PHP automatically loads objects (take the MVC framework as an example)

PHP automatically loads objects (using the MVC framework as an example) & lt ;? Phpclassautoloader {publicstatic $ loader; publicstaticfunctioninit () {if (self ::$ loaderNULL) self ::$ loadernewself (); PHP automatically loads objects (take the MVC framework as an example)

1. when the program uses an undeclared class, the _ autolaod () function is automatically called for loading;

2. spl_autoload_register () is used to register an automatically called function. you can register multiple functions!

3. $ iniPath = ini_get ('include _ path'); ini_set ('include _ path', $ iniPath .. $ cPath); set environment variables to achieve autoload. set the include path. you can directly include the files in these directories without writing detailed paths. Method 3: use php. MVC.

 Setup the application class paths (PHP 'include_path') for the included* class files, for the duration of the main script
**
Returns the class path string for testing purposes** @depreciated* @param stringThe appServerRootDir. eg: 'C:/Www/phpmvc'* @param arrayAn array of sub-application paths,
*  eg: $subAppPaths[] = 'WEB-INF/classes/example';, ...* @param stringThe OS [Optional] [UNIX|WINDOWS|MAC|...] if we have*  trouble detecting the server OS type. Eg: path errors.* @public* @returns string*/function setClassPath($appServerRootDir='', $subAppPaths='', $osType='') {// Set AppServer root manually for nowif($appServerRootDir == '') {echo 'Error: ClassPath :- No php.MVC application root directory specified';exit;}#$_ENV;// PHP Superglobals !!// Setup the main phpmvc application include() directories here// Note: could be placed in a n xml config file later !!$appDirs = array();$appDirs[] = ''; // application root directory$appDirs[] = 'lib';// Add the sub-application paths, if anyif(is_array($subAppPaths)) {$appDirs = array_merge($appDirs, $subAppPaths);}// Setup the platform specific path delimiter character$delim = NULL;// path delimiter character. (Windows, Unix, Mac!!)$winDir = NULL;if( (int)phpversion() > 4 ) {// PHP 5$winDir = $_ENV["windir"];// See: PHP v.4.1.0 Superglobals } else {// PHP 4global $HTTP_ENV_VARS;// depreciated- if( array_key_exists("windir", $HTTP_ENV_VARS) ) {$winDir = $HTTP_ENV_VARS["windir"];// will be replaced with $_ENV}}if($osType != '') {if( eregi("WINDOWS", $osType) ) {$delim = ';';// Windows} elseif( eregi("UNIX", $osType) ) {$delim = ':';// Unix} elseif( eregi("MAC", $osType) ) {$delim = ':';// Mac !!!!!}}if($delim == NULL) {if( eregi("WIN", $winDir) ) { // _ENV["C:\\Win2K"]    $delim = ';';// Windows} else {$delim = ':';// Unix, Mac !!}}// Get the current working directory$path = $appServerRootDir;// Strip path directories below 'WEB-INF'$pathToWebInf = ereg_replace("WEB-INF.*$", '', $path);// Replace path backslashes with forward slashes// Note: PHP Regular Expressions do not work with backslashes$pathToWebInf = str_replace("\\", "/", $pathToWebInf);// Drop the trailing slash, if one is present$pathToWebInf = ereg_replace("/$", '', $pathToWebInf);// Setup the environment path string$classPath = NULL;foreach($appDirs as $appDir) {$classPath .= $pathToWebInf.'/'.$appDir.$delim;}// Remove trailing delimiter character$classPath = substr($classPath, 0, -1);// Setup the include_path for the duration of the main php.MVC scriptini_set('include_path', $classPath);return $classPath;// for testing}// ----- Public Methods ------------------------------------------------- //function getClassPath($appServerRootDir='', $appDirs, $osType='') {// Set AppServer root manually for nowif($appServerRootDir == '') {echo 'Error: ClassPath :- No php.MVC application root directory specified';exit;}#$_ENV;// PHP Superglobals !!// Setup the platform specific path delimiter character$delim = NULL;// path delimiter character. (Windows, Unix, Mac!!)if($osType == '') {// PHP's build in constant "PATH_SEPARATOR" [unix (:) / win (;)]$delim = PATH_SEPARATOR;} else {// It is handy to be able to specift the OS type for testing$delim = ClassPath::getPathDelimiter($osType);}// Get the current working directory$path = $appServerRootDir;// Strip path directories below 'WEB-INF'$pathToWebInf = ereg_replace("WEB-INF.*$", '', $path);// Replace path backslashes with forward slashes// Note: PHP Regular Expressions do not work with backslashes$pathToWebInf = str_replace("\\", "/", $pathToWebInf);// Drop the trailing slash, if one is present$pathToWebInf = ereg_replace("/$", '', $pathToWebInf);// Setup the environment path string$classPath= NULL;$AbsolutePath= False;// Say: "/Some/Unix/Path/" or "D:\Some\Win\Path"foreach($appDirs as $appDir) {// Check if the specified system path is an absolute path. Absolute system// paths start with a "/" on Unix, and "Ch\:" or "Ch/:" on Win 32.// Eg: "/Some/Unix/Path/" or "D:\Some\Win\Path" or "D:/Some/Win/Path".$AbsolutePath = ClassPath::absolutePath($appDir);if($AbsolutePath == True) {$classPath .= $appDir.$delim;} else {$classPath .= $pathToWebInf.'/'.$appDir.$delim;}}// Remove trailing delimiter character$classPath = substr($classPath, 0, -1);return $classPath;// for testing}/*** Concatenate environment path strings* 
* Returns the two path strings joined with the correct environment* string delimiter for the host operating system.* * @paramstringThe path string* @paramstringThe path string* @paramstringThe operating type [optional]* @public* @returnsstring*/function concatPaths($path1, $path2, $osType='') {// Setup the platform specific path delimiter character$delim = NULL;// path delimiter character. (Windows, Unix, Mac!!)$delim = ClassPath::getPathDelimiter($osType);$path = $path1 . $delim . $path2;return $path;}// ----- Protected Methods ---------------------------------------------- ///*** Get environment path delimiter.* 
* Returns the environment string delimiter for the host operating system.** @paramstringThe operating type [optional]* @protected* @returnsstring*/function getPathDelimiter($osType='') {// Setup the platform specific path delimiter character$delim = NULL;// path delimiter character. (Windows, Unix, Mac!!)$winDir = NULL;if( (int)phpversion() > 4 ) {// PHP 5$winDir = $_ENV["windir"];// See: PHP v.4.1.0 Superglobals } else {// PHP 4global $HTTP_ENV_VARS;// depreciated- if( array_key_exists("windir", $HTTP_ENV_VARS) ) {$winDir = $HTTP_ENV_VARS["windir"];// will be replaced with $_ENV}}if($osType != '') {if( eregi("WINDOWS", $osType) ) {$delim = ';';// Windows} elseif( eregi("UNIX", $osType) ) {$delim = ':';// Unix} elseif( eregi("MAC", $osType) ) {$delim = ':';// Mac !!!!!}}if($delim == NULL) {if( eregi("WIN", $winDir) ) { // _ENV["C:\\Win2K"]    $delim = ';';// Windows} else {$delim = ':';// Unix, Mac !!}}return $delim;}/** * Check if the specified system path is an absolute path. Absolute system* paths start with a "/" on Unix, and "Ch\:" or "Ch/:" on Win 32.* Eg: "/Some/Unix/Path/" or "D:\Some\Win\Path" or "D:/Some/Win/Path".** Returns True if the suppplied path absolute, otherwise returns False** @param stringThe path to check, like: "/Some/Unix/Path/" or*"D:\Some\Win\Path".* @public* @returns boolean*/function absolutePath($systemPath) {// Say: "/Some/Unix/Path/" or "D:\Some\Win\Path" or "D:/Some/Win/Path"$fAbsolutePath= False;// Boolean flag value//"[/]Some/Unix/Path/"if (preg_match("/^\//", $systemPath)) {$fAbsolutePath = True;//"[D:\]Some\Win\Path"// "i" says "ignore case"// Note the extra escape "\" reqd for this to work with  PHP !!!} elseif(preg_match("/^[a-z]:\\\/i", $systemPath)) {$fAbsolutePath = True;//"[D:/]Some/Win/Path"} elseif(preg_match("/^[a-z]:\//i", $systemPath)) {$fAbsolutePath = True;}return $fAbsolutePath;}}?>

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? Call method autoloader. php