Perl 学习手札之十四： Module

最新推荐文章于 2025-08-15 14:54:53 发布

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最新推荐文章于 2025-08-15 14:54:53 发布

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文章标签： shell

原文链接：http://www.cnblogs.com/hanleilei/archive/2012/03/17/2403329.html

本文介绍了Perl编程中模块的使用，包括模块的创建、初始化、调用及安装方法。通过两个具体的例子展示了如何将代码封装为模块，以及如何在不同脚本中复用这些模块。此外，还介绍了模块的注释编写方法和依赖关系处理。

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Perl 学习手札之十四： Module

Modules are collections of Perl code for use with different scripts

Modules can be object-oriented or procedural

Modules can contain code and/or data

Object-oriented vs procedural modules

Most modules are object-oriented.

object-oriented code has these properties.

-Dynamic: the object determines what code to invoke

-Encapsulated: the object contains all the code and data it needs

-Abstraction: the details may be hidden from the user

-Inheritance: One object may inherit properties from another

Procedural code has these properties:

-simplicity: small subroutines may be coded quickly and easily

-Modularity: Functionalities may be used and resused

-Linearity: code is clear and readable

建立一个module：Example.pm

# Example.pm
#  Example perl module
#

package Example;
use strict;
use warnings;
use IO::File;

our $VERSION = " 0.1 ";

sub new{
     my $class = shift;
     my $self = {};
     bless( $self, $class);
     return $self;
}

sub copyfile
{
     my ( $self, $origfile, $newfile ) = @_;
     my $bufsize = 1024 * 1024;

     my $origfh = IO::File->new( $origfile, ' r ') or die( " cannot open $origfile ($!) ");
     my $newfh = IO::File->new( $newfile, ' w ') or die( " cannot open $newfile ($!) ");

     $origfh-> binmode( " :raw ");
     $newfh-> binmode( " :raw ");

     my $buf = '';
     while( $origfh-> read( $buf, $bufsize ) ) {
         $newfh-> print( $buf );
    }
     return 1;
}

1;

这个就是前面的复制文件的代码，现在写到模块里面，注意package关键字。

下面就是调用模块的代码：

creating.pl

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

main( @ARGV);

sub main
{
     my $o = Example->new();
     $o->copyfile( " olives.jpg ", " newfile.jpg ");
    message( " Done. ");
}

sub message
{
     my $m = shift or return;
     print( " $m\n ");
}

sub error
{
     my $e = shift || ' unkown error ';
     print( " $0: $e\n ");
     exit 0;
}

如前面所示：用了module，代码变得非常简洁，并且可以复用。

下面写一个模块：

Artist.pm

# Artist.pm
#
# Description goes here
# by Your Name
#

package Artist;
use strict;
use warnings;

our $VERSION = " 0.1 ";

sub new
{
     my $class = shift;
     my $self  = {};

     bless( $self, $class );
     return $self;
}

sub name
{
     my ( $self, $name) = @_;
     $self->{name}= $name if defined $name;
     return $self->{name};
}

1;

__END__

=head1 NAME

Template - Description goes here

=head1 SYNOPSIS

     use Template
     my $o = Template->new;

=head1 METHODS

=over 4

=item B<new>

Constructs a new Template object.

Returns a blessed Template object reference.

=item B<method>

Describe the method here

=back

=head1 AUTHOR

Written by Your Name

=head1 HISTORY

    Version history here.

=cut

在__END__后面的部分是模块的注释。可以根据这个例子学习模块的编写

然后调用模块：

oodata.pl

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

main( @ARGV);

sub main
{
     my $o = Artist->new;
     my $o2=Artist->new;
     $o->name( " Jimi Hendrix ");
     $o2->name( " Miles Davis ");
    message( $o->name);
    message( $o2->name);
    message( $Artist::VERSION);
    message( $o->VERSION);
}

sub message
{
     my $m = shift or return;
     print( " $m\n ");
}

sub error
{
     my $e = shift || ' unkown error ';
     print( " $0: $e\n ");
     exit 0;
}

可以有几种方式初始化模块，然后调用模块。

安装模块

1. 可以在unix-like系统里面采用下面的方式：

1）：在命令行里面输入：sudo cpan 模块名

2）：在命令行里面输入perl -MCPAN -e shell，然后进入CPAN>模式，输入install 模块名，完成安装。

3) ：在search.cpan.org里面查找模块，下载相应的tar.gz安装包，然后依次输入：

perl MAKEFILE.pl

make

make test

make install

然后完成安装。

2. 可以在windows系统下面采用下面的方式：