剛需要用到接受到的jpg二進制文件，直接在內存做解析，mark一下，下面給出測試代碼。
FILE *file;
file = fopen("D:/221606322483223.jpg", "rb");
fseek(file, 0, SEEK_END);
fpos_t pos;
fgetpos(file, &pos);
char *data = new char[pos];
fseek(file, 0, 0);
int sjinum=fread(data, sizeof(char), pos, file);
fclose(file);
CvMat mat = cvMat(239, 251, CV_8UC3, data);
IplImage *pIplImage = cvDecodeImage(&mat, 1);
cvSaveImage("D:/2.jpg", pIplImage);
delete[]data;
Mat mtx(pIplImage);
Mat nmat=mtx.clone();
cvReleaseImage(&pIplImage);