iOS开发解决json串中的NSNull类型

后端返回的数据中总会出现一些NSNull类型，当我们一处理程序就会崩溃，因此想到把返回的数据中的NSNull类型全部转换成@""空字符串。下面是转化方法：

1 自定义的几个方法：放在NSDictionary类别中

#pragma mark - 私有方法

//将NSDictionary中的Null类型的项目转化成@""

+(NSDictionary *)nullDic:(NSDictionary *)myDic

{

NSArray *keyArr = [myDic allKeys];

NSMutableDictionary *resDic = [[NSMutableDictionary alloc]init];

for (int i = 0; i < keyArr.count; i ++)

{

id obj = [myDic objectForKey:keyArr[i]];

obj = [self changeType:obj];

[resDic setObject:obj forKey:keyArr[i]];

}

return resDic;

}

//将NSDictionary中的Null类型的项目转化成@""

+(NSArray *)nullArr:(NSArray *)myArr

{

NSMutableArray *resArr = [[NSMutableArray alloc] init];

for (int i = 0; i < myArr.count; i ++)

{

id obj = myArr[i];

obj = [self changeType:obj];

[resArr addObject:obj];

}

return resArr;

}

//将NSString类型的原路返回

+(NSString *)stringToString:(NSString *)string

{

return string;

}

//将Null类型的项目转化成@""

+(NSString *)nullToString

{

return @"";

}

#pragma mark - 公有方法

//类型识别:将所有的NSNull类型转化成@""

+(id)changeType:(id)myObj

{

if ([myObj isKindOfClass:[NSDictionary class]])

{

return [self nullDic:myObj];

}

else if([myObj isKindOfClass:[NSArray class]])

{

return [self nullArr:myObj];

}

else if([myObj isKindOfClass:[NSString class]])

{

return [self stringToString:myObj];

}

else if([myObj isKindOfClass:[NSNull class]])

{

return [self nullToString];

}

else

{

return myObj;

}

}

2 使用方法（绿色的是实际用到的代码）

（1）原始的json串：后端返回的json串里面包含类型NSString，NSArray，NSDictionary，NSNull类型。

{"status":1,"service_name":null,"service_id":null,"img_url":"http:\/\/api.jgfw.me\/assets\/uploads\/files\/","price":null,"num":3,"service_info":{"service_type":null,"service_time":null,"service_detail":null,"customer_name":null,"customer_phone":null,"customer_address":"","new_jishi":"","old_jishi":null,"lat":null,"lon":null},"order_info":{"order_no":"E15031267469289848688","pay_time":null,"order_time":null,"price":0,"order_state":null}}

 

（2）用SBJson库:json串转换成字典

NSDictionary *jsonDic = [retString JSONValue];

（3）用自定义方法转换后的结果：将字典中所有的NSNull类型转换成@""

NSDictionary *dict = [NSDictionary changeType:jsonDic];

{

    "img_url" = "http://api.jgfw.me/assets/uploads/files/";

    num = 3;

    "order_info" =     {

        "order_no" = E15031267469289848688;

        "order_state" = "";

        "order_time" = "";

        "pay_time" = "";

        price = 0;

    };

    price = "";

    "service_id" = "";

    "service_info" =     {

        "customer_address" = "";

        "customer_name" = "";

        "customer_phone" = "";

        lat = "";

        lon = "";

        "new_jishi" = "";

        "old_jishi" = "";

        "service_detail" = "";

        "service_time" = "";

        "service_type" = "";

    };

    "service_name" = "";

    status = 1;

}