PHP中include和require的区别实例分析

先编辑command.PHP文件

rush:PHP;gutter:true;"> echo 'hello'.PHP_EOL;

然后编辑console.PHP文件

rush:PHP;gutter:true;"> for($i=1;$i<=3;++$i){ require 'command1.PHP'; }

原本想要包含并执行这个echo，没想到写错了文件名，如果是require，会报出这样的错误：

rush:bash;gutter:true;"> 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改为include

rush:PHP;gutter:true;"> for($i=1;$i<=3;++$i){ include 'command1.PHP'; }

会报出这样的错误：

rush:bash;gutter:true;"> 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，只要包含路径正确，那么循环只执行一次。

总结：

使用require，如果文件没有包含成功，就会报出一个Fatal error，整个程序就中止了。

使用include，如果文件没有包含成功，就会报出一个普通的warning，之后的代码仍会执行。

如果你的Web程序使用了MVC这种对文件包含强依赖的设计方法，请使用require_once。

原文地址：https://www.jb51.cc/php/17490.html