iOS local storage NSUserDefaults encapsulation code

#import <Foundation/>
@interface NSUserDefaultUtil : NSObject
+(void)PutDefaults:(NSString *)key Value:(id)value;
+(id)GetDefaults:(NSString *)key;
@end

#import ""
@implementation NSUserDefaultUtil
+(void)PutDefaults:(NSString *)key Value:(id)value{
 if (key!=NULL&&value!=NULL) {
  NSUserDefaults *userDefaults=[NSUserDefaults standardUserDefaults];
  [userDefaults setObject:value forKey:key];
 }
}
+(id)GetDefaults:(NSString *)key{
 NSUserDefaults *userDefaults=[NSUserDefaults standardUserDefaults];
 id obj;
 if (key!=NULL) {
  obj=[userDefaults objectForKey:key];
 }
 return obj;
}
@end

[NSUserDefaultUtil PutDefaults:@"key" Value:str];
 = [NSUserDefaultUtil GetDefaults:@"key"];