php错误及异常捕捉

原文:php错误及异常捕捉

在实际开发中，错误及异常捕捉仅仅靠try{}catch()是远远不够的。

所以引用以下几中函数。

a)   set_error_handler

一般用于捕捉  E_NOTICE 、E_USER_ERROR、E_USER_WARNING、E_USER_NOTICE

不能捕捉：

E_ERROR, E_PARSE, E_CORE_ERROR, E_CORE_WARNING, E_COMPILE_ERROR and E_COMPILE_WARNING。

一般与trigger_error("...", E_USER_ERROR)，配合使用。

<?php
// we will do our own error handling
error_reporting(0);
function userErrorHandler($errno, $errmsg, $filename, $linenum, $vars)
{
    // timestamp for the error entry
	$dt = date("Y-m-d H:i:s (T)");
	// define an assoc array of error string
	// in reality the only entries we should
	// consider are E_WARNING, E_NOTICE, E_USER_ERROR,
	// E_USER_WARNING and E_USER_NOTICE
	$errortype = array (
		E_ERROR              => ‘Error‘,
		E_WARNING            => ‘Warning‘,
		E_PARSE              => ‘Parsing Error‘,
		E_NOTICE             => ‘Notice‘,
		E_CORE_ERROR         => ‘Core Error‘,
		E_CORE_WARNING       => ‘Core Warning‘,
		E_COMPILE_ERROR      => ‘Compile Error‘,
		E_COMPILE_WARNING    => ‘Compile Warning‘,
		E_USER_ERROR         => ‘User Error‘,
		E_USER_WARNING       => ‘User Warning‘,
		E_USER_NOTICE        => ‘User Notice‘,
		E_STRICT             => ‘Runtime Notice‘,
		E_RECOVERABLE_ERROR  => ‘Catchable Fatal Error‘
	);
	// set of errors for which a var trace will be saved
	$user_errors = array(E_USER_ERROR, E_USER_WARNING, E_USER_NOTICE);
	$err = "<errorentry>\n";
	$err .= "\t<datetime>" . $dt . "</datetime>\n";
	$err .= "\t<errornum>" . $errno . "</errornum>\n";
	$err .= "\t<errortype>" . $errortype[$errno] . "</errortype>\n";
	$err .= "\t<errormsg>" . $errmsg . "</errormsg>\n";
	$err .= "\t<scriptname>" . $filename . "</scriptname>\n";
	$err .= "\t<scriptlinenum>" . $linenum . "</scriptlinenum>\n";
	if (in_array($errno, $user_errors)) {
		$err .= "\t<vartrace>" . wddx_serialize_value($vars, "Variables") . "</vartrace>\n";
	}
	$err .= "</errorentry>\n\n";
	echo $err;
}
function distance($vect1, $vect2) {
	if (!is_array($vect1) || !is_array($vect2)) {
		trigger_error("Incorrect parameters, arrays expected", E_USER_ERROR);
		return NULL;
	}
	if (count($vect1) != count($vect2)) {
		trigger_error("Vectors need to be of the same size", E_USER_ERROR);
		return NULL;
	}
	for ($i=0; $i<count($vect1); $i++) {
		$c1 = $vect1[$i]; $c2 = $vect2[$i];
		$d = 0.0;
		if (!is_numeric($c1)) {
		trigger_error("Coordinate $i in vector 1 is not a number, using zero",E_USER_WARNING);
		$c1 = 0.0;
	}
	if (!is_numeric($c2)) {
		trigger_error("Coordinate $i in vector 2 is not a number, using zero",E_USER_WARNING);
		$c2 = 0.0;
	}
	$d += $c2*$c2 - $c1*$c1;
	}
	return sqrt($d);
}

$old_error_handle = set_error_handler("userErrorHandler");
$t = I_AM_NOT_DEFINED;	//generates a warning

// define some "vectors"
$a = array(2, 3, "foo");
$b = array(5.5, 4.3, -1.6);
$c = array(1, -3);

//generate a user error
$t1 = distance($c,$b);

// generate another user error
$t2 = distance($b, "i am not an array") . "\n";

// generate a warning
$t3 = distance($a, $b) . "\n";
?>

b)   set_exception_handler

设置默认的异常处理程序，用于没有用 try/catch 块来捕获的异常。 在 exception_handler 调用后异常会中止。

与throw new Exception(‘Uncaught Exception occurred‘)，连用。

<?php
// we will do our own error handling
error_reporting(0);
function exceptHandle($errno, $errmsg, $filename, $linenum, $vars)
{
    // timestamp for the error entry
	$dt = date("Y-m-d H:i:s (T)");
	// define an assoc array of error string
	// in reality the only entries we should
	// consider are E_WARNING, E_NOTICE, E_USER_ERROR,
	// E_USER_WARNING and E_USER_NOTICE
	$errortype = array (
		E_ERROR              => ‘Error‘,
		E_WARNING            => ‘Warning‘,
		E_PARSE              => ‘Parsing Error‘,
		E_NOTICE             => ‘Notice‘,
		E_CORE_ERROR         => ‘Core Error‘,
		E_CORE_WARNING       => ‘Core Warning‘,
		E_COMPILE_ERROR      => ‘Compile Error‘,
		E_COMPILE_WARNING    => ‘Compile Warning‘,
		E_USER_ERROR         => ‘User Error‘,
		E_USER_WARNING       => ‘User Warning‘,
		E_USER_NOTICE        => ‘User Notice‘,
		E_STRICT             => ‘Runtime Notice‘,
		E_RECOVERABLE_ERROR  => ‘Catchable Fatal Error‘
	);
	// set of errors for which a var trace will be saved
	$err = "<errorentry>\n";
	$err .= "\t<datetime>" . $dt . "</datetime>\n";
	$err .= "\t<errornum>" . $errno . "</errornum>\n";
	$err .= "\t<errortype>" . $errortype[$errno] . "</errortype>\n";
	$err .= "\t<errormsg>" . $errmsg . "</errormsg>\n";
	$err .= "\t<scriptname>" . $filename . "</scriptname>\n";
	$err .= "\t<scriptlinenum>" . $linenum . "</scriptlinenum>\n";
	if (1) {
		$err .= "\t<vartrace>" . wddx_serialize_value($vars, "Variables") . "</vartrace>\n";
	}
	$err .= "</errorentry>\n\n";
	echo $err;
}
$old_except_handle = set_exception_handler("exceptHandle");
//$t = I_AM_NOT_DEFINED;	//generates a warning
$a;
throw new Exception(‘Uncaught Exception occurred‘);
?>

c)   register_shutdown_function

执行机制是：php把要调用的函数调入内存。当页面所有ＰＨＰ语句都执行完成时，再调用此函数。

一般与trigger_error("...", E_USER_ERROR)，配合使用。

<?php
error_reporting(0);
date_default_timezone_set(‘Asia/Shanghai‘);
register_shutdown_function(‘my_exception_handler‘);

$t = I_AM_NOT_DEFINED;	//generates a warning
trigger_error("Vectors need to be of the same size", E_USER_ERROR);     

function my_exception_handler()
{
    if($e = error_get_last()) {
    //$e[‘type‘]对应php_error常量
    $message = ‘‘;
    $message .= "出错信息:\t".$e[‘message‘]."\n\n";
    $message .= "出错文件:\t".$e[‘file‘]."\n\n";
    $message .= "出错行数:\t".$e[‘line‘]."\n\n";
    $message .= "\t\t请工程师检查出现程序".$e[‘file‘]."出现错误的原因\n";
    $message .= "\t\t希望能您早点解决故障出现的原因<br/>";
	echo $message;
    //sendemail to
    }
}
?>

c) restore_error_handler()函数

定义和用法 restore_error_handler() 函数恢复之前的错误处理程序，该程序是由 set_error_handler() 函数改变的。

该函数永远返回 true。

是 set_error_handler()的反函数。