ios 如何把后台反回的数据里面的null替换掉

-(NSMutableDictionary *)deleteNull

{

    if (self) {

        for (NSString * key in self) {

            if (self[key]==nil || [self[key] isEqual:[NSNull null]]) {

                [self setObject:@"" forKey:key];

            }

        }

    }

    return self;

}

 

 

-(NSMutableDictionary *)deleteNull

{

    if (self) {

        NSDictionary * dict=[[NSDictionary alloc]initWithDictionary:self];

        for (NSString * key in dict) {

            if ([[self objectForKey:key] isKindOfClass:[NSNull class]]) {

                [self setObject:@"" forKey:key];

            }

        }

    }

    return self;

}