PHP 链式操作 - 学习/实践

向右看齐 2023-07-17 06:58 3阅读 0赞

1.应用场景

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 <td>了解学习借鉴 php[框架中]实现链式操作实现原理</td> 
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2.学习/操作

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 <td> 测试环境: win10 64位 专业版 &nbsp; 2.1 //适用于php 自带的内置函数调用 比如: 
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 在php中有很多字符串函数，例如要先过滤字符串收尾的空格，再求出其长度，一般的写法是： strlen(trim($str)) 如果要实现类似js中的链式操作，比如像下面这样应该怎么写？ $str-&gt;trim()-&gt;strlen() 
 </blockquote> 1. 方式一&nbsp;使用魔法函数__call结合call_user_func来实现 
 <blockquote> 
 &lt;?php class StringHelper&nbsp; { &nbsp; private $value; &nbsp; &nbsp; &nbsp; public function __construct($value) &nbsp; { &nbsp; &nbsp; $this-&gt;value = $value; &nbsp; } &nbsp; &nbsp; public function __call($function, $args){ &nbsp; &nbsp;&nbsp; &nbsp;//var_export($function); // trim &nbsp; &nbsp;&nbsp; &nbsp;//var_export($args); // array ( 0 =&gt; '0', ) &nbsp; &nbsp;&nbsp; &nbsp;//exit; &nbsp; &nbsp; $this-&gt;value = call_user_func($function, $this-&gt;value, $args[0]);&nbsp;//这里参数是根据 要调用函数[闭包]的参数而定 trim('str', '0'); &nbsp; &nbsp; return $this; &nbsp; } &nbsp; &nbsp; function strlen() { &nbsp; &nbsp; return strlen($this-&gt;value); &nbsp; } } 
 $str = " sd f 0"; $str = new StringHelper($str); echo $str-&gt;trim('0')-&gt;strlen(); &nbsp;//处理字符串两遍0的字符 
 </blockquote> 输出: <img alt="" height="106" src="https://img-blog.csdnimg.cn/20200321215440352.png" width="372"> &nbsp; &nbsp; 
 <blockquote> 
 2. 方式二&nbsp;&nbsp;使用魔法函数__call结合call_user_func_array来实现 class StringHelper&nbsp; { &nbsp; private $value; &nbsp; &nbsp; &nbsp; public function __construct($value) &nbsp; { &nbsp; &nbsp; $this-&gt;value = $value; &nbsp; } &nbsp; &nbsp; public function __call($function, $args){ &nbsp; &nbsp; //&nbsp; var_export($args); // array ( 0 =&gt; '0', ) &nbsp; &nbsp; array_unshift($args, $this-&gt;value); &nbsp; &nbsp; // var_export($args); // array ( 0 =&gt; ' sd f 0', 1 =&gt; '0', ) &nbsp; &nbsp; // exit; &nbsp; &nbsp; $this-&gt;value = call_user_func_array($function, $args); //依然是按照回调函数的参数顺序而定的, 只不过第二个参数是数组形式 &nbsp; &nbsp; return $this; &nbsp; } &nbsp; &nbsp;public function strlen() { &nbsp; &nbsp; return strlen($this-&gt;value); &nbsp; } } &nbsp; $str = new StringHelper(" sd f 0"); echo $str-&gt;trim('0')-&gt;strlen(); 
 </blockquote> 输出: <img alt="" height="105" src="https://img-blog.csdnimg.cn/202003212212501.png" width="369"> &nbsp; 备注: array_unshift() 函数用于向数组插入新元素。新数组的值将被插入到数组的开头。 call_user_func()和call_user_func_array都是动态调用函数的方法，区别在于参数的传递方式不同。 &nbsp; 3.方式三&nbsp;&nbsp;不使用魔法函数__call来实现 &nbsp; 只需要修改_call()为trim()函数即可： &nbsp; 
 <blockquote> 
 class StringHelper&nbsp; { &nbsp;&nbsp; &nbsp;private $value; 
 &nbsp; &nbsp; public function __construct($value) &nbsp;&nbsp; &nbsp;{ &nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;$this-&gt;value = $value; &nbsp;&nbsp; &nbsp;} 
 &nbsp;&nbsp; &nbsp;public function trim($t) &nbsp;&nbsp; &nbsp;{ &nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;$this-&gt;value = trim($this-&gt;value, $t); &nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;return $this; &nbsp;&nbsp; &nbsp;} 
 &nbsp;&nbsp; &nbsp;public function strlen() { &nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;return strlen($this-&gt;value); &nbsp;&nbsp; &nbsp;} } 
 $str = " sd f 0"; $str = new StringHelper($str); echo $str-&gt;trim('0')-&gt;strlen(); 
 </blockquote> 输出: <img alt="" height="105" src="https://img-blog.csdnimg.cn/202003212212501.png" width="369"> &nbsp; 
 <blockquote> 
 扩展:&nbsp; [方式三 扩展为可以 不分顺序调用] class StringHelper&nbsp; { &nbsp;&nbsp; &nbsp;private $value; 
 &nbsp;&nbsp; &nbsp;public function __construct($value) &nbsp;&nbsp; &nbsp;{ &nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;$this-&gt;value = $value; &nbsp;&nbsp; &nbsp;} 
 &nbsp;&nbsp; &nbsp;public function __toString() { &nbsp; &nbsp; &nbsp; &nbsp; return (string)$this-&gt;value; //必须返回string类型 &nbsp; &nbsp; } 
 &nbsp;&nbsp; &nbsp;public function trim($t) &nbsp;&nbsp; &nbsp;{ &nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;$this-&gt;value = trim($this-&gt;value, $t); &nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;return $this; &nbsp;&nbsp; &nbsp;} 
 &nbsp;&nbsp; &nbsp;public function strlen() { &nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;$this-&gt;value = strlen($this-&gt;value); &nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;//echo $this-&gt;value; //7 &nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;//exit; &nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;//var_export($this); //StringHelper::__set_state(array( 'value' =&gt; 7, )) &nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;//exit; &nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;return $this; &nbsp;&nbsp; &nbsp;} } 
 $str = " sd f 0"; $str = new StringHelper($str); echo $str-&gt;trim('0')-&gt;strlen(); &nbsp;//输出 6 echo "&lt;br&gt;"; echo $str-&gt;strlen()-&gt;trim('0'); // 输出 1 
 </blockquote> 输出: <img alt="" height="127" src="https://img-blog.csdnimg.cn/20200321224424642.png" width="368"> &nbsp; &nbsp; 2.2 自定义函数/方法的链式调用[框架中使用] TBD &nbsp; &nbsp; 总结: 链式调用本质, 是每次执行调用者都是对象. 只要查看详情即可知道有哪些方法, 从而执行相应操作. &nbsp; &nbsp; 后续补充 ... </td> 
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3.问题/补充

4.参考

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 <td> <a href="https://www.jb51.net/article/103836.htm" rel="nofollow">https://www.jb51.net/article/103836.htmhttps://www.jb51.net/article/103836.htm&nbsp; //</a>PHP三种方式实现链式操作详解 <a href="https://www.php.cn/php-weizijiaocheng-395865.html" rel="nofollow">https://www.php.cn/php-weizijiaocheng-395865.html</a>&nbsp; //PHP 中__call()的使用方法 <a href="https://www.php.cn/php-weizijiaocheng-390011.html" rel="nofollow">https://www.php.cn/php-weizijiaocheng-390011.html</a>&nbsp; //PHP中__call()和__callStatic()使用方法 <a href="https://www.php.net/manual/zh/function.call-user-func.php" rel="nofollow">https://www.php.net/manual/zh/function.call-user-func.php</a>&nbsp; //call_user_func <a href="https://www.php.net/manual/zh/function.call-user-func-array.php" rel="nofollow">https://www.php.net/manual/zh/function.call-user-func-array.php</a>&nbsp; //call_user_func_array <a href="https://www.php.net/manual/zh/language.oop5.magic.php" rel="nofollow">https://www.php.net/manual/zh/language.oop5.magic.php</a>&nbsp; //魔术方法 <a href="https://www.php.net/manual/zh/language.oop5.overloading.php#object.call" rel="nofollow">https://www.php.net/manual/zh/language.oop5.overloading.php#object.call</a>&nbsp; // __call 与 __callStatic方法重载 <a href="https://www.php.net/manual/zh/language.oop5.magic.php#object.tostring" rel="nofollow">https://www.php.net/manual/zh/language.oop5.magic.php#object.tostring</a>&nbsp; //__toString <a href="https://www.cnblogs.com/-simon/p/5875128.html" rel="nofollow">https://www.cnblogs.com/-simon/p/5875128.html</a>&nbsp; //PHP实现链式操作的原理 <a href="https://www.cnblogs.com/yangtoude/p/php-simple-chain-operation-implementation.html" rel="nofollow">https://www.cnblogs.com/yangtoude/p/php-simple-chain-operation-implementation.html</a>&nbsp; //用php实现一个简单的链式操作 &nbsp; &lt;&lt;PHP核心技术与最佳实践&gt;&gt; -- Page 9&nbsp; //之前读, 没看明白, 现在倒是看懂了些. 有些书还是要多读, 多实践 </td> 
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后续补充

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