把数据写到文件里面去用
vedioWriter= [[NSMutableData alloc] init];
//获取文件路径
NSString *uidplist = [[NSString alloc] initWithFormat:@"vediolist.text"];
NSArray *paths =NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
uidPath= [[paths objectAtIndex:0] stringByAppendingPathComponent:uidplist];
NSData *data2 = [NSData dataWithBytes:buf length:actualSize];
Byte*testByte = (Byte*)[data2bytes];
[vedioWriter appendBytes:testByte length:data2.length];
[vedioWriter writeToFile:uidPath atomically:YES];
注：不喜勿喷！！！
