1.4.2.2. PATHS（Core Data 应用程序实践指南）

　　持久化存储文件在文件系统中的位置

1. 先获取应用程序文档目录的路径

   1. #pragma mark - PATHS
      - (NSString *)applicationDocumentsDirectory {
          if (debug == 1) {
              NSLog(@"Running %@ '%@'",self.class, NSStringFromSelector(_cmd));
          }
          
          return [NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES) lastObject];
      }

2. 返回包含Stores的子目录路径的NSURL，如果没有则创建

   1. - (NSURL *)applicationStoresDirectory {
          if (debug == 1) {
              NSLog(@"Running %@ '%@'",self.class, NSStringFromSelector(_cmd));
          }
          
          NSURL *storesDirectory = [[NSURL fileURLWithPath:[self applicationDocumentsDirectory]] URLByAppendingPathComponent:@"Stores"];
          
          NSFileManager *fileManager = [NSFileManager defaultManager];
          if (![fileManager fileExistsAtPath:[storesDirectory path]]) {
              NSError *error = nil;
              if ([fileManager createDirectoryAtURL:storesDirectory withIntermediateDirectories:YES attributes:nil error:&error]) {
                  if (debug == 1) {
                      NSLog(@"Running %@ '%@'",self.class, NSStringFromSelector(_cmd));
                  }else{
                      NSLog(@"FAILD to Create Stores directory:%@",error);
                  }
                  
              }
          }
          
          return storesDirectory;
      }

3. 返回完整路径

   1. - (NSURL *)storeURL {
          if (debug == 1) {
              NSLog(@"Running %@ '%@'",self.class, NSStringFromSelector(_cmd));
          }
          return [[self applicationStoresDirectory] URLByAppendingPathComponent:storeFilename];
      }