如何在iphone中从web服务获取%

我是iPhone开发的新手。我正在开发一个聊天应用程序。我在发送和接收一些特殊字符时遇到了问题。最后，我成功地发布并获得了这个特殊字符。现在，只有一个特殊字符我无法获得。当我向web服务发送%时，我得到了%25

在向web服务发送字符串时，请使用下面的字符串

NSString *string = @"Hello % How Are You?";
string = [string stringByReplacingOccurrencesOfString:@"%" withString:@"%25"];
NSLog(@"\n\n ===>> Before ==>> %@",string);
NSString *string2 = string;
string2 = [string2 stringByReplacingOccurrencesOfString:@"%25" withString:@"%"];
NSLog(@"\n\n ===>> After ==>> %@",string2);

输出=>

===>> Before ==>> Hello%2520%2525%2520how%2520are%2520you?

 ===>> After ==>> Hello %2526 How Are You?

请尝试此代码

NSString *string = @"Hello % How Are You?";

string = [string stringByReplacingOccurrencesOfString:@"&" withString:@"&"];
string = [string stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
string = [string stringByReplacingOccurrencesOfString:@"&" withString:@"%26"];
NSLog(@"\n\n ===>> Before ==>> %@",string);

NSString *string2 = string;

string2 = [string2 stringByReplacingOccurrencesOfString:@"%20" withString:@" "];
string2 = [string2 stringByReplacingOccurrencesOfString:@"%26" withString:@"&"];
string2 = [string2 stringByReplacingOccurrencesOfString:@"%25" withString:@"%"];    
NSLog(@"\n\n ===>> After ==>> %@",string2);

输出为：

===>> Before ==>> Hello%20%25%20How%20Are%20You?
====>> After ==>> Hello % How Are You?

---

Em在发送笑脸时仍然面临问题。如果我发送了多个笑脸，但没有在两个笑脸之间提供任何规格，那么实际会发生什么情况。如果我发送了两个以上的笑脸，那么我会使用特殊字符。你能帮我吗？