先編輯command.php文件
echo 'hello'.PHP_EOL;
然后編輯console.php文件
for($i=1;$i<=3;++$i){
require 'command1.php';
}
原本想要包含並執行這個echo，沒想到寫錯了文件名，如果是require，會報出這樣的錯誤：
Warning: require(command1.php): failed to open stream: No such file or directory in console.php on line 4 Fatal error: require(): Failed opening required 'command1.php' (include_path='.') in console.php on line 4 PHP Warning: require(command1.php): failed to open stream: No such file or directory in console.php on line 4 PHP Fatal error: require(): Failed opening required 'command1.php' (include_path='.') in console.php on line 4
如果把require改為include
for($i=1;$i<=3;++$i){
include 'command1.php';
}
會報出這樣的錯誤：
Warning: include(command1.php): failed to open stream: No such file or directory in console.php on line 4 Warning: include(): Failed opening 'command1.php' for inclusion (include_path='.') in console.php on line 4 Warning: include(command1.php): failed to open stream: No such file or directory in console.php on line 4 Warning: include(): Failed opening 'command1.php' for inclusion (include_path='.') in console.php on line 4 Warning: include(command1.php): failed to open stream: No such file or directory in console.php on line 4 Warning: include(): Failed opening 'command1.php' for inclusion (include_path='.') in console.php on line 4 PHP Warning: include(command1.php): failed to open stream: No such file or directory in console.php on line 4 PHP Warning: include(): Failed opening 'command1.php' for inclusion (include_path='.') in console.php on line 4 PHP Warning: include(command1.php): failed to open stream: No such file or directory in console.php on line 4 PHP Warning: include(): Failed opening 'command1.php' for inclusion (include_path='.') in console.php on line 4 PHP Warning: include(command1.php): failed to open stream: No such file or directory in console.php on line 4 PHP Warning: include(): Failed opening 'command1.php' for inclusion (include_path='.') in console.php on line 4
如果使用require_once或者include_once，只要包含路徑正確，那么循環只執行一次。
總結：
使用require，如果文件沒有包含成功，就會報出一個fatal error，整個程序就中止了。
使用include，如果文件沒有包含成功，就會報出一個普通的warning，之后的代碼仍會執行。
如果你的Web程序使用了MVC這種對文件包含強依賴的設計方法，請使用require_once。