//-应用程序的Documents路径。
NSArray * paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString * docDir = [paths objectAtIndex:0];
//创建子目录
NSString * mydir= [docDir stringByAppendingPathComponent:@"mydir"];
//添加文件名
NSString * picFile= [frontpagedir stringByAppendingPathComponent:[NSString stringWithFormat:@"%@",picname]];
NSFileManager * fm = [NSFileManager defaultManager];
//如果文件夹不存在创建
if([fm fileExistsAtPath:mydir] == NO ) {
//中间的路径也会一同生成。
[fm createDirectoryAtPath:mydir withIntermediateDirectories:YES attributes:nil error:nil];
}
//存储文件
[fm createFileAtPath:self.picpath contents:data attributes:nil];
//删除文件
[fm createFileAtPath:self.picpath contents:data attributes:nil];