php - 'throw new Exception' 是否需要 exit()？

Question

我正在尝试确定位于 PHP 中 throw new Exception 之后的代码是否仍在执行 - 我已经尝试过了，它似乎没有输出任何内容，但我想知道肯定的。

Answer 1

不，抛出异常后的代码不执行。

在这个代码示例中，我用数字标记了将要执行的行(代码流):

try {
    throw new Exception("caught for demonstration");                    // 1
    // code below an exception inside a try block is never executed
    echo "you won't read this." . PHP_EOL;
} catch (Exception $e) {
    // you may want to react on the Exception here
    echo "exception caught: " . $e->getMessage() . PHP_EOL;             // 2
}    
// execution flow continues here, because Exception above has been caught
echo "yay, lets continue!" . PHP_EOL;                                   // 3
throw new Exception("uncaught for demonstration");                      // 4, end

// execution flow never reaches this point because of the Exception thrown above
// results in "Fatal Error: uncaught Exception ..."
echo "you won't see me, too" . PHP_EOL;

参见 PHP manual on exceptions :

When an exception is thrown, code following the statement will not be executed, and PHP will attempt to find the first matching catch block. If an exception is not caught, a PHP Fatal Error will be issued with an "Uncaught Exception ..." message, unless a handler has been defined with set_exception_handler().