157 lines
2.9 KiB
Markdown
157 lines
2.9 KiB
Markdown
---
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title: 🎉PHP 8.3发布与新特性
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date: 2023-11-23
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tags: PHP
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---
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PHP 8.3已经如期发不了，看一下新版特带来哪些特性！
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## 常量类型化(Typed class constants)
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定义常量目前可以标识类型了！
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8.3 之前
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```php
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interface I {
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// 过往历史长河中总是认为PHP常量总是一个字符串
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const PHP = 'PHP 8.2';
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}
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class Foo implements I {
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// 但是实现类可能会将其定义为数组。
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const PHP = [];
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}
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```
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8.3 之后
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```php
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interface I {
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const string PHP = 'PHP 8.3';
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}
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class Foo implements I {
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const string PHP = [];
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}
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//代码会发生致命错误：无法将数组用作类常量的值
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```
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<!--more-->
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## 动态类常量获取(Dynamic class constant fetch)
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8.3 之前
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```php
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class Foo {
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const PHP = 'PHP 8.2';
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}
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$searchableConstant = 'PHP';
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var_dump(constant(Foo::class . "::{$searchableConstant}"));
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```
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8.3 之后
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```php
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class Foo {
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const PHP = 'PHP 8.3';
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}
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$searchableConstant = 'PHP';
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var_dump(Foo::{$searchableConstant});
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```
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## #[\Override] 新注解
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通过将#[\Override]属性添加到方法中，PHP将确保在父类或实现的接口中存在具有相同名称的方法。如下面`MyTest`的父类`TestCase`中没有`taerDown`方法将抛出异常
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```php
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use PHPUnit\Framework\TestCase;
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final class MyTest extends TestCase {
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protected $logFile;
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protected function setUp(): void {
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$this->logFile = fopen('/tmp/logfile', 'w');
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}
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#[\Override]
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protected function taerDown(): void {
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fclose($this->logFile);
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unlink('/tmp/logfile');
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}
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}
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// Fatal error: MyTest::taerDown() has #[\Override] attribute,
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// but no matching parent method exists
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```
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## 深度克隆只读属性(Deep-cloning of readonly properties)
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只读属性现在可以在__clone方法中修改一次，以启用只读属性的深度克隆。
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8.3 之前
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```php
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class PHP {
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public string $version = '8.2';
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}
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readonly class Foo {
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public function __construct(
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public PHP $php
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) {}
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public function __clone(): void {
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$this->php = clone $this->php;
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}
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}
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$instance = new Foo(new PHP());
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$cloned = clone $instance;
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// Fatal error: Cannot modify readonly property Foo::$php
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```
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8.3 之后
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```php
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class PHP {
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public string $version = '8.2';
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}
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readonly class Foo {
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public function __construct(
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public PHP $php
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) {}
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public function __clone(): void {
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$this->php = clone $this->php;
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}
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}
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$instance = new Foo(new PHP());
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$cloned = clone $instance;
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$cloned->php->version = '8.3';
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```
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## json_validate 函数
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8.3 之前验证json 需要json_decode之后根据json_last_error()错误去判断，如今8.3新增json_validate函数支持
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## Randomizer 新特性
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1. getBytesFromString()
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2. getFloat()
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3. nextFloat()
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## 其他
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其余bug和特性请移步到，[php官方8.3发布页面介绍](https://www.php.net/releases/8.3/en.php)。
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