PHP异常处理浅析

Exception {
??? /* 属性 */
??? protected string $message ; //异常消息内容
??? protected int $code ; //异常代码号
??? protected string $file ; //抛出异常的文件名
??? protected int $line ; //抛出异常在该文件中的行号
??? /* 办法 */
??? public __construct ([ string $message = "" [,int $code = 0 [,Exception $previous = null]]] )
??? final public string getMessage ( void ) //异常抛出的信息
??? final public Exception getPrevious ( void ) //前一异常
??? final public int getCode ( void ) //异常代码,这是用户自定义的
??? final public string getFile ( void ) //发生异常的文件路劲
??? final public int getLine ( void ) //发生异常的行
??? final public array getTrace ( void ) //异常追踪信息(array)
??? final public string getTraceAsString ( void ) //异常追踪信息(string)
??? public string __toString ( void ) //试图直接 将异常对象当作字符串使用时调用子函数的返回值
??? final private void __clone ( void ) //克隆异常对象时调用
}

ErrorException? extends Exception? {
?
??? /* 属性 */
??? protected int $severity?? ;
??? /* 办法 */
???
??? public __construct? ([ string $message? = ""? [,int $code? = 0? [,int $severity? = 1? [,string $filename? = __FILE__? [,int $lineno? = __LINE__? [,Exception? $previous? = NULL??? ]]]]]] )
??? final public int getSeverity? ( void )
??? /* 继承的办法 */
??? final public string Exception::getMessage? ( void )
??? final public Exception Exception::getPrevious? ( void )
??? final public int Exception::getCode? ( void )
??? final public string Exception::getFile? ( void )
??? final public int Exception::getLine? ( void )
??? final public array Exception::getTrace? ( void )
??? final public string Exception::getTraceAsString? ( void )
??? public string Exception::__toString? ( void )
??? final private void Exception::__clone? ( void )
}

try {
??? throw new Exception('exception test 1',1001);
} catch(Exception $e) {
??? echo $e->getMessage().'-'.$e->getCode();
}

function? exception_handler ( $e ) {
??? echo? "Uncaught exception: "?,? $e -> getMessage (),? "n" ;
}
?
set_exception_handler ( 'exception_handler' );
?
throw new? Exception ( 'Uncaught Exception' );
?
echo "这行不会执行了";

//请根据实际扩展非常类
class MyException extends Exception {
??? public function __construct($message = '',$code = 0) {
?
??? }
?
??? public function myFunction() {
??????? echo 'just for test';
??? }
}
?
try {
??? throw new MyException('an error');
} catch (MyException $e) {
??? echo $e->myFunction();
} catch (Exception $e) {
??? echo $e->getMessage();
}

function doSomething() {
??? $resource = createResource();
??? try {
??????? $result = useResource($resource);
??? } catch (Exception $e) {
??????? releaseResource($resource);
??????? log($e->getMessage());
??????? exit();
??? }
??? releaseResource($resource);
??? return $result;
}
?
//使用finally后
function doSomething2() {
??? $resource = createResource();
??? try {
??????? $result = useResource($resource);
??????? return $result;
??? } catch (Exception $e) {
??????? log($e->getMessage());
??????? exit();
??? } finally {
??????? releaseResource($resource);
??? }
}