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Exception handling
PHP 5
Throw (throw) exception (exception) in the try code block and catch the exception in the catch code block
Each try must have at least one corresponding catch or finally block.
The object thrown must be an instance of the Exception class or a subclass of Exception, otherwise it will cause a PHP fatal error.
try { throw new Exception('异常提示语'); //throw 123; //Fatal error: Uncaught Error: Can only throw objects //throw new stdClass(); //Fatal error: Uncaught Error: Cannot throw objects that do not implement Throwable } catch (Exception $e) { echo $e->getMessage(); }
catch
You can use multiple catch blocks to catch different categories of exceptions.
Normal execution (when no exception is thrown within the try block) will continue after the last catch block defined in sequence.
Exceptions can be thrown (or re-thrown) in catch blocks.
When an exception is thrown, the code following the statement will not be executed and PHP will try to find the first matching catch block.
If the exception is not caught, a PHP fatal error will be issued with the message "Uncaught Exception..." unless a handler is defined using set_exception_handler().
finally
In PHP 5.5 and higher, the finally block can also be specified after the catch block or instead of the catch block.
Regardless of whether an exception is thrown, the code in the finally block will always be executed after the try and catch blocks before normal execution resumes.
Example #4 Exception handling with a finally block(用finally块处理异常)<?phpfunction inverse($x) { if (!$x) { throw new Exception('pision by zero.'); } return 1/$x; }try { echo inverse(5) . "\n"; } catch (Exception $e) { echo 'Caught exception: ', $e->getMessage(), "\n"; } finally { echo "First finally.\n"; }try { echo inverse(0) . "\n"; } catch (Exception $e) { echo 'Caught exception: ', $e->getMessage(), "\n"; } finally { echo "Second finally.\n"; }// Continue executionecho "Hello World\n";?>
Example #5 Nested Exception (嵌套异常)<?phpclass MyException extends Exception { }class Test { public function testing() { try { try { throw new MyException('foo!'); } catch (MyException $e) { // rethrow it throw $e; } } catch (Exception $e) { var_dump($e->getMessage()); } } }$foo = new Test;$foo->testing();?>
Note set_exception_handler()设置用户自定义的异常处理函数 Exception::getMessage 获取异常消息内容
Related recommendations:
[php classes and objects]Object serialization
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php除以100保留两位小数的方法:1、利用“/”运算符进行除法运算,语法“数值 / 100”;2、使用“number_format(除法结果, 2)”或“sprintf("%.2f",除法结果)”语句进行四舍五入的处理值,并保留两位小数。

判断方法:1、使用“strtotime("年-月-日")”语句将给定的年月日转换为时间戳格式;2、用“date("z",时间戳)+1”语句计算指定时间戳是一年的第几天。date()返回的天数是从0开始计算的,因此真实天数需要在此基础上加1。

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php判断有没有小数点的方法:1、使用“strpos(数字字符串,'.')”语法,如果返回小数点在字符串中第一次出现的位置,则有小数点;2、使用“strrpos(数字字符串,'.')”语句,如果返回小数点在字符串中最后一次出现的位置,则有。

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