- (NSString *)getParameter:(NSString *)parameter urlStr:(NSString *)url {        NSError *error;        if (!url) {                return@"";            }        NSString *regTags = [[NSString alloc] initWithFormat:@"(^|&|\\?)+%@=+([^&]*)(&|$)",parameter];        NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:regTags options:NSRegularExpressionCaseInsensitive error:&error];        NSArray *matches = [regex matchesInString:url options:0 range:NSMakeRange(0, [url length])];        for (NSTextCheckingResult *match in matches) {                NSString *tagValue = http://www.mamicode.com/[url substringWithRange:[match rangeAtIndex:2]]; //分组2所对应的串                return tagValue;            }        return@"";    }

- (NSString *)deleteParameter:(NSString *)parameter WithOriginUrl:(NSString *)originUrl {    NSString *finalStr = [NSString string];        NSMutableString * mutStr = [NSMutableString stringWithString:originUrl];        NSArray *strArray = [mutStr componentsSeparatedByString:parameter];        NSMutableString *firstStr = [strArray objectAtIndex:0];        NSMutableString *lastStr = [strArray lastObject];        NSRange characterRange = [lastStr rangeOfString:@"&"];    if (characterRange.location !=NSNotFound) {        NSArray *lastArray = [lastStr componentsSeparatedByString:@"&"];                NSMutableArray *mutArray = [NSMutableArray arrayWithArray:lastArray];                [mutArray removeObjectAtIndex:0];                NSString *modifiedStr = [mutArray componentsJoinedByString:@"&"];                finalStr = [[strArray objectAtIndex:0]stringByAppendingString:modifiedStr];            } else {                //以‘?‘、‘&‘结尾        finalStr = [firstStr substringToIndex:[firstStr length] -1];            }    return finalStr;    }