iOS开发笔记之普通字符串与十六进制字符串的相互转换

// 普通字符串转换为十六进制的字符串
- (NSString *)hexStringFromString:(NSString *)string {
    NSData *myD = [string dataUsingEncoding:NSUTF8StringEncoding];
    Byte *bytes = (Byte *)[myD bytes];
    NSString *hexStr=@"";
    for(int i=0;i<[myD length];i++) {
        NSString *newHexStr = [NSString stringWithFormat:@"%x",bytes[i]&0xff]; //16进制数
        if([newHexStr length]==1) {
            hexStr = [NSString stringWithFormat:@"%@0%@",hexStr,newHexStr];
        } else {
            hexStr = [NSString stringWithFormat:@"%@%@",hexStr,newHexStr];
        }
    }
    return hexStr;
}

// 十六进制转换为普通字符串
- (NSString *)stringFromHexString:(NSString *)hexString {
    char *myBuffer = (char *)malloc((int)[hexString length] / 2 + 1);
    bzero(myBuffer, [hexString length] / 2 + 1);
    for (int i = 0; i < [hexString length] - 1; i += 2) {
        unsigned int anInt;
        NSString * hexCharStr = [hexString substringWithRange:NSMakeRange(i, 2)];
        NSScanner * scanner = [[NSScanner alloc] initWithString:hexCharStr];
        [scanner scanHexInt:&anInt];
        myBuffer[i / 2] = (char)anInt;
    }
    NSString *unicodeString = [NSString stringWithCString:myBuffer encoding:4];

    return unicodeString;
}