如何用pathinfo 判斷文件類型並執行不同PHP 操作邏輯？

gitbox 2025-09-08
<span><span><span class="hljs-meta">&lt;?php</span></span><span>
</span><span><span class="hljs-comment">// 這部分代碼無關正文內容，只是示例展示，實際應用可根據需要調整</span></span><span>
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"程序開始執行&lt;br&gt;"</span></span><span>;
</span><span><span class="hljs-meta">?&gt;</span></span><span>

&lt;hr&gt;

</span><span><span class="hljs-meta">&lt;?php</span></span><span>
<span class="hljs-comment">/**
 * 如何用 pathinfo 判斷文件類型並執行不同 PHP 操作邏輯？
 * 
 * 在PHP開發中，常常需要根據文件的類型執行不同的處理邏輯，比如圖片文件、文檔文件、視頻文件等。
 * PHP內置的 pathinfo 函數可以方便地獲取文件路徑的信息，包括文件擴展名，從而實現對文件類型的判斷。
 * 
 * 以下是一個簡單示例，演示如何使用 pathinfo 獲取文件擴展名，並根據不同類型執行不同的操作。
 */</span>

</span><span><span class="hljs-comment">// 假設有一個文件名</span></span><span>
</span><span><span class="hljs-variable">$filename</span></span><span> = </span><span><span class="hljs-string">"example.jpg"</span></span><span>;

</span><span><span class="hljs-comment">// 使用 pathinfo 獲取文件信息</span></span><span>
</span><span><span class="hljs-variable">$fileInfo</span></span><span> = </span><span><span class="hljs-title function_ invoke__">pathinfo</span></span><span>(</span><span><span class="hljs-variable">$filename</span></span><span>);

</span><span><span class="hljs-comment">// 獲取擴展名（注意轉成小寫，避免擴展名大小寫不一致問題）</span></span><span>
</span><span><span class="hljs-variable">$extension</span></span><span> = </span><span><span class="hljs-title function_ invoke__">strtolower</span></span><span>(</span><span><span class="hljs-variable">$fileInfo</span></span><span>[</span><span><span class="hljs-string">'extension'</span></span><span>] ?? </span><span><span class="hljs-string">''</span></span><span>);

</span><span><span class="hljs-comment">// 根據擴展名執行不同邏輯</span></span><span>
</span><span><span class="hljs-keyword">switch</span></span><span> (</span><span><span class="hljs-variable">$extension</span></span><span>) {
    </span><span><span class="hljs-keyword">case</span></span><span> </span><span><span class="hljs-string">'jpg'</span></span><span>:
    </span><span><span class="hljs-keyword">case</span></span><span> </span><span><span class="hljs-string">'jpeg'</span></span><span>:
    </span><span><span class="hljs-keyword">case</span></span><span> </span><span><span class="hljs-string">'png'</span></span><span>:
    </span><span><span class="hljs-keyword">case</span></span><span> </span><span><span class="hljs-string">'gif'</span></span><span>:
        </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"這是一個圖片文件，執行圖片處理邏輯。&lt;br&gt;"</span></span><span>;
        </span><span><span class="hljs-comment">// 這裡可以寫圖片相關的處理代碼，比如縮略圖生成、圖片壓縮等</span></span><span>
        </span><span><span class="hljs-keyword">break</span></span><span>;

    </span><span><span class="hljs-keyword">case</span></span><span> </span><span><span class="hljs-string">'pdf'</span></span><span>:
    </span><span><span class="hljs-keyword">case</span></span><span> </span><span><span class="hljs-string">'doc'</span></span><span>:
    </span><span><span class="hljs-keyword">case</span></span><span> </span><span><span class="hljs-string">'docx'</span></span><span>:
        </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"这是一个文檔文件，執行文檔處理邏輯。&lt;br&gt;"</span></span><span>;
        </span><span><span class="hljs-comment">// 這裡可以寫文檔相關的處理代碼，比如內容解析、格式轉換等</span></span><span>
        </span><span><span class="hljs-keyword">break</span></span><span>;

    </span><span><span class="hljs-keyword">case</span></span><span> </span><span><span class="hljs-string">'mp4'</span></span><span>:
    </span><span><span class="hljs-keyword">case</span></span><span> </span><span><span class="hljs-string">'avi'</span></span><span>:
    </span><span><span class="hljs-keyword">case</span></span><span> </span><span><span class="hljs-string">'mov'</span></span><span>:
        </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"這是一個視頻文件，執行視頻處理邏輯。&lt;br&gt;"</span></span><span>;
        </span><span><span class="hljs-comment">// 這裡可以寫視頻相關的處理代碼，比如轉碼、提取封面等</span></span><span>
        </span><span><span class="hljs-keyword">break</span></span><span>;

    </span><span><span class="hljs-keyword">default</span></span><span>:
        </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"未知或不支持的文件類型，執行默認處理邏輯。&lt;br&gt;"</span></span><span>;
        </span><span><span class="hljs-comment">// 這裡寫默認處理邏輯，比如拒絕上傳、提示錯誤等</span></span><span>
        </span><span><span class="hljs-keyword">break</span></span><span>;
}

<span class="hljs-comment">/**
 * 這里特別注意：
 * 1. pathinfo 只解析文件名字符串本身，不驗證文件是否存在。
 * 2. 擴展名判斷依賴文件名後綴，可能存在安全風險（比如惡意更改後綴），必要時應結合 mime_content_type 等方式進行二次驗證。
 * 3. 擴展名應轉換為統一格式（一般用 strtolower）來避免大小寫導致判斷失誤。
 */</span>

</span><span><span class="hljs-meta">?&gt;</span></span><span>
</span></span>
pathinfo