class_respondsToSelector

class_respondsToSelector  判断某个类是否有某个实例方法，有则返回YES，否则返回NO

/** 
 * Returns a Boolean value that indicates whether instances of a class respond to a particular selector.
 * 
 * @param cls The class you want to inspect.
 * @param sel A selector.
 * 
 * @return \c YES if instances of the class respond to the selector, otherwise \c NO.
 * 
 * @note You should usually use \c NSObject's \c respondsToSelector: or \c instancesRespondToSelector: 
 *  methods instead of this function.
 */
OBJC_EXPORT BOOL class_respondsToSelector(Class cls, SEL sel) 
     __OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_2_0);

测试：

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    //其中printDZL是Person类的实例方法，printDZ是Person类的类方法
    Person * p1 = [[Person alloc] init];
    BOOL isOrNot = class_respondsToSelector([p1 class], @selector(printDZL));
    BOOL isOrNot2 = class_respondsToSelector([Person class], @selector(printDZ));
    NSLog(@"%i--%i", isOrNot, isOrNot2);
}

输出：

2015-11-04 13:53:33.019 02-runtime[3053:76771] 1--0