iOS 数据持久化

• user defaults：
  NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
   
  [userDefaults setBool:YES forKey:@"Key1"];
  [userDefaults setInteger:123 forKey:@"Key2"];
  [userDefaults setObject:@"Some Object" forKey:@"Key3"];
   
  [userDefaults boolForKey:@"Key1"];
  [userDefaults integerForKey:@"Key2"];
  [userDefaults objectForKey:@"Key3"];
   
  [userDefaults synchronize];
• property lists：
  NSArray *fruits = @[@"Apple", @"Mango", @"Pineapple", @"Plum", @"Apricot"];
   
  NSString *filePathFruits = [documents stringByAppendingPathComponent:@"fruits.plist"];
  [fruits writeToFile:filePathFruits atomically:YES];
   
  NSDictionary *miscDictionary = @{@"anArray" : fruits, @"aNumber" : @12345, @"aBoolean" : @YES};
   
  NSString *filePathDictionary = [documents stringByAppendingPathComponent:@"misc-dictionary.plist"];
  [miscDictionary writeToFile:filePathDictionary atomically:YES];
   
  NSArray *loadedFruits = [NSArray arrayWithContentsOfFile:filePathFruits];
  NSLog(@"Fruits Array > %@", loadedFruits);
   
  NSDictionary *loadedMiscDictionary = [NSDictionary dictionaryWithContentsOfFile:filePathDictionary];
  NSLog(@"Misc Dictionary > %@", loadedMiscDictionary);
• SQLite
• Core Data