(4) PHP object-oriented Theory 4 --- exception and error handling

: This article mainly introduces (4) PHP object-oriented Theory 4-exception and error handling. if you are interested in PHP tutorials, refer to it. I. exception handling:
1. PHP exception example:

 GetMessage (); $ a =-1;} echo $;

2. detailed exception example:

 Exception ($ this-> getCode (): {$ this-> getMessage ()} in File :( $ this-> getFile () on Line: {$ this-> getLine ()}
";}} Function reg ($ reginfo = null) {if (empty ($ reginfo) | isset ($ reginfo) {throw new Exception (" Invalid parameter ");} if (empty ($ reginfo ['email ']) {throw new emailException ("the email is blank");} if ($ reginfo ['pwd']! = $ Reginfo ['repwd']) {throw new pwdException ("two passwords inconsistent");} echo "registered successfully" ;}/ ** this code cannot be executed, find out the reason */try {reg (array ('email '=> 'waitfox @ qq.com', 'pwd' => 123456, 'repwd' => 12345678 ));} catch (emailException $ ee) {echo $ ee-> getMessage ();} catch (pwdException $ ep) {echo $ ep; echo PHP_EOL, "special processing ";} catch (Exception $ e) {echo $ e-> getTraceAsString (); echo PHP_EOL, "Unified processing in other cases ";}

3. exception handling scenarios:
A. pessimistic prediction of the program
B. program needs and business concerns
C. language-level Robustness Requirements: capture exceptions and remedy them accordingly
3. exception handling: The exception must be handled in a reasonable scenario.
II. PHP error levels:
1. PHP error level:
A. deprecated: minimum level. 'Not recommended, not recommend'
B. notice: incorrect syntax. For example, variables are used but not defined.
C. warning: function parameters do not match
D. fetal error: The PHP process is terminated, and subsequent code is not executed.
E. prase error: This error will be reported during the syntax check phase. The PHP Manual defines 16 levels of errors.
2. example:

 5) {echo "$ I not initialized", PHP_EOL;} $ a = array ('O' => 2, 4, 6, 8); echo $ a [o]; $ result = array_sum ($ a, 3); echo fun (); echo "error ...... Can I continue? ";

4. PHP error handling mechanism:

 Error code:[$ {Errno}], file {$ errstr} \ r \ n "; echo" error code line: {$ errline} File {$ errfile} \ r \ n "; echo" PHP version ", PHP_VERSION," (", PHP_ OS,") \ r \ n ";} set_error_handler ("customeError", E_ALL | E_STRICT); $ a = array ('O' => 2, 4, 6, 8); echo $ a ['O']; // no answer to this question. No error reported

III. PHP object-oriented summary:
PHP object-oriented knowledge points: Magic methods, interfaces, polymorphism, class multiplexing, reflection, and exception mechanisms.
PHP also introduces some functional programming concepts.

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