字符串判空

#import <Foundation/Foundation.h>

@interface NSObject (DCNull)


/**
 判断一个对象是否为空

 @return 是否为空
 */
- (BOOL)dc_isNull;

@end

#import "NSObject+DCNull.h"

@implementation NSObject (DCNull)

#pragma mark - 判断一个对象是否为空
- (BOOL)dc_isNull
{
    if ([self isEqual:[NSNull null]]) {
        return YES;
        
    }else if ([self isEqual:[NSNull class]]){
        return YES;
    }else{
        if (self == nil) {
            return YES;
        }
    }
    
    if ([self isKindOfClass:[NSString class]]) {
        if ([((NSString *)self) isEqualToString:@"(null)"]) {
            return YES;
        }
    }
    
    return NO;
}


@end