iOS解决json串中的NSNull类型

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我的博客原文地址

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

（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];// 打印的结果{    "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;}

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