php error and exception handling

Unlike java, in php, exceptions must be thrown manually.

throw and catch an exception, example:

<?php
try{
    throw new <strong>Exception</strong>("A terrible error has occurred",42);
}catch (<strong>Exception</strong> $e){
    echo "<strong>Exception</strong> ".$e->getCode().":".$e->getMessage()."<br/>"."in".$e->getFile()." on line".$e->getLine()."<br/>";
}

shows the result:

ExceptionBuilt-in methods of the class:

getCode() - Returns the code passed to the constructor;

getMessage() - Returns the pass Message to the paparazzi function;

getFile() - returns the full path of the code file that generated the exception;

getLine() - returns the code line number in the code file that generated the exception ;

getTrance - Returns an array containing the code rollback path that generated the exception;

getTranceAsString - Returns a message in the same direction as getTrance(), which will be formatted String;

__toString() - Allows to simply display an Exception object and give the information that all the above methods can provide.

User-defined exception example:

<?php
//自定义异常
class my<strong>Exception</strong> extends <strong>Exception</strong>{
    function __toString(){
        return "<strong>Exception</strong> ".$this->getCode().":".$this->getMessage()."<br/>"."in".$this->getFile()." on line".$this->getLine()."<br/>";
    }
}

try{
    throw new my<strong>Exception</strong>("A terrible error has occurred",42);
}catch (my<strong>Exception</strong> $m){
    echo $m;
}

An example of applying Exception handling: file I/O processing

First you need to create an exception class file: file_Exception.php

<?php

//自定义文件打开异常
class fileOpen<strong>Exception</strong> extends <strong>Exception</strong>{
    function __toString(){
        return "fileOpen<strong>Exception</strong> ".$this->getCode().":".$this->getMessage()."<br/>"."in".$this->getFile()." on line".$this->getLine()."<br/>";
    }
}

//自定义无法写入异常
class fileWrite<strong>Exception</strong> extends <strong>Exception</strong>{
    function __toString(){
        return "fileWrite<strong>Exception</strong> ".$this->getCode().":".$this->getMessage()."<br/>"."in".$this->getFile()." on line".$this->getLine()."<br/>";
    }
}
//自定义无法获得写锁异常
class fileLock<strong>Exception</strong> extends <strong>Exception</strong>{
    function __toString(){
        return "fileLock<strong>Exception</strong> ".$this->getCode().":".$this->getMessage()."<br/>"."in".$this->getFile()." on line".$this->getLine()."<br/>";
    }
}

and then introduce the file.Exception.php file into the main file processorder.php file

<strong>require</strong>_once ("file_<strong>Exception</strong>.php");

Exception handlingKey code:

 //设置文件输出内容和格式
    $out_put_string=$date."\t".$cloths."件男装\t".$shoes."双鞋子\t".$glasses."副眼镜\t\总价：￥".$total_amount." 收货地址：\t".$address."\n";

    //<strong>异常处理</strong>
    try{
        //打开文件,（追加模式+二进制模式）
        if(!($fp=@fopen("$DOCUMENT_ROOT/L02/files/orders.txt",'ab')))
            throw new fileOpen<strong>Exception</strong>();
        //写操作锁定
        if(!flock($fp,LOCK_EX))
            throw new fileLock<strong>Exception</strong>();
        //将数据写入到文件
        if(!fwrite($fp,$out_put_string,strlen($out_put_string)))
            throw new fileWrite<strong>Exception</strong>();
        //释放已有的锁定
        flock($fp,LOCK_UN);
        //关闭文件流
        fclose($fp);
        echo "<p>数据保存完成</p>";
    }catch (fileOpen<strong>Exception</strong> $foe){
        echo "<p><strong>文件打开失败，请查看服务器是否异常！</strong></p>";
        exit;
    }catch(<strong>Exception</strong> $e){
        echo "<p><strong>您的订单没有提交完成，请再试一次。</strong></p>";
        exit;
    }

The above introduces the error and exception handling of PHP, including the relevant content. I hope it will be helpful to friends who are interested in PHP tutorials.