NSURL query中获取参数字典

【PS：copy from Web to Memo】

- (NSDictionary*)dictionaryFromQuery:(NSString*)query
{
    NSCharacterSet* delimiterSet = [NSCharacterSet characterSetWithCharactersInString:@"&"];
    NSMutableDictionary* pairs = [NSMutableDictionary dictionary];
    NSScanner* scanner = [[NSScanner alloc] initWithString:query];
    while (![scanner isAtEnd]) {
        NSString* pairString = nil;
        [scanner scanUpToCharactersFromSet:delimiterSet intoString:&pairString];
        [scanner scanCharactersFromSet:delimiterSet intoString:NULL];
        NSArray* kvPair = [pairString componentsSeparatedByString:@"="];
        if (kvPair.count == 2) {
            NSString* key = [[kvPair objectAtIndex:0] stringByRemovingPercentEncoding];
            NSString* value = [[kvPair objectAtIndex:1] stringByRemovingPercentEncoding];
            [pairs setObject:value forKey:key];
        }
    }
    
    return [NSDictionary dictionaryWithDictionary:pairs];
}