My thoughts are messy. It turns out that non-static methods can also be called (transferred) statically. My thoughts are static.
- WBOYOriginal
- 2016-07-06 14:25:161097browse
My thoughts are messy. It turns out that non-static methods can also be called statically (transferred). My thoughts are static
1. Non-static methods can be called statically in PHP Static method?
Today I was asked whether I can use the className::methodName() method in PHP to call a method that is not declared Static. In my mind, I seem to have seen this usage before, but I'm a little unsure. As we all know, in manuals or tutorials, methods are divided into static methods and non-static methods. Usually the methods we call statically must be static methods.
What happens if we call a non-static method? Do a test first.<?php<code><?php<br>
class test{<br>
function test(){<br>
echo 'it works';<br>
}<br>
}<br>
test::test();
class test{
function test(){
echo 'it works';
}
}Fatal error:
Non-static method test::test() cannot be called statically in
/home/×××/test.php<br>
on line 7 Call Stack: 0.0002 332548 1. {main}()
/home/×××/test.php:0
test::test();
Execute the following and the error returned is as follows
Fatal error:
Non-static method test::test() cannot be called statically in
/home/×××/test.php<span>
on line 7 Call Stack: 0.0002 332548 1. {main}()
/home/×××/test.php:0</span>
At this time, you may think that calling non-static methods statically is not feasible, but in fact, it is too early to draw a conclusion, because the test() method is quite special. It has the same name as the class and is a constructor method.
<?php<br>
class test{<br>
function test(){<br>
echo 'it works';<br>
}<br>
function test2(){<br>
echo 'it works too';<br>
}<br>
}<br>
test::test2();
Let’s continue testing. it works too<?php<strong>
class test{</strong>
function test(){<br>
echo 'it works';
}
function test2(){<?php<br>
class test{<br>
static function test(){<br>
echo 'it works';<br>
}<br>
}<br>
test::test();
echo 'it works too';
}
}Fatal error: Constructor test::test() cannot be static in
/home/xxx/test.php on line 9
test::test2();
Execution result:
This shows that it is possible to statically call non-static methods, but it is not possible to statically call constructors . In order to verify this conclusion, I did the following test:
Cannot make a static reference to the non-static method
showString() from the type HelloWorldApp<?php<br>
class test{
static function test(){
} } test::test(); The execution result is as follows: Constructors cannot be declared static, so the above inference is correct.
But this result is indeed very special, because maybeonly PHP can statically call non-static methods. I did an experiment with Java. If you statically call a non-static method, the following error will be reported:
I have not tried other languages one by one, but this is enough to illustrate the special features of PHP. I have not found any relevant explanation as to why PHP has such a situation.
<?php<br>
class test{function test2(){}}
for($k=0; $k<10000; $k )
{
test::test2();
}
2. Should static calls to non-static methods be applied? <?php<br>
class test{static function test2(){}}
for($k=0; $k<10000; $k )
{
test::test2();
}
Can we use this method instead of the static method? First of all, from the perspective of code readability, statically calling non-static methods is of course not recommended
<?php
class test{function test2(){}}
for($k=0; $k<10000; $k )
{
test::test2();
}
The execution time of the above code here is 18 to 28 milliseconds. Let's test the standard writing method. <?php
class test{static function test2(){}}
for($k=0; $k<10000; $k )
{
test::test2();
}
The above code execution time is between 5 and 10 milliseconds. From this point of view, the efficiency of statically calling non-static methods is much lower than standard static method calls, so statically calling non-static methods is not recommended in terms of efficiency. .