swift 表情编码与解码

// 编码：
let contentString1 = contentString.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)!
print("编码后：",contentString1)

// 解码:
let contentString2 = contentString.removingPercentEncoding!
print("解码后：",contentString2)

原文: https://www.jianshu.com/p/34819e42f302