ios 从网络下载图片，保存，并用imageview从保存中显示

-(UIImage *) getImageFromURL:(NSString *)fileURL {
NSLog(@"执行图片下载函数");
UIImage * result;

NSData * data = [NSData dataWithContentsOfURL:[NSURL URLWithString:fileURL]];
result = [UIImage imageWithData:data];

return result;
}

-(void) saveImage:(UIImage *)image withFileName:(NSString *)imageName ofType:(NSString *)extension inDirectory:(NSString *)directoryPath {
if ([[extension lowercaseString] isEqualToString:@"png"]) {
[UIImagePNGRepresentation(image) writeToFile:[directoryPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.%@", imageName, @"png"]] options:NSAtomicWrite error:nil];
} else if ([[extension lowercaseString] isEqualToString:@"jpg"] || [[extension lowercaseString] isEqualToString:@"jpeg"]) {
[UIImageJPEGRepresentation(image, 1.0) writeToFile:[directoryPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.%@", imageName, @"jpg"]] options:NSAtomicWrite error:nil];
} else {
//ALog(@"Image Save Failed\nExtension: (%@) is not recognized, use (PNG/JPG)", extension);
NSLog(@"文件后缀不认识");
}
}

-(UIImage *) loadImage:(NSString *)fileName ofType:(NSString *)extension inDirectory:(NSString *)directoryPath {
UIImage * result = [UIImage imageWithContentsOfFile:[NSString stringWithFormat:@"%@/%@.%@", directoryPath, fileName, extension]];

return result;
}

NSString * documentsDirectoryPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSLog(@"保存路径:%@",documentsDirectoryPath);
//Get Image From URL
UIImage * imageFromURL = [self getImageFromURL:@"http://file.duteba.com/phone/2009/04/5/ftGxL8kcUL.jpg"];

//Save Image to Directory
[self saveImage:imageFromURL withFileName:@"MyImage" ofType:@"jpg" inDirectory:documentsDirectoryPath];

//Load Image From Directory
UIImage * imageFromWeb = [self loadImage:@"MyImage" ofType:@"jpg" inDirectory:documentsDirectoryPath];
[img setImage:imageFromWeb];

//取得目录下所有文件名
NSArray *file = [[[NSFileManager alloc] init] subpathsAtPath:documentsDirectoryPath];
//NSLog(@"%d",[file count]);
NSLog(@"%@",file);

//如何获取下载的文件的完整路径?

NSString *documentsDirectory2 = [path2 objectAtIndex:0]; //path数组里貌似只有一个元素
//字符串拼接得到文件完整路径
NSString *filestr = @"/MyImage.jpg";
NSString *newstr = [documentsDirectory2 stringByAppendingString:filestr];
NSLog(@"完整路径是:%@",newstr);

NSData *dd = [NSData dataWithContentsOfFile:newstr];
[img222 setImage:[UIImage imageWithData:dd]];