iOS JSON字符串转化为字典-字典转Json字符串-

1. JSON字符串转化为字典

+ (NSDictionary *)dictionaryWithJsonString:(NSString *)jsonString    {    
       if (jsonString == nil) {
                 return nil; 
        } 
      NSData *jsonData = [jsonString dataUsingEncoding:NSUTF8StringEncoding];
      NSError *err; NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:&err];
      if(err){
                NSLog(@"json解析失败：%@",err);
                return nil;
              }
       return dic;    
}

2. 字典转Json字符串    // 字典转json字符串方法    
                                                                                                                                
-(NSString *)convertToJsonData:(NSDictionary *)dict{
    NSError *error; NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dict   options:NSJSONWritingPrettyPrinted error:&error];
    NSString *jsonString;
    if (!jsonData) {
              NSLog(@"%@",error);
    }else{
        jsonString = [[NSString alloc]initWithData:jsonData encoding:NSUTF8StringEncoding];
  }
    NSMutableString *mutStr = [NSMutableString stringWithString:jsonString];
    NSRange range = {0,jsonString.length
  };

//去掉字符串中的空格
    [mutStr replaceOccurrencesOfString:@" " withString:@"" options:NSLiteralSearch range:range];
    NSRange range2 = {0,mutStr.length};
    //去掉字符串中的换行符
    [mutStr replaceOccurrencesOfString:@"\n" withString:@"" options:NSLiteralSearch range:range2];
    return mutStr;
  }