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;
}