在實(shí)際開(kāi)發(fā)工作中,我們進(jìn)行http數(shù)據(jù)請(qǐng)求傳輸時(shí),有時(shí)候會(huì)用到Base64的編碼格式,對(duì)參數(shù)進(jìn)行重新編發(fā).

而B(niǎo)ase64是將二進(jìn)制轉(zhuǎn)碼成可見(jiàn)字符,從而方便我們?cè)谶M(jìn)行http請(qǐng)求時(shí)進(jìn)行傳輸，但是Base64轉(zhuǎn)碼時(shí)會(huì)生成“+”，“/”，“=”符號(hào),這些是被URL進(jìn)行轉(zhuǎn)碼的特殊字符，這樣就會(huì)導(dǎo)致兩方面數(shù)據(jù)不一致,導(dǎo)致我們發(fā)送數(shù)據(jù)請(qǐng)求時(shí),無(wú)法跟后臺(tái)接口正確對(duì)接。

因此我需要在發(fā)送前將“+”，“/”，“=”替換成URL不會(huì)轉(zhuǎn)碼的字符，接收到數(shù)據(jù)后，再將這些字符替換回去，再進(jìn)行解碼。

OC中的處理方式:

#pragma - 將Base64編碼中的"-"，"_"字符串轉(zhuǎn)換成"+"，"/"，字符串長(zhǎng)度余4倍的位補(bǔ)"="
+(NSData*)safeUrlBase64Decode:(NSString*)safeUrlbase64Str
{
    // '-' -> '+'
    // '_' -> '/'
    // 不足4倍長(zhǎng)度，補(bǔ)'='
    NSMutableString * base64Str = [[NSMutableString alloc]initWithString:safeUrlbase64Str];
    base64Str = (NSMutableString * )[base64Str stringByReplacingOccurrencesOfString:@"-" withString:@"+"];
    base64Str = (NSMutableString * )[base64Str stringByReplacingOccurrencesOfString:@"_" withString:@"/"];
    NSInteger mod4 = base64Str.length % 4;
    if(mod4 > 0){
        [base64Str appendString:[@"====" substringToIndex(4-mod4)]];
      }
    NSLog(@"Base64 source str：%@", base64Str);
    return [GTMBase64 decodeData:[base64Str dataUsingEncoding:NSUTF8StringEncoding]];
}

#pragma - Base64編碼中包含有"+,/,="不安全的URL字符串，我們要對(duì)這些字符進(jìn)行轉(zhuǎn)換
+(NSString*)safeUrlBase64Encode:(NSData*)data
{
    // '+' -> '-'
    // '/' -> '_'
    // '=' -> ''
    NSString * base64Str = [GTMBase64 stringByEncodingData:data];
    NSMutableString * safeBase64Str = [[NSMutableString alloc]initWithString:base64Str];
    safeBase64Str = (NSMutableString * )[safeBase64Str stringByReplacingOccurrencesOfString:@"+" withString:@"-"];
    safeBase64Str = (NSMutableString * )[safeBase64Str stringByReplacingOccurrencesOfString:@"/" withString:@"_"];
    safeBase64Str = (NSMutableString * )[safeBase64Str stringByReplacingOccurrencesOfString:@"=" withString:@""];
    NSLog(@"safeBase64編碼：%@", safeBase64Str);
    return safeBase64Str;
}

Android中的處理方式:

//Android話，android.utils.Base64自帶該功能：
Base64.encodeToString(encrypted, Base64.URL_SAFE|Base64.NO_WRAP);
Base64.decode(data, Base64.URL_SAFE);

Java中的處理方式:

public static String safeUrlBase64Encode(byte[] data){
        String encodeBase64 = new BASE64Encoder().encode(data);
        String safeBase64Str = encodeBase64.replace('+', '-');
        safeBase64Str = safeBase64Str.replace('/', '_');
        safeBase64Str = safeBase64Str.replaceAll("=", "");
        return safeBase64Str;
}
public static byte[] safeUrlBase64Decode(final String safeBase64Str){
        String base64Str = safeBase64Str.replace('-', '+');
        base64Str = base64Str.replace('_', '/');
        int mod4 = base64Str.length()%4;
        if(mod4 > 0){
            base64Str = base64Str + "====".substring(mod4);
        }
        return new BASE64Decoder().decodeBuffer(base64Str);
}

PHP中的處理方式:

/**
     * URL base64解碼
     * '-' -> '+'
     * '_' -> '/'
     * 字符串長(zhǎng)度%4的余數(shù)，補(bǔ)'='
     * @param unknown $string
     */
    public static function urlsafe_b64decode($string) {
        $data = str_replace(array('-','_'),array('+','/'),$string);
        $mod4 = strlen($data) % 4;
        if ($mod4) {
            $data .= substr('====', $mod4);
        }
        return base64_decode($data);
    }

    /**
     * URL base64編碼
     * '+' -> '-'
     * '/' -> '_'
     * '=' -> ''
     * @param unknown $string
     */
    function urlsafe_b64encode($string) {
        $data = base64_encode($string);
        $data = str_replace(array('+','/','='),array('-','_',''),$data);
        return $data;
    }