php5.5新增 Finally模块try { //好好干，出了问题不要怕，外面有人接应} catch (HttpException $e) { //时刻准备着，处理上面抛出的HTTP问题} catch (Exception $e) { //时刻准备着，处理他们都处理不了的问题} finally { //打扫战场，都收拾好了再走人}try 中 return 后 finally 会继续执行，如果 finally 中也有return，则最终返回值为 finally 中 return 的值。try 中 die 或 exit 后 finally 不会执行。example01:

<?php/**finally块是个很好的设计，其中的return语句能覆盖其他块中的return语句，并处理try catch抛出的异常无需try-catch嵌套来处理子try-catch抛出的异常这个跟java的一样，c#是在finally块中存在return语句会抛出compile time error（编译时错误）*/function asdf(){    try {        throw new Exception('error');    }    catch(Exception $e) {        echo "An error occurred";        throw $e;    }    finally {                //This overrides the exception as if it were never thrown        return "\nException erased";    }}try {    echo asdf();}catch(Exception $e) {    echo "\nResult: " . $e->getMessage();}/* The output from above will look like this:     An error occurred     Exception erased Without the return statement in the finally block it would look like this:     An error occurred     Result: error*/

example02:

<?php/**有个相悖的行为在PHP 5.5.3's finally 和 return statements：在一个方法中，try块单返回一个变量，finally块修改这个变量，返回的是finally修改过的，但当try块返回的变量参与运算（evaluated in-line），会忽略finally块对这个变量的修改（不知道原因...）*/function returnVariable(){ $foo = 1; try{ return $foo; } finally { $foo++; } } function returnVariablePlusZero(){ $foo = 1; try{ return $foo+0; } finally { $foo++; } } $test1 = returnVariable(); // returns 2, not the correct value of 1. $test2 = returnVariablePlusZero(); // returns correct value of 1, but inconsistent with $test1.

example03:

<?php/**小例子 验证变量check if the name contains only letters, and does not contain the Word name*/$name = "Name";try{        try        {                //PReg_match() 返回 pattern  的匹配次数。 它的值将是0次（不匹配）或1次，因为 preg_match() 在第一次匹配后 将会停止搜索。 preg_match_all() 不同于此，它会一直搜索 subject  直到到达结尾。 如果发生错误 preg_match() 返回 FALSE 。                if(preg_match('/[^a-z]/i', $name))                {                        throw new Exception("$name contains character other than a-z A-Z");                }                if(strpos(strtolower($name), 'name') !== false)                {                        throw new Exception("$name contains the word name");                }                echo "The Name is valid";        }        catch (exception $e)        {                throw new Exception("insert name again", 0, $e);        }}catch (exception $e){        if($e->getPrevious())        {                echo "The Previous Exception is: " . $e->getPrevious()->getMessage() . "<br/>";        }        echo "The Exception is: " . $e->getMessage() . "<br/>";}

example04

<?php/*When catching an exception inside a namespace it is important that you escape to the global space:如何逃离出命名空间*/ namespace SomeNamespace; class SomeClass {  function SomeFunction() {   try {    throw new Exception('Some Error Message');   } catch (\Exception $e) {    var_dump($e->getMessage());   }  } }//报错：//Fatal error: Class 'SomeNamespace\Exception' not found in C:\xampp\htdocs\tonglei\index.php on line 8

example05

<?php//下面的写法会报T_THROW Syntax Error.someFunction() OR throw new Exception();//这种写法可以用下面这个正确的形式function throwException($message = null,$code = null) {    throw new Exception($message,$code);}someFunction() OR throwException();