类方法：传递给类方法的第一个参数是隐藏的，是->符号左边的字符串（即类名）。
实例方法：传递给实例方法的第一个参数也是隐藏的，是->符号左边的字符串（一个引用或叫做一个对象）。
最常用的类方法是：constructor function（构造函数）。
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[root@dou shili]# cat House.pm
#!/usr/bin/perl
package House;
use warnings;
use strict;
sub new {
??????? my $class = shift; #Constructor method
??????? my $ref = { }; #Create a reference
??????? bless($ref,$class); #Create the object with bless function
??????? return $ref; #Return a reference to the object
}
sub set_data {
??????? my $self = shift; #Access or instance methods
??????? $self->{key} = shift; #Assign or store the object's attributes
}
sub get_data {
??????? my $self = shift;
??????? return $self->{key}; #Get or fetch the object's attributes
}
1;
[root@dou shili]# clear
[root@dou shili]# cat House.pm
#!/usr/bin/perl
package House;
use warnings;
use strict;
sub new {
??????? my $class = shift; #Constructor method
??????? my $ref = { }; #Create a reference
??????? bless($ref,$class); #Create the object with bless function
??????? return $ref; #Return a reference to the object
}
sub set_data {
??????? my $self = shift; #Access or instance methods
??????? $self->{key} = shift; #Assign or store the object's attributes
}
sub get_data {
??????? my $self = shift;
??????? return $self->{key}; #Get or fetch the object's attributes
}
1;
[root@dou shili]# cat useHouse.pl
#!/usr/bin/perl -w
use strict;
use House;
my $arg1 = "hello";
my $arg2 = "stillhello";
my $obj1 = House->new; # Create the object;a reference is returned
my $obj2 = House->new;? # Create another house object.
$obj1->set_data($arg1);??? # Store or assign data to the object
my $result1 = $obj1->get_data;??? # Fetch data from the object
print "The result1 is $result1n";
$obj2->set_data($arg2);??? # Store or assign data to the object
my $result2 = $obj2->get_data;??? # Fetch data from the object
print "The result2 is $result2n";
[root@dou shili]# perl useHouse.pl
The result1 is hello
The result2 is stillhello
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在引用中给对象添加属性：并使用ref判断对象属于哪个package。
[root@dou shili]# cat Hh.pm
#!/usr/bin/perl
package Hh;
use warnings;
use strict;
sub new {
??????? my $class = shift;
??????? my $ref = { owner => shift,
??????????????????? country => shift,
????????????????? };
??????? bless($ref,$class);
??????? return $ref;
}
1;
[root@dou shili]# cat useHh.pl
#!/usr/bin/perl -w
use strict;
use Hh;
my $arg1 = "aobama"; my $arg2 = "America"; my $ref = Hh->new($arg1,$arg2); my $owner = $ref->{owner}; my $country = $ref->{country}; print "The owner of the house is $ownern"; print "The location of the house is $countryn"; print "The object $ref belongs to package ref($ref)n"; [root@dou shili]# perl useHh.pl The owner of the house is aobama The location of the house is America The object $ref belongs to package ref(Hh=HASH(0x1344e2a0)) 最后一句显示对象属于package Hh。
