iOS下URL编码

使用NSString默认的URL编码,会对汉字等进行转义,但是对=+等这些字符不会进行转义

所以要手动实现这些字符的转义

- (NSString *)encodeToPercentEscapeString: (NSString *) input
{
    // Encode all the reserved characters, per RFC 3986
    // (<http://www.ietf.org/rfc/rfc3986.txt>)
    NSString *outputStr = (NSString *)
    CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,
                                            (CFStringRef)input,
                                            NULL,
                                            (CFStringRef)@"!*‘();:@&=+$,/?%#[]",
                                            kCFStringEncodingUTF8);
    return outputStr;
}  

- (NSString *)decodeFromPercentEscapeString: (NSString *) input
{
    NSMutableString *outputStr = [NSMutableString stringWithString:input];
    [outputStr replaceOccurrencesOfString:@"+"
                               withString:@" "
                                  options:NSLiteralSearch
                                    range:NSMakeRange(0, [outputStr length])];  

    return [outputStr stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
}  

测试代码

NSString * testUrl      = @"http://search.google.com?keywords=($# it‘s {a*123})00!*‘();:@&=+$,/?%#[]";
NSLog(@"original: %@", testUrl);  

NSString * encodeStr    = [self encodeToPercentEscapeString:testUrl];
NSLog(@"encoded: %@", encodeStr);  

NSString * encodeStr2   = [testUrl stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSLog(@"encoded2:%@", encodeStr2);  

NSString * decodeStr    = [self decodeFromPercentEscapeString:encodeStr];
NSLog(@"decoded: %@", decodeStr);  

结果

>> original: http://search.google.com?keywords=($# it‘s {a*123})00!*‘();:@&=+$,/?%#[]
>> encoded:  http%3A%2F%2Fsearch.google.com%3Fkeywords%3D%28%24%23%20it%27s%20%7Ba%2A123%7D%2900%21%2A%27%28%29%3B%3A%40%26%3D%2B%24%2C%2F%3F%25%23%5B%5D
>> encoded2: http://search.google.com?keywords=($%23%20it‘s%20%7Ba*123%7D)00!*‘();:@&=+$,/?%25%23%5B%5D
>> decoded:  http://search.google.com?keywords=($# it‘s {a*123})00!*‘();:@&=+$,/?%#[] 

转自:http://blog.csdn.net/kesalin/article/details/6678939