php——13-include 和 require 文件引入

版权声明：未经同意，不得随意转载转载 https://blog.csdn.net/lucky541788/article/details/82936374

cc.php 文件

<?php
class name
{
    public $s1 = 0;
    public $s2 = 1;

    public function __construct()
    {
        echo 'hello world!';
    }

    public function s1()
    {
        echo $this->s1;
    }

    public function s2()
    {
        echo $this->s2;
    }
}

$name = new name();//hello world!

include 和 require

include

<?php
include ('cc.php');//hello world!

echo "<br>";
$name->s1();//0
$name->s2();//1
echo "<br>";
echo "我在 cc2.php 中引用了 cc.php 并调用了对象方法";

require

<?php
require ('cc.php');//hello world!

echo "<br>";
$name->s1();//0
$name->s2();//1
echo "<br>";
echo "我在 cc2.php 中引用了 cc.php 并调用了对象方法";

两者区别

include在文件引入出错，之后代码会继续运行

<?php
include ('error');//故意引入错误文件
echo "<br>";
echo "<h1 style='color: #0ab4f7'>hello world！</h1>""; //hello world!会继续显示

require在文件引入出错，之后代码会停止运行

<?php
require ('error');//故意引入错误文件
echo "<br>";
echo "<h1 style='color: #0ab4f7'>hello world！</h1>""; //hello world!不会显示

include_once 和 require_once

include_once

因为 include 重复引入会报错，如下：

<?php
include ('cc.php');
include ('cc.php');
include ('cc.php');//hello world!

echo "<br>";
$name->s1();
$name->s2();
echo "<br>";
echo "我在 cc2.php 中引用了 cc.php 并调用了对象方法";

所以引入了 include_once

<?php
include_once ('cc.php');
include_once ('cc.php');
include_once ('cc.php');//hello world!

echo "<br>";
$name->s1();//0
$name->s2();//1
echo "<br>";
echo "我在 cc2.php 中引用了 cc.php 并调用了对象方法";

require_once

原因同上，代码：

<?php
require_once ('cc.php');
require_once ('cc.php');
require_once ('cc.php');//hello world!

echo "<br>";
$name->s1();//0
$name->s2();//1
echo "<br>";
echo "我在 cc2.php 中引用了 cc.php 并调用了对象方法";