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javalearner

java在做图片类型转换时，JDK本身提供的类对 ??GIF->JPG   GIF->PNG   PNG->GIF(X)   PNG->JPG
这几种类型的转换支持比较好， 可以通过类直接转，代码如下:

1.      /**
   
2.       * Created on 2010-7-13  
   
3.       *

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Discription:[convert GIF->JPG GIF->PNG PNG->GIF(X) PNG->JPG ] * @param source * @param formatName * @param result * @author:[shixing_11@sina.com] */ public static void convert(String source, String formatName, String result) { try { File f = new File(source); f.canRead(); BufferedImage src = ImageIO.read(f); ImageIO.write(src, formatName, new File(result)); } catch (Exception e) { e.printStackTrace(); } } 但对于bmp格式转换成jpg，却没有直接的方法，都是通过第三方包进行转换，
下面是参考网上的一篇文章略做了修改后的bmp转jpg的程序：

1. import java.awt.Image;  
   
2. import java.awt.Toolkit;  
   
3. import java.awt.image.BufferedImage;  
   
4. import java.awt.image.MemoryImageSource;  
   
5. import java.io.FileInputStream;  
   
6. import java.io.FileOutputStream;  
   
7. import java.io.IOException;  
   
8. import com.sun.image.codec.jpeg.JPEGCodec;  
   
9. import com.sun.image.codec.jpeg.JPEGImageEncoder;  
   
10. public class BmpReader  
    
11. {  
    
12.      /**
    
13.       * Created on 2010-7-13  
    
14.       *

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Discription:[bmpTojpg] * @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 = "c:\img\bbb.bmp"; String dstFile = "c:\img\bbbimg.jpg"; bmpTojpg(srcfile,dstFile); } }

   
     
     
      
      

        
      

        
      
     
   

  


源码下载：http://file.javaxxz.com/2014/10/28/235550812.zip