PHP 异常处理类 Exception

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系统默认的异常处理类

/**
* 异常处理类
* zhangming 2014-06-12
* PHP为异常处理提供了内置类－－Exception
* getCode()      返回传递给构造函数的代码
* getMessage()   返回传递给构造函数的消息
* getFile()      返回产生异常的代码文件的完整路径
* getLine()      返回代码文件中产生异常的代码行号
* getTrace()     返回一个包含了产生异常的代码回退路径的数组
* getTraceAsString() 返回与getTrace()方向相同的信息，该信息将被格式化成一个字符串
* __toString()   允许简单地显示一个Exception对象，并且给以上所有方法可以提供的信息
*/

class Exception {
   protected $message = 'Unknown Exception'; //只有继承类和本类能使用
   private $string; //只有本类可以使用
   protected $code = 0;
   protected $file;
   protected $line;
   private $trace;
   private $pervious;

   //公有的初始化类
   public function __construct($message = null, $code = 0, Exception $pervious = null);

   //克隆
   final private function __clone();

   final public function getMessage();
   final public function getCode();
   final public function getFile();
   final public function getLine();
   final public function getTrace();
   final public function getPervious();
   final public function getTraceAsString();

   public function __toString();
}

/**
* define a custome exception class
*/
class MyException extends Exception {
   //初始化对象
   public function __construct($message, $code = 0, Exception $pervious = null) {
       parent::__construct($message, $code, $pervious);
   }
   //对象的自定义字符串表示形式
   public function __toString() {
       return __CLASS__ . ":[{$this->code}]:{$this->message}\n";
   }
   //
   public function customFunction() {
       echo "A custom function for this type of exception\n";
   }
        //test
        public function test() {
                echo "my china!";
        }
}

/**
* create a class test the exception
*/
class TestException {
   //define
   public $var;

   const throw_none = 0;
   const throw_custom = 1;
   const throw_default = 2;

   function __construct($avalue = self::throw_nonw) {
       switch ($avalue){
           case self::throw_custom:
                // throw custom exception
                throw new MyException('1 is an invalid parameter', 5);
                break;

            case self::throw_default:
                // throw default one.
                throw new Exception('2 is not allowed as a parameter', 6);
                break;

            default:
                // No exception, object will be created.
                $this->var = $avalue;
                break;
       }
   }
}

// Example 1
try {
    //$o = new TestException(TestException::throw_custom);
    $o = new TestException(TestException::throw_custom);
} catch (MyException $e) {      // Will be caught
    echo "Caught my exception\n", $e;
    $e->customFunction();
} catch (Exception $e) {        // Skipped
    echo "Caught Default Exception\n", $e;
}

// Continue execution
var_dump($o); // Null
echo "\n\n";

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