Content API

Content 模組提供檔案內容類型（MIME Type）檢測功能。

套件: io.leandev.appfuse.content

核心類別

ContentDetector

內容類型檢測器。

public class ContentDetector {
    MediaType detect(Path path) throws IOException
    MediaType detect(InputStream input) throws IOException
    MediaType detect(byte[] bytes) throws IOException
}

使用範例

從檔案路徑檢測

ContentDetector detector = new ContentDetector();

Path imagePath = Paths.get("/uploads/photo.jpg");
MediaType mediaType = detector.detect(imagePath);

System.out.println(mediaType.toString());  // image/jpeg

從 InputStream 檢測

ContentDetector detector = new ContentDetector();

try (InputStream input = new FileInputStream(file)) {
    MediaType mediaType = detector.detect(input);

    if (mediaType.getType().equals("image")) {
        // 處理圖片
    }
}

從 byte[] 檢測

ContentDetector detector = new ContentDetector();

byte[] fileContent = Files.readAllBytes(path);
MediaType mediaType = detector.detect(fileContent);

String mimeType = mediaType.toString();

搭配檔案上傳

@PostMapping("/upload")
public ResponseEntity<?> upload(@RequestParam MultipartFile file) {
    ContentDetector detector = new ContentDetector();

    try {
        MediaType mediaType = detector.detect(file.getInputStream());

        // 驗證檔案類型
        if (!isAllowedType(mediaType)) {
            return ResponseEntity.badRequest().body("Invalid file type");
        }

        // 儲存檔案...
    } catch (IOException e) {
        return ResponseEntity.internalServerError().build();
    }
}

private boolean isAllowedType(MediaType mediaType) {
    return mediaType.getType().equals("image") ||
           mediaType.toString().equals("application/pdf");
}

支援的 MIME 類型

圖片

副檔名	MIME Type
jpg, jpeg	image/jpeg
png	image/png
gif	image/gif
webp	image/webp
bmp	image/bmp
svg	image/svg+xml
ico	image/x-icon
tiff	image/tiff
avif	image/avif
heic, heif	image/heic

文檔

副檔名	MIME Type
pdf	application/pdf
txt	text/plain
csv	text/csv
xml	application/xml
json	application/json
md	text/markdown

Office

副檔名	MIME Type
doc	application/msword
docx	application/vnd.openxmlformats-officedocument.wordprocessingml.document
xls	application/vnd.ms-excel
xlsx	application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
ppt	application/vnd.ms-powerpoint
pptx	application/vnd.openxmlformats-officedocument.presentationml.presentation

壓縮

副檔名	MIME Type
zip	application/zip
gz	application/gzip
tar	application/x-tar
7z	application/x-7z-compressed
rar	application/vnd.rar

網頁

副檔名	MIME Type
html, htm	text/html
css	text/css
js	text/javascript
ts	text/typescript
jsx, tsx	text/javascript

多媒體

副檔名	MIME Type
mp4	video/mp4
avi	video/x-msvideo
mov	video/quicktime
webm	video/webm
mp3	audio/mpeg
wav	audio/wav
ogg	audio/ogg

檢測策略

ContentDetector 使用混合策略檢測 MIME 類型：

1. Java NIO - Files.probeContentType()
2. 魔術位元組 - URLConnection.guessContentTypeFromStream()
3. 副檔名映射 - 內建副檔名對照表

異常處理

ContentException

try {
    MediaType mediaType = detector.detect(path);
} catch (ContentException e) {
    // 檢測失敗
    log.error("Failed to detect content type: {}", e.getMessage());
} catch (IOException e) {
    // IO 錯誤
    log.error("IO error: {}", e.getMessage());
}

最佳實踐

1. 驗證上傳檔案 - 不要只信任副檔名，檢測實際內容
2. 白名單驗證 - 只允許預期的 MIME 類型
3. 處理檢測失敗 - 未知類型預設為 application/octet-stream

相關連結

• Content 使用指南
• Javadoc