cmyk转rgb

package com.lasun.acms.action;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
import java.awt.Transparency;
import java.awt.color.ColorSpace;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.ComponentColorModel;
import java.awt.image.DataBuffer;
import java.awt.image.DataBufferByte;
import java.awt.image.Raster;
import java.awt.image.WritableRaster;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Iterator;
import javax.imageio.IIOException;
import javax.imageio.ImageIO;
import javax.imageio.ImageReader;
import javax.imageio.stream.ImageInputStream;
public class  {
	  public void readImage(String filename) throws IOException {        
	       File file = new File(filename);
	        ImageInputStream input = ImageIO.createImageInputStream(file);
	        Iterator readers = ImageIO.getImageReaders(input);
	        if(readers == null || !readers.hasNext()) {
	            throw new RuntimeException("1 No ImageReaders found");
	        }
	        ImageReader reader = (ImageReader) readers.next();
	        reader.setInput(input);
	        String format = reader.getFormatName() ;
	        BufferedImage image; 
	       
	      if ( "JPEG".equalsIgnoreCase(format) ||"JPG".equalsIgnoreCase(format) )   {            
	        try {  
	            
	            image = reader.read(0); //RGB
	        } catch (IIOException e) {  
	            // 读取Raster (没有颜色的转换).   
	            Raster raster = reader.readRaster(0, null);//CMYK  
	            image = createJPEG4(raster);
	        } 
	           image.getGraphics().drawImage(image, 0, 0, null);
	           String newfilename = filename.substring(0,filename.lastIndexOf("."))+"_rgb"+filename.substring(filename.lastIndexOf("."));
	           File newFile = new File(newfilename);
	           FileOutputStream out = new FileOutputStream(newFile);
	           JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
	           encoder.encode(image);
	           out.flush();
	           out.close();  
	            
	        }
	    }
	    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);
	    }
	   public static void main(String[] args) throws IOException 
	    { 
	          String filename = "e:/28531383187802097.jpg";
	          
	          CMYK cm = new CMYK();
	          cm.readImage(filename);
	                   
	    } 
}