perl的替代多行

Question

我有一个文件，它看起来像：

<QUERY name="Secondary"> 
      <SQLStmt>select * from my_tb; 
      </SQLStmt> 
<QUERY name="primary"> 
      <SQLStmt>select * from my_tb; 
      </SQLStmt> 

<QUERY name="last"> 
      <SQLStmt>select * from my_tb; 
      </SQLStmt> 

我需要与其他一些SQLStmnts和查询的名字，我从收到命令行来替代SQLStmnts。

如何使用条件进行匹配和替换？

$qury_nm=shift; 
$sqlstmt=shift; 
undef $/; 
if(/<QUERY name="$qury_nm">(.*)<SQLStmt>(.*)<\SQLStmt>/) 
{ 
    #need help here!! 
    substitute the matched qury_nms SQLStmt wth the $sqlstmt and write it into the same file... 
} 

Answer 1

这里有很长的路要走：

#!/usr/bin/perl 
use 5.10.1; 
use warnings; 
use strict; 

my $qury_nm = 'primary'; 
my $sqlstmt = 'SELECT col1,col2 FROM table2'; 
undef $/; 
my $str = <DATA>; 

$str =~ s!(<QUERY name="$qury_nm">.*?<SQLStmt>).*?(</SQLStmt>)!$1$sqlstmt$2!s; 
say $str; 

__DATA__ 
<QUERY name="Secondary"> 
      <SQLStmt>select * from my_tb; 
      </SQLStmt> 
<QUERY name="primary"> 
      <SQLStmt>select * from my_tb; 
      </SQLStmt> 

<QUERY name="last"> 
      <SQLStmt>select * from my_tb; 
      </SQLStmt> 

输出：

<QUERY name="Secondary"> 
      <SQLStmt>select * from my_tb; 
      </SQLStmt> 
<QUERY name="primary"> 
      <SQLStmt>SELECT col1,col2 FROM table2</SQLStmt> 

<QUERY name="last"> 
      <SQLStmt>select * from my_tb; 
      </SQLStmt> 

Answer 2

XML是不是一个正规的语言。 You should not treat it as such。使用适用于Perl的精美XML解析器之一。一个好的方法可能是使用XML :: Twig。这里是一个教程：http://www.xml.com/pub/a/2001/03/21/xmltwig.html。