读取bmp图片数据

 public  void getBMPImage(String source) throws Exception {

          clearNData();                        //清除数据保存区

          FileInputStream fs = null;

         try {

             fs = new FileInputStream(source);

             int bfLen = 14;

             byte bf[] = new byte[bfLen];

             fs.read(bf, 0, bfLen); // 读取14字节BMP文件头

             int biLen = 40;

             byte bi[] = new byte[biLen];

             fs.read(bi, 0, biLen); // 读取40字节BMP信息头

             // 源图宽度

             nWidth = (((int) bi[7] & 0xff) << 24)

                     | (((int) bi[6] & 0xff) << 16)

                     | (((int) bi[5] & 0xff) << 8) | (int) bi[4] & 0xff;

             // 源图高度

             nHeight = (((int) bi[11] & 0xff) << 24)

                     | (((int) bi[10] & 0xff) << 16)

                     | (((int) bi[9] & 0xff) << 8) | (int) bi[8] & 0xff;

             // 位数

             nBitCount = (((int) bi[15] & 0xff) << 8) | (int) bi[14] & 0xff;

             // 源图大小

             int nSizeImage = (((int) bi[23] & 0xff) << 24)

                     | (((int) bi[22] & 0xff) << 16)

                     | (((int) bi[21] & 0xff) << 8) | (int) bi[20] & 0xff;

             // 对24位BMP进行解析

             if (nBitCount == 24){

                 int nPad = (nSizeImage / nHeight) - nWidth * 3;

                 nData = new int[nHeight * nWidth];

                 nB=new int[nHeight * nWidth];

                 nR=new int[nHeight * nWidth];

                 nG=new int[nHeight * nWidth];

                 byte bRGB[] = new byte[(nWidth + nPad) * 3 * nHeight];

                 fs.read(bRGB, 0, (nWidth + nPad) * 3 * nHeight);

                 int nIndex = 0;

                 for (int j = 0; j < nHeight; j++){

                     for (int i = 0; i < nWidth; i++) {

                         nData[nWidth * (nHeight - j - 1) + i] = (255 & 0xff) << 24

                                 | (((int) bRGB[nIndex + 2] & 0xff) << 16)

                                  | (((int) bRGB[nIndex + 1] & 0xff) << 8)

                                 | (int) bRGB[nIndex] & 0xff;

                         nB[nWidth * (nHeight - j - 1) + i]=(int) bRGB[nIndex]& 0xff;

                         nG[nWidth * (nHeight - j - 1) + i]=(int) bRGB[nIndex+1]& 0xff;

                         nR[nWidth * (nHeight - j - 1) + i]=(int) bRGB[nIndex+2]& 0xff;

                         nIndex += 3;

                     }

                     nIndex += nPad;

                 }

  //               Toolkit kit = Toolkit.getDefaultToolkit();

  //               image = kit.createImage(new MemoryImageSource(nWidth, nHeight,

  //                       nData, 0, nWidth));

 /*

 //调试数据的读取

                 FileWriter fw = new FileWriter("C:\\Documents and Settings\\Administrator\\My Documents\\nDataRaw.txt");//创建新文件

                 PrintWriter out = new PrintWriter(fw);

                 for(int j=0;j<nHeight;j++){

                  for(int i=0;i<nWidth;i++){

                   out.print((65536*256+nData[nWidth * (nHeight - j - 1) + i])+"_"

                     +nR[nWidth * (nHeight - j - 1) + i]+"_"

                     +nG[nWidth * (nHeight - j - 1) + i]+"_"

                     +nB[nWidth * (nHeight - j - 1) + i]+" ");

                  }

                  out.println("");

                 }

                 out.close();

 */

             }

         }

         catch (Exception e) {

             e.printStackTrace();

             throw new Exception(e);

         }

         finally {

             if (fs != null) {

                 fs.close();

             }

         }

      //   return image;

     }