PHP:附加到抛出的异常消息

Question

以下功能为例,说明我想做的事情:

public function save() {
    $this->connect('wb');
    try {
        if(!$this->lock())
            throw new Exception("Unable to acquire configuration locks");
        if (!$backup = $this->backup())
            throw new Exception("Failed to create configuration backup");
        try {
            if(!fwrite($this->_pointer, $this->dump("string")));
                throw new Exception("Error occured while writing to configuration");
            $this->unlock();
            $this->disconnect();
        } catch (Exception $e) {
            if(rename ($backup, $this->_file))
                $e .= PHP_EOL."Successfully restored configuration from backup";
            else
                $e .= PHP_EOL."Failed to restore configuration from backup";
            $this->unlock();
            $this->disconnect();
            throw $e;
        }
    } catch (Exception $e) {
        echo PHP_EOL, $e->getMessage();
    }
}

我有嵌套try()和catch()声明.从最内层抛出一个异常并被捕获,然后我执行一些函数并抛出另一个异常.注意我写的地方$e .=,我明白这是不正确的语法.我想要做的是将字符串追加到异常中$e->getMessage().

我该怎么做呢？

Answer 1

创建自己的异常类并创建用于将字符串附加到消息的方法.

<?php
class SuperException extends Exception
{
    public function AppendToMessage($msg)
    {
        // $this->message is inherited from Exception class,
        // where it is protected field (member) of the class
        $this->message .= $msg;
    }
}
?>