PHP 8.1十大新功能：新的函数新的类

1.枚举2.Fiber（纤维）3.never返回类型4.readonly属性5.final类常量6.新的array_is_list()函数7.新的fsync()和fdatasync()函数8.对字符串键数组解包的支持9.$_FILES新的用于目录上传的full_path键10.新的IntlDatePatternGenerator类

/** * Declare an enumeration. * It can also contain an optional 'string' or 'int' value. This is called backed Enum. * Backed enums (if used) should match the following criteria: * - Declare the scalar type, whether string or int, in the Enum declaration. * - All cases have values. * - All cases contain the same scalar type, whether string or int. * - Each case has a unique value. */enum UserRole: string {    case ADMIN    = '1';    case GUEST    = '2';    case WRITER   = '3';    case EDITOR   = '4';}
/** * You can access a case by using * the '::' scope resolution operator. * And, to get the name of the enum case, you * can use the '->' followed by the attribute 'name'. */echo UserRole::WRITER->name;
/** * To get the value of the enum case, you can * use the '->' followed by the attribute 'value'. */echo UserRole::WRITER->value;
?>

/** * Initialize the Fiber. */$fiber = new Fiber(function(): void {    /**     * Print some message from inside the Fiber.     * Before the Fiber gets suspended.     */    echo "Welcome to Fiber!\n";    /**     * Suspend the Fiber.     */    Fiber::suspend();    /**     * Print some message from inside the Fiber.     * After the Fiber gets resumed.     */    echo "Welcome back to Fiber!\n";});
/** * Print a message before starting a Fiber. */echo "Starting a Fiber\n";/** * Start the Fiber. */$fiber->start();/** * Fiber has been suspened from the inside. * Print some message, and then resume the Fiber. */echo "Fiber has been suspended\n";echo "Resuming the Fiber\n";/** * Resume the Fiber. */$fiber->resume();/** * End of the example. */echo "Fiber completed execution\n";
?>

/** * Route Class */class Route {
    /**     * Constructor of the class     * @return void     */    public function __construct() {
    }
    /**     * Redirect To a Page     * This function redirects to an URL specified by the user.     * @method redirect()     * @param string $url     * @param integer $httpCode     * @author Tara Prasad Routray <someemailaddress@example</someemailaddress.com>     * @access public     * @return never     */    public static function redirect($url, $httpCode = 301): never {        /**         * Redirect to the URL specified.         */        header("Location: {$url}", true, $httpCode);        die;    }}
Route::redirect('https://www.google.com');
?>

/** * User Class */class User {    /**     * Declare a variable with readonly property.     * @var $authUserID     * @access public     */    public readonly int $authUserID;    /**     * Constructor of the class.     * @param integer $userID     * @return void     */    public function __construct($userID) {        /**         * Change the value of the property as specified.         * Updating the value of readonly properties are         * allowed only through the constructor.         */        $this->authUserID = $userID;    }    /**     * Update Auth User ID     * This function tries to update the readonly property (which is not allowed).     * @method updateAuthUserID()     * @param integer $userID     * @author Tara Prasad Routray <someemailaddress@example</someemailaddress.com>     * @access public     * @return void     */    public function updateAuthUserID($userID) {        /**         * Change the value of the property as specified.         * Executing this function will throw the following error;         * PHP Fatal error:  Uncaught Error: Cannot modify readonly property User::$authUserID         */        $this->authUserID = $userID;    }}/** * Initialize the class and update the value of the readonly property. */$user = new User(30);/** * Print the readonly property value. * This will print 30. */echo $user->authUserID;/** * Call another function inside the class and try to update the class property. */$user->updateAuthUserID(50);/** * Print the readonly property value. */echo $user->authUserID;
?>

/** * UserRole Class */class UserRole {    /**     * Declare a final class constant with a value.     */    final public const ADMIN = '1';}
/** * User Class extending the UserRole Class */class User extends UserRole {    /**     * Declare another constant with the same name     * as of the parent class to override the value.     *      * Note: Overriding the value will throw the following error:     * PHP Fatal error:  User::ADMIN cannot override final constant UserRole::ADMIN     */    public const ADMIN = '2';}
?>

/** * Returns true for empty array. */array_is_list([]);/** * Returns true for sequential set of keys. */array_is_list([1, 2, 3]);/** * Returns true as the first key is zero, and keys are in sequential order. * It is same as [0 => 'apple', 1 => 2, 2 => 3] */array_is_list(['apple', 2, 3]);/** * Returns true as the first key is zero, and keys are in sequential order. * It is same as [0 => 'apple', 1 => 'scissor'] */array_is_list(['apple', 'orange']);/** * Returns true as the first key is zero, and keys are in sequential order. * It is same as [0 => 'apple', 1 => 'scissor'] */array_is_list([0 => 'apple', 'orange']);/** * Returns true as the first key is zero, and keys are in sequential order. */array_is_list([0 => 'rock', 1 => 'scissor']);
?>

/** * Returns false as the first key does not start from zero. */array_is_list([1 => 'apple', 'orange']);/** * Returns false as the first key does not start from zero. */array_is_list([1 => 'apple', 0 => 'orange']);/** * Returns false as all keys are not integer. */array_is_list([0 => 'apple', 'fruit' => 'orange']);/** * Returns false as the keys are not in sequential order. */array_is_list([0 => 'apple', 2 => 'orange']); 
?>

/** * Declare a variable and assign a filename. */$fileName = 'notes.txt';/** * Create the file with read and write permission. */$file = fopen($fileName, 'w+');/** * Add some text into the file. */fwrite($file, 'Paragraph 1');/** * Add a line break into the file. */fwrite($file, "\r\n");/** * Add some more text into the file. */fwrite($file, 'Paragraph 2');/** * You can use both the fsync() or fdatasync() functions  * to commit changs to disk. */fsync($file); // or fdatasync($file)./** * Close the open file pointer. */fclose($file);
?>

/** * Declare an array */$fruits1 = ['Jonathan Apples', 'Sapote'];/** * Declare another array */$fruits2 = ['Pomelo', 'Jackfruit'];/** * Merge above two arrays using array unpacking. */$unpackedFruits = [...$fruits1, ...$fruits2, ...['Red Delicious']];/** * Print the above unpacked array. * This will print: * array(5) { * [0]=> * string(15) "Jonathan Apples" * [1]=> * string(6) "Sapote" * [2]=> * string(6) "Pomelo" * [3]=> * string(9) "Jackfruit" * [4]=> * string(13) "Red Delicious" * } */var_dump($unpackedFruits);
?>

/** * Check if the user has submitted the form. */if ($_SERVER['REQUEST_METHOD'] === 'POST') {    /**     * Print the $_FILES global variable. This will display the following:     * array(1) {     *   ["myfiles"]=> array(6) {     *     ["name"]=> array(2) {     *       [0]=> string(9) "image.png"     *       [1]=> string(9) "image.png"     *     }     *     ["full_path"]=> array(2) {     *       [0]=> string(25) "folder1/folder2/image.png"     *       [1]=> string(25) "folder3/folder4/image.png"     *     }     *     ["tmp_name"]=> array(2) {     *       [0]=> string(14) "/tmp/phpV1J3EM"     *       [1]=> string(14) "/tmp/phpzBmAkT"     *     }     *     // ... + error, type, size     *   }     * }     */    var_dump($_FILES);}
?>

/** * Define a default date format. */$skeleton = "YYYY-MM-dd";/** * Parse a time string (for today) according to a specified format. */$today = \DateTimeImmutable::createFromFormat('Y-m-d', date('Y-m-d'));/** * =========================== * PRINTING DATE IN USA FORMAT * =========================== * Initiate an instance for the IntlDatePatternGenerator class * and provide the locale information. * In the below example, I've used locale: en_US. */ $intlDatePatternGenerator = new \IntlDatePatternGenerator("en_US");/** * Get the correct date format for the locale: en_US. * Following function "getBestPattern" will return: * MM/dd/YYYY */$enUSDatePattern = $intlDatePatternGenerator->getBestPattern($skeleton);/** * Use the "formatObject" function of IntlDateFormatter to print as per specified pattern. * This will print the following: * Date in en-US: 12/03/2021 */echo "Date in en-US: ". \IntlDateFormatter::formatObject($today, $enUSDatePattern, "en_US"). "\n";
/** * ============================= * PRINTING DATE IN INDIA FORMAT * ============================= * Initiate an instance for the IntlDatePatternGenerator class * and provide the locale information. * In the below example, I've used locale: en_IN. */$intlDatePatternGenerator = new \IntlDatePatternGenerator("en_IN");/** * Get the correct date format for the locale: en_IN. * Following function "getBestPattern" will return: * dd/MM/YYYY */$enINDatePattern = $intlDatePatternGenerator->getBestPattern($skeleton);/** * Use the "formatObject" function of IntlDateFormatter to print as per specified pattern. * This will print the following: * Date in en-IN: 03/12/2021 */echo "Date in en-IN: ". \IntlDateFormatter::formatObject($today, $enINDatePattern, "en_IN"). "\n";
?>