Question

遇到else条件（无效的url）后，循环终止，不再处理其他URL。 2.即使节点在xpath中失败，它也不会在屏幕或文件中打印。我想在文件和屏幕中打印（节点异常）

use LWP::Simple;
use File::Compare;
use HTML::TreeBuilder::XPath;
use LWP::UserAgent;
use Win32::Console::ANSI;
use Term::ANSIColor;


sub crawl_content{
    {
        open(FILE, "C:/Users/jeyakuma/Desktop/input/input.txt");  
        {
            while(<FILE>){                   
                chomp;
                $url=$_;
                foreach ($url){
                    $domain) = $url =~ m|www.([A-Z a-z 0-9]+.{3}).|x;
                }

                do 'C:/Users/jeyakuma/Desktop/perl/mainsub.pl';
                &domain_check();

                my $ua = LWP::UserAgent->new( agent => "Mozilla/5.0" );
                my $req = HTTP::Request->new( GET => "$url" );
                my $res = $ua->request($req);



                if ( $res->is_success ){

                    print "working on $domain\n";

                    binmode ":utf8";
                    my $xp = HTML::TreeBuilder::XPath->new_from_url($url);
                    my @node = $xp->findnodes_as_string("$xpath") or print "couldn't find the node\n" ;

                    open HTML, '>:encoding(cp1252)',"C:/Users/jeyakuma/Desktop/ project/data_$date/$site.html";

                    foreach(<@node>){
                        print HTML @node;
                        close HTML ;
                    }
               }
                else{  
                         print color("green"), "$domain   Invalid url\n", color("reset") and open FILE,">C:/Users/jeyakuma/Desktop/log.txt";  print FILE " $domain Invalid URL";

                }
            } 
        }
    }
}
do 'C:/Users/jeyakuma/Desktop/perl/comparefinal.pl';
compare_result();
}

Answer 1

else条件重新打开FILE以写入另一个文件。因此，在while (<FILE>)循环的下一次迭代中，Perl将尝试从FILE读取并失败（因为它现在只能用于写入而不是读取），并且循环将结束。您需要在FILE条件中使用else以外的名称。

程序在perl中的else条件之后终止

1 个答案: