Spring boot 簡單的圖片反向代理

jerry80409

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2 min read

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May 15, 2020

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反向代理的好處

1. 保護 Server 跟 Resource
2. 可在代理上作快取, Loadbalance, 優化資源存取速度
3. 節約 IP 的使用, 或做一些 URL 的管理, 短網址, 短連結…

Sample Code

@GetMapping(value = "/image", produces = MediaType.IMAGE_JPEG_VALUE)
public ResponseEntity<byte[]> image() throws Exception {
  URL url = new URL("圖片 URL");
  URLConnection connection = url.openConnection();
  connection.setRequestProperty("User-Agent", "Mozilla/5.0 (X11; Linux x86_64) ...");
  BufferedImage image = ImageIO.read(connection.getInputStream());
  ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
  ImageIO.write(image, "jpg", outputStream);

  HttpHeaders header = new HttpHeaders();
  header.add(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=img.jpg");
  return ResponseEntity.ok()
      .headers(header)
      .body(outputStream.toByteArray());
}