预定义异常

Exception是所有异常的基类，类摘要如下：

<?php class Exception {	protected string $message;  // 异常消息内容	protected int $code;  // 异常代码	protected string $file;  // 抛出异常的文件名	protected int $line;  // 抛出异常在该文件的行号	public __construct([string $message = "" [, int $code = 0 [, Exception $previous = NULL]]])	final public string getMessage(void)	final public Exception getPrevious(void)	final public int getCode(void)	final public string getFile(void)	final public int getLine(void)	final public array getTrace(void)	final public string getTraceAsString(void)	public string __toString(void)	final private void __clone(void)}

ErrorException是错误异常，类摘要如下：

<?php class ErrorException extends Exception {	protected int $severity;  // 异常级别	public __construct([string $message = "" [, int $code = 0 [, int $severity = 1 [, string $filename = __FILE__ [, int $lineno = __LINE__ [, Exception $previous = NULL]]]]]])	final public int getSeverity(void)}

（全文完）