NSMutableArray *tempArr = [NSMutableArray array];
    NSMutableDictionary *dic = [NSMutableDictionary dictionary];
    for (int i = 0; i < self.dataSourceArr.count; i++) {
    //便利一下陣列得到模型，這裡不能用for - in ，拿到模型之後把值取出來放入可變字典中
        PerponModel *model = self.dataSourceArr[i];
        [dic setValue:model.name
 
 forKey:@"realname"];
        [dic setValue:model.phoneNumber forKey:@"mobile"];
        [tempArr addObject:dic];
    }
    //tempArr是一個可變陣列
    //NSJSONWritingPrettyPrinted是一個列舉
    //dataWithJSONObject:(這個是一個id型別的可以是字典，字典放進去就可以把字典轉成json)
    NSData *data = [NSJSONSerialization dataWithJSONObject:tempArr options:NSJSONWritingPrettyPrinted error:nil
 
];
    NSString *str = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];