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PHP的Try, throw 和 catch简单用法
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PHP的Try, throw 和 catch简单用法

Jun 13, 2016 am 09:06 AM
catch php try

PHP的Try, throw 和 catch简单用法

本文简单记录一下关于php中的 Try, throw 和 catch 的用法,后面有时间再做一个详细的解析。

Try - 使用异常的函数应该位于 "try" 代码块内。如果没有触发异常,则代码将照常继续执行。但是如果异常被触发,会抛出一个

异常。

Throw - 这里规定如何触发异常。每一个 "throw" 必须对应至少一个 "catch"

Catch - "catch" 代码块会捕获异常,并创建一个包含异常信息的对象

让我们触发一个异常:

<?php 
//创建可抛出一个异常的函数 
function checkNum($number){
	if($number>1){
		throw new Exception("Value must be 1 or below");
	}
	return true;
}
//在 "try" 代码块中触发异常 
try{
	checkNum(2);
//捕获异常
}catch(Exception $e){
	echo 'Message: ' .$e->getMessage();
}
Copy after login

上面代码将获得类似这样一个错误:

Message: Value must be 1 or below

例子解释:

上面的代码抛出了一个异常,并捕获了它:

创建 checkNum() 函数。它检测数字是否大于 1。如果是,则抛出一个异常。

在 "try" 代码块中调用 checkNum() 函数。

checkNum() 函数中的异常被抛出

"catch" 代码块接收到该异常,并创建一个包含异常信息的对象 ($e)。

通过从这个 exception 对象调用 $e->getMessage(),输出来自该异常的错误消息,不过,为了遵循“每个 throw 必须对应一个

catch 的原则,可以设置一个顶层的异常处理器来处理漏掉的错误。

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