "E:\\test\\p1_s.jpg";File to1 = new File(toString);try {Thumbnails.of(CMYKUtil.readImage(source)).width(500).height(704).outputFormat("jpg").toFile(to1);//图片是cmyk，需要转换为rgb// Thumbnails.of(source).width(500).height(704).outputFormat("jpg").toFile(to);} catch (IOException e) {e.printStackTrace();}}
}

package com.joyhua.utils;import org.apache.log4j.Logger;import javax.imageio.IIOException;
import javax.imageio.ImageIO;
import javax.imageio.ImageReader;
import javax.imageio.stream.ImageInputStream;
import java.awt.*;
import java.awt.color.ColorSpace;
import java.awt.image.*;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.Iterator;/*** CREATE BY zz ON 2019-03-26**/
public class CMYKUtil {static Logger log = Logger.getLogger(CMYKUtil.class);/*** @description: CMYK格式图片转RGB格式图片的处理，因为Thumbnails无法处理CMYK格式图片*/public static BufferedImage readImage(File file) throws IOException {return readImage(ImageIO.createImageInputStream(file));}public static BufferedImage readImage(InputStream stream) throws IOException {return readImage(ImageIO.createImageInputStream(stream));}public static BufferedImage readImage(ImageInputStream input) throws IOException {Iterator<?> readers = ImageIO.getImageReaders(input);if (readers == null || !readers.hasNext()) {return null;}ImageReader reader = (ImageReader) readers.next();reader.setInput(input);BufferedImage image;try {// 尝试读取图片 (包括颜色的转换).image = reader.read(0); //RGB} catch (IIOException e) {// 读取Raster (没有颜色的转换).Raster raster = reader.readRaster(0, null);//CMYKimage = createJPEG4(raster);}return image;}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);}
}

 

转换完后会发现图片颜色不对了，需要引入一下三个maven

<dependency><groupId>com.twelvemonkeys.imageio</groupId><artifactId>imageio-jpeg</artifactId><version>3.5</version></dependency><dependency><groupId>com.twelvemonkeys.imageio</groupId><artifactId>imageio-tiff</artifactId><version>3.5</version></dependency><dependency><groupId>com.twelvemonkeys.servlet</groupId><artifactId>servlet</artifactId><version>3.5</version></dependency>

jdk的ImageIO有自动发现功能，会自动查找相关的编解码类并使用，而不使用jdk默认的编解码类,所以使用这个库是完全无入侵的。