使用Spring以Base64字符串的形式返回图片和PDF

import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.util.Base64Utils;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;

@RestController
@RequestMapping("/image-pdf")
public class ImagePdfController {

    @GetMapping("/image")
    public ResponseEntity<String> getImageAsBase64() throws IOException {
        File imageFile = new File("path/to/image.jpg");
        byte[] imageBytes = new byte[(int) imageFile.length()];
        FileInputStream fis = new FileInputStream(imageFile);
        fis.read(imageBytes);
        fis.close();

        String base64Image = Base64Utils.encodeToString(imageBytes);

        return ResponseEntity.ok(base64Image);
    }

    @GetMapping("/pdf")
    public ResponseEntity<String> getPdfAsBase64() throws IOException {
        File pdfFile = new File("path/to/file.pdf");
        byte[] pdfBytes = new byte[(int) pdfFile.length()];
        FileInputStream fis = new FileInputStream(pdfFile);
        fis.read(pdfBytes);
        fis.close();

        String base64Pdf = Base64Utils.encodeToString(pdfBytes);

        return ResponseEntity.ok(base64Pdf);
    }
}