import java.awt.Image;import java.awt.Toolkit;import java.awt.image.BufferedImage;import java.awt.image.MemoryImageSource;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import com.sun.image.codec.jpeg.JPEGCodec;import com.sun.image.codec.jpeg.JPEGImageEncoder; public class BmpReader {     /**     * 图片格式转换 BMP -> JPG     * @param file     * @param dstFile     */    public static void bmpTojpg(String file, String dstFile) {        try {            FileInputStream in = new FileInputStream(file);            Image TheImage = read(in);            int wideth = TheImage.getWidth(null);            int height = TheImage.getHeight(null);            BufferedImage tag = new BufferedImage(wideth, height,BufferedImage.TYPE_INT_RGB);            tag.getGraphics().drawImage(TheImage, 0, 0, wideth, height, null);            FileOutputStream out = new FileOutputStream(dstFile);            JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);            encoder.encode(tag);            out.close();        } catch (Exception e) {            System.out.println(e);        }    }     public static int constructInt(byte[] in, int offset) {        int ret = ((int) in[offset + 3] & 0xff);        ret = (ret << 8) | ((int) in[offset + 2] & 0xff);        ret = (ret << 8) | ((int) in[offset + 1] & 0xff);        ret = (ret << 8) | ((int) in[offset + 0] & 0xff);        return (ret);    }     public static int constructInt3(byte[] in, int offset) {        int ret = 0xff;        ret = (ret << 8) | ((int) in[offset + 2] & 0xff);        ret = (ret << 8) | ((int) in[offset + 1] & 0xff);        ret = (ret << 8) | ((int) in[offset + 0] & 0xff);        return (ret);    }     public static long constructLong(byte[] in, int offset) {        long ret = ((long) in[offset + 7] & 0xff);        ret |= (ret << 8) | ((long) in[offset + 6] & 0xff);        ret |= (ret << 8) | ((long) in[offset + 5] & 0xff);        ret |= (ret << 8) | ((long) in[offset + 4] & 0xff);        ret |= (ret << 8) | ((long) in[offset + 3] & 0xff);        ret |= (ret << 8) | ((long) in[offset + 2] & 0xff);        ret |= (ret << 8) | ((long) in[offset + 1] & 0xff);        ret |= (ret << 8) | ((long) in[offset + 0] & 0xff);        return (ret);    }     public static double constructDouble(byte[] in, int offset) {        long ret = constructLong(in, offset);        return (Double.longBitsToDouble(ret));    }     public static short constructShort(byte[] in, int offset) {        short ret = (short) ((short) in[offset + 1] & 0xff);        ret = (short) ((ret << 8) | (short) ((short) in[offset + 0] & 0xff));        return (ret);    }     static class BitmapHeader {        public int iSize, ibiSize, iWidth, iHeight, iPlanes, iBitcount,                iCompression, iSizeimage, iXpm, iYpm, iClrused, iClrimp;         // 读取bmp文件头信息        public void read(FileInputStream fs) throws IOException {            final int bflen = 14;            byte bf[] = new byte[bflen];            fs.read(bf, 0, bflen);            final int bilen = 40;            byte bi[] = new byte[bilen];            fs.read(bi, 0, bilen);            iSize = constructInt(bf, 2);            ibiSize = constructInt(bi, 2);            iWidth = constructInt(bi, 4);            iHeight = constructInt(bi, 8);            iPlanes = constructShort(bi, 12);            iBitcount = constructShort(bi, 14);            iCompression = constructInt(bi, 16);            iSizeimage = constructInt(bi, 20);            iXpm = constructInt(bi, 24);            iYpm = constructInt(bi, 28);            iClrused = constructInt(bi, 32);            iClrimp = constructInt(bi, 36);        }    }     public static Image read(FileInputStream fs) {        try {            BitmapHeader bh = new BitmapHeader();            bh.read(fs);            if (bh.iBitcount == 24) {                return (readImage24(fs, bh));            }            if (bh.iBitcount == 32) {                return (readImage32(fs, bh));            }            fs.close();        } catch (IOException e) {            System.out.println(e);        }        return (null);    }     // 24位    protected static Image readImage24(FileInputStream fs, BitmapHeader bh)            throws IOException {        Image image;        if (bh.iSizeimage == 0) {            bh.iSizeimage = ((((bh.iWidth * bh.iBitcount) + 31) & ~31) >> 3);            bh.iSizeimage *= bh.iHeight;        }        int npad = (bh.iSizeimage / bh.iHeight) - bh.iWidth * 3;        int ndata[] = new int[bh.iHeight * bh.iWidth];        byte brgb[] = new byte[(bh.iWidth + npad) * 3 * bh.iHeight];        fs.read(brgb, 0, (bh.iWidth + npad) * 3 * bh.iHeight);        int nindex = 0;        for (int j = 0; j < bh.iHeight; j++) {            for (int i = 0; i < bh.iWidth; i++) {                ndata[bh.iWidth * (bh.iHeight - j - 1) + i] = constructInt3(                        brgb, nindex);                nindex += 3;            }            nindex += npad;        }        image = Toolkit.getDefaultToolkit().createImage(                new MemoryImageSource(bh.iWidth, bh.iHeight, ndata, 0,                        bh.iWidth));        fs.close();        return (image);    }     // 32位    protected static Image readImage32(FileInputStream fs, BitmapHeader bh)            throws IOException {        Image image;        int ndata[] = new int[bh.iHeight * bh.iWidth];        byte brgb[] = new byte[bh.iWidth * 4 * bh.iHeight];        fs.read(brgb, 0, bh.iWidth * 4 * bh.iHeight);        int nindex = 0;        for (int j = 0; j < bh.iHeight; j++) {            for (int i = 0; i < bh.iWidth; i++) {                ndata[bh.iWidth * (bh.iHeight - j - 1) + i] = constructInt3(                        brgb, nindex);                nindex += 4;            }        }        image = Toolkit.getDefaultToolkit().createImage(                new MemoryImageSource(bh.iWidth, bh.iHeight, ndata, 0,                        bh.iWidth));        fs.close();        return (image);    }     public static void main(String[] args) {        String srcfile = "D:\\33.bmp";        String dstFile = "D:\\33.jpg";        bmpTojpg(srcfile, dstFile);    } }