fgetss處理大文件時會卡頓？教你幾招優化性能的方法

<span><span><span class="hljs-meta"><?php</span></span><span>
</span><span><span class="hljs-comment">// 這裡是與文章內容無關的PHP代碼示例</span></span><span>
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"歡迎閱讀本文！<br>"</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>fgetss處理大文件時會卡頓？教你幾招優化性能的方法</h1>"</span></span><span>;

</span><span><span class="hljs-comment">// 引言</span></span><span>
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<p>在PHP開發中，fgetss函數常用於從文件中逐行讀取內容並去除HTML標籤，但在處理大文件時，很多開發者會遇到明顯的卡頓現象。本文將分析卡頓原因，並提供幾種優化性能的方法。</p>"</span></span><span>;

</span><span><span class="hljs-comment">// 一、理解fgetss的工作原理</span></span><span>
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<h2>一、理解fgetss的工作原理</h2>"</span></span><span>;
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<p>fgetss函數的核心是逐行讀取文件內容，同時去掉HTML和PHP標籤。如果文件很大，每次調用fgetss都需要执行字符串解析和標籤过滤，這會帶來不小的性能開銷。</p>"</span></span><span>;

</span><span><span class="hljs-comment">// 二、大文件卡頓的原因</span></span><span>
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<h2>二、大文件卡頓的原因</h2>"</span></span><span>;
</span><span><span class="hljs-keyword">echo</span></span><span> <span class="hljs-string">"<ul>
<li><strong>文件太大：</strong>一次性讀取整個文件會佔用大量內存。</li>
<li><strong>頻繁I/O操作：</strong>每次fgetss調用都要訪問硬盤，I/O是性能瓶頸。</li>
<li><strong>標籤解析开销：</strong>fgetss會解析並去除HTML標籤，這在大文本中耗時明顯。</li>
</ul>"</span>;

</span><span><span class="hljs-comment">// 三、優化方法</span></span><span>
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<h2>三、優化方法</h2>"</span></span><span>;

</span><span><span class="hljs-comment">// 方法1：使用fgets+strip_tags替代fgetss</span></span><span>
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<h3>1. 使用 <code>fgets

\$bufferSize = 8192; // 默認4096，可增大\$handle = fopen('largefile.txt', 'r');
while (!feof(\$handle)) {
    \$line = fgetss(\$handle, \$bufferSize);
    // 處理\$line
}
fclose(\$handle);

\$handle = fopen('largefile.txt', 'r');
\$chunkSize = 16384;
while (!feof(\$handle)) {
    \$chunk = fread(\$handle, \$chunkSize);
    \$cleanChunk = strip_tags(\$chunk);
    // 處理\$cleanChunk
}
fclose(\$handle);

function readFileLines(\$file) {
    \$handle = fopen(\$file, 'r');
    if (!\$handle) return;
    while (!feof(\$handle)) {
        yield strip_tags(fgets(\$handle));
    }
    fclose(\$handle);
}

foreach (readFileLines('largefile.txt') as \$line) {
    // 處理\$line
}