您应该使用正则表达式,可能使用NSRegularExpression类。
这是一个完全符合您要求的示例(来自此处):
- (NSString *)stripOutHttp:(NSString *)httpLine
{
// Setup an NSError object to catch any failures
NSError *error = NULL;
// create the NSRegularExpression object and initialize it with a pattern
// the pattern will match any http or https url, with option case insensitive
NSRegularExpression *regex = [NSRegularExpression
regularExpressionWithPattern:@"https?://([-\\w\\.]+)+(:\\d+)?(/([\\w/_\\.]*(\\?\\S+)?)?)?"
options:NSRegularExpressionCaseInsensitive
error:&error];
// create an NSRange object using our regex object for the first match in the string httpline
NSRange rangeOfFirstMatch = [regex rangeOfFirstMatchInString:httpLine
options:0
range:NSMakeRange(0, [httpLine length])];
// check that our NSRange object is not equal to range of NSNotFound
if (!NSEqualRanges(rangeOfFirstMatch, NSMakeRange(NSNotFound, 0)))
{
// Since we know that we found a match, get the substring from the parent
// string by using our NSRange object
NSString *substringForFirstMatch = [httpLine substringWithRange:rangeOfFirstMatch];
NSLog(@"Extracted URL: %@",substringForFirstMatch);
// return the matching string
return substringForFirstMatch;
}
return NULL;
}