PHP在循环内外实例化类在占用内存上有很大的区别
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关于php类的实例化和内存的关系,可以这么说:只要有一个new 关键字就是创建一个对象,创建一个对象就是在内存中分配了一个空间 ,那么OK,看代码。
01.
<?php
02.
class
ABC{
03.
public
$numBox
=
array
();
04.
public
function
ddd(){
05.
for
(
$i
=1;
$i
<=600;
$i
++){
06.
$this
->numBox[] = mt_rand(1,1000000);
07.
}
08.
echo
'Now memory_get_usage: '
.memory_get_usage().
'<br />'
;
09.
}
10.
11.
}
12.
$instance
=
new
ABC();
13.
for
(
$i
=0;
$i
< 50 ;
$i
++){
14.
$instance
->ddd();
15.
}
16.
?>
这是上面的代码在我的机器上面运行的结果:
Now memory_get_usage: 424312
Now memory_get_usage: 476408
Now memory_get_usage: 524408
Now memory_get_usage: 580608
Now memory_get_usage: 628608
Now memory_get_usage: 676608
Now memory_get_usage: 740992
Now memory_get_usage: 789000
Now memory_get_usage: 837000
Now memory_get_usage: 885000
Now memory_get_usage: 933000
Now memory_get_usage: 981000
Now memory_get_usage: 1029000
Now memory_get_usage: 1109768
Now memory_get_usage: 1157768
Now memory_get_usage: 1205768
Now memory_get_usage: 1253768
Now memory_get_usage: 1301768
Now memory_get_usage: 1349768
Now memory_get_usage: 1397768
Now memory_get_usage: 1445768
Now memory_get_usage: 1493768
01.
<?php
02.
class
ABC{
03.
public
$numBox
=
array
();
04.
public
function
ddd(){
05.
for
(
$i
=1;
$i
<=600;
$i
++){
06.
$this
->numBox[] = mt_rand(1,1000000);
07.
}
08.
echo
'Now memory_get_usage: '
.memory_get_usage().
'<br />'
;
09.
}
10.
11.
}
12.
13.
for
(
$i
=0;
$i
< 50 ;
$i
++){
14.
$instance
=
new
ABC();
15.
$instance
->ddd();
16.
}
17.
?>
这个是上面的代码运行的结果:
Now memory_get_usage: 424552
Now memory_get_usage: 424536
Now memory_get_usage: 424536
Now memory_get_usage: 424536
Now memory_get_usage: 424536
Now memory_get_usage: 424536
Now memory_get_usage: 424536
Now memory_get_usage: 424536
Now memory_get_usage: 424536
Now memory_get_usage: 424536
Now memory_get_usage: 424536
Now memory_get_usage: 424536
Now memory_get_usage: 424536
Now memory_get_usage: 424536
Now memory_get_usage: 424536
Now memory_get_usage: 424536
Now memory_get_usage: 424536
Now memory_get_usage: 424536
Now memory_get_usage: 424536
Now memory_get_usage: 424536
Now memory_get_usage: 424536
Now memory_get_usage: 424536
Now memory_get_usage: 424536
Now memory_get_usage: 424536
Now memory_get_usage: 424536
OK,其实,只要有一个new 关键字就是创建一个对象,创建一个对象就是在内存中分配了一个空间,每次重新分配内存一定是要占用更多的内存的,所以,我们要对的类的实例化要注意,这样也就是为什么要使用单实例设计模式,因为这样可以节约内存。