如何使用feof配合ob_flush和flush函數實現大文件的分段輸出？

<span><span><span class="hljs-meta"><?php</span></span><span>
</span><span><span class="hljs-comment">// 以下部分與文章內容無關，僅為示例前置代碼</span></span><span>
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</span><span><span class="hljs-title function_ invoke__">date_default_timezone_set</span></span><span>(</span><span><span class="hljs-string">'Asia/Shanghai'</span></span><span>);
</span><span><span class="hljs-title function_ invoke__">ob_start</span></span><span>();
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</span><span><span class="hljs-meta"><?php</span></span><span>
</span><span><span class="hljs-comment">// 正文開始</span></span><span>
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<h1>如何使用feof配合ob_flush和flush函數實現大文件的分段輸出？</h1>"</span></span><span>;

</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<p>在處理大文件下載或者生成大文件內容時，如果一次性將整個文件內容輸出到瀏覽器，容易導致PHP內存溢出或網頁長時間無響應。為了避免這種情況，可以採用分段輸出的方式，即每次輸出一部分內容，然後刷新緩衝區，讓瀏覽器逐步接收到數據。</p>"</span></span><span>;

</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<h2>關鍵函數說明</h2>"</span></span><span>;
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<ul>"</span></span><span>;
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<li><strong>feof(resource <span class="hljs-subst">$handle</span></span></span><span>)</strong>：檢查文件指針是否到達文件末尾。如果到達末尾返回 true，否則返回 false。</li>";
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<li><strong>ob_flush()</strong>：將 PHP 的輸出緩衝區內容髮送到瀏覽器，並清空緩衝區（需要開啟緩衝區）。</li>"</span></span><span>;
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<li><strong>flush()</strong>：强制將服务器缓冲区中的内容发送到浏览器，使瀏覽器立即顯示輸出。</li>"</span></span><span>;
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"</ul>"</span></span><span>;

</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<h2>實現思路</h2>"</span></span><span>;
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<ol>"</span></span><span>;
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<li>打開要輸出的文件，並判斷是否成功。</li>"</span></span><span>;
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<li>循環讀取文件內容，可以按行或者按固定字節數讀取。</li>"</span></span><span>;
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<li>在每次讀取輸出後，調用 <code>ob_flush()