Using examples to understand PHP5 exception handling _php Tutorial

The writing of a program inevitably presents a variety of errors, so how can I handle these errors, or display errors so that we can find the changes? This uses the exception handling. Here we will introduce the concepts related to 5 exception handling.

PHP5 Exception Handling

PHP 5 adds exception handling modules similar to those in other languages. Exceptions generated in PHP code can be thrown by a throw statement and captured by a catch statement. The code that requires exception handling must be placed inside a try code block to catch possible exceptions.

Each try must have at least one catch corresponding to it. You can use multiple catches to catch exceptions that are generated by different classes. When the try code block no longer throws an exception or cannot find a catch that matches the thrown exception, the PHP code resumes execution after jumping to the last catch.

Of course, PHP5 exception handling allows you to throw (throw) exceptions again within a catch code block. When an exception is thrown, the code behind it (the code block where the exception was thrown) will not continue, and PHP will attempt to find the first catch to match it.

If an exception is not captured and does not use Set_exception_handler () for the appropriate processing, then PHP will produce a serious error and output uncaught exception ... (The exception is not caught) prompt information.

The properties and methods of exception class for PHP5 exception handling

The following code is only a description of the structure of the built-in exception-handling class, and it is not a meaningful piece of code available.

 
 

  
  

  
 
  
  

  
Class exception{
  
  

  
protected $ message  =  ' Unknown
Exception '; 
  
  

  
Exception information
  
  

  
protected $ Code  =  0 ; 
  
  

  
User-defined exception codes
  
  

  
protected $file;
  
  

  
The file name of the exception that occurred
  
  

  
protected $line;
  
  

  
The line number of the code where the exception occurred
  
  

  
function __construct ($message  =
NULL , $ Code  =  0 ); 
  
  

  
Final function getMessage ();
  
  

  
Return exception information
  
  

  
Final function GetCode ();
  
  

  
Return exception code (codename)
  
  

  
Final function getFile ();
  
  

  
Returns the file name of the exception that occurred
  
  

  
Final function getLine ();
  
  

  
Returns the line number of the code where the exception occurred
  
  

  
Final function gettrace ();
  
  

  
BackTrace () array
  
  

  
Final function gettraceasstring ();
  
  

  
Gettrace () information that has been rasterized into a string
  
  

  
Methods that can be overloaded
  
  

  
function __tostring ();
  
  

  
A string that can be output
  
  

  
}
  
  

  
? >
  
  

  

 
 

The above is the analysis of PHP5 exception handling, I hope that the need for a friend to help.

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