php日志类

<?php
require 'log.php';
$logHandler= new CLogFileHandler(date('Y-m-d').'.log');//文件路径
$log = Log::Init($logHandler, 15);
$log->DEBUG('123');
</code>
<code>
<?php
//以下为日志

interface ILogHandler
{
    public function write($msg);

}

class CLogFileHandler implements ILogHandler
{
    private $handle = null;

    public function __construct($file = '')
    {
        $this->handle = fopen($file,'a');
    }

    public function write($msg)
    {
        fwrite($this->handle, $msg, 4096);
    }

    public function __destruct()
    {
        fclose($this->handle);
    }
}

class Log
{
    private $handler = null;
    private $level = 15;

    private static $instance = null;

    private function __construct(){}

    private function __clone(){}

    public static function Init($handler = null,$level = 15)
    {
        if(!self::$instance instanceof self)
        {
            self::$instance = new self();
            self::$instance->__setHandle($handler);
            self::$instance->__setLevel($level);
        }
        return self::$instance;
    }

    private function __setHandle($handler){
        $this->handler = $handler;
    }

    private function __setLevel($level)
    {
        $this->level = $level;
    }

    public static function DEBUG($msg)
    {
        self::$instance->write(1, $msg);
    }

    public static function WARN($msg)
    {
        self::$instance->write(4, $msg);
    }

    public static function ERROR($msg)
    {
        $debugInfo = debug_backtrace();
        $stack = "[";
        foreach($debugInfo as $key => $val){
            if(array_key_exists("file", $val)){
                $stack .= ",file:" . $val["file"];
            }
            if(array_key_exists("line", $val)){
                $stack .= ",line:" . $val["line"];
            }
            if(array_key_exists("function", $val)){
                $stack .= ",function:" . $val["function"];
            }
        }
        $stack .= "]";
        self::$instance->write(8, $stack . $msg);
    }

    public static function INFO($msg)
    {
        self::$instance->write(2, $msg);
    }

    private function getLevelStr($level)
    {
        switch ($level)
        {
        case 1:
            return 'debug';
        break;
        case 2:
            return 'info';  
        break;
        case 4:
            return 'warn';
        break;
        case 8:
            return 'error';
        break;
        default:

        }
    }

    protected function write($level,$msg)
    {
        if(($level & $this->level) == $level )
        {
            $msg = '['.date('Y-m-d H:i:s').']['.$this->getLevelStr($level).'] '.$msg."\n";
            $this->handler->write($msg);
        }
    }
}