ios的url编码问题

2018-05-02

ios的url编码我们通常都直接用系统的：

1	[strToEncode stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLPathAllowedCharacterSet]];

可是如果发给服务端，那么会发现某些字符会不对，比如：+ 号会被转为空格。原因是URLPathAllowedCharacterSet包含的特殊字符集不够：

URLFragmentAllowedCharacterSet  "#%<>[\]^`{|}  
URLHostAllowedCharacterSet      "#%/<>?@\^`{|}  
URLPasswordAllowedCharacterSet  "#%/:<>?@[\]^`{|}  
URLPathAllowedCharacterSet      "#%;<>?[\]^`{|}  
URLQueryAllowedCharacterSet     "#%<>[\]^`{|}  
URLUserAllowedCharacterSet      "#%/:<>?@[\]^`

可以看到URLQueryAllowedCharacterSet并不包含+。

所以我们需要自定义字符集：

+ (NSString *)urlEncodeForStr:(NSString *)str {
    NSString *charactersToEscape = @"?!@#$^&%*+,:;='\"`<>()[]{}/\\| ";
    NSCharacterSet *allowedCharacters = [[NSCharacterSet characterSetWithCharactersInString:charactersToEscape] invertedSet];
    return [str stringByAddingPercentEncodingWithAllowedCharacters:allowedCharacters];
}