假设你要上传的数组为：
  NSMutableArray *imgArray = [NSMutableArray arrayWithObjects:@"下标为0",@"下标为 1",@"下标为2",@"下标为3",@"下标为4",@"下标为5", nil];
   // 存放参数的字典为
   NSMutableDictionary * parmar = [NSMutableDictionary dictionary];


   方案一：把数组转化为相应的字符串，看代码
  NSMutableArray *array = [NSMutableArray arrayWithCapacity: imgArray.count];
      for (UIModel *model in imgArray) {
           [array addObject:model.staffid];
     }
      [parmar setObject:[array componentsJoinedByString:@","] forKey:@"imgArr"];

   方案二：
   NSData *jsonData = [NSJSONSerialization dataWithJSONObject:array       options:NSJSONWritingPrettyPrinted error:nil];
    [parmar setObject:[[NSString alloc]initWithData:jsonData    encoding:NSUTF8StringEncoding] forKey:@"imgArr"];