```java
public static Mat readHttpImage(String url) throws IOException {
// 讀取 URL 並轉換為 InputStream
URL imageUrl = new URL(url);
InputStream stream = imageUrl.openStream();
// 將 InputStream 轉換為 byte[]
byte[] bytes = stream.readAllBytes();
// 將 byte[] 轉換為 Mat
Mat image = Imgcodecs.imdecode(new MatOfByte(bytes), Imgcodecs.IMREAD_UNCHANGED);
return image;
}
```