16/08/04/wed
NSFileManager操作小结：
① 直接在沙盒目录下添加文件: 此种情况下，沙盒路径下可以写入文件
NSString *cachespath = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0];
NSString *local = [cachespath stringByAppendingPathComponent:@"heihei.txt"];
NSString *test = @"this is a test code";
[test writeToFile:local atomically:YES encoding:NSUTF8StringEncoding error:nil];
② 在沙盒路径下自己添加文件夹：此种情况下，直接在自己拼接的路径下面写入文件是无效的
NSString *cachespath = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0];
NSString *local = [cachespath stringByAppendingPathComponent:@"haha/heihei.txt"];
NSString *test = @"this is a test code";
[test writeToFile:local atomically:YES encoding:NSUTF8StringEncoding error:nil];
//这个路径不会创建，自然文件也不能写入进去
对于②问题的解决办法是：自己拼接想要创建的路径，然后判断此路径是否存在，不存在的话就创建路径。再在路径下写入文件，代码如下
NSString *cachespath = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0];
NSString *local = [cachespath stringByAppendingPathComponent:@"hehe/haha"];
if (![[NSFileManager defaultManager] fileExistsAtPath:local]) {
[[NSFileManager defaultManager] createDirectoryAtPath:local withIntermediateDirectories:YES attributes:nil error:nil];
}
NSString *final = [local stringByAppendingPathComponent:@"heihei.txt"];
NSString *test = @"this is a test code";
[test writeToFile:final atomically:YES encoding:NSUTF8StringEncoding error:nil];
