spring boot 返回文件流

所需依赖

    org.springframework.boot
    spring-boot-starter-web

完整的Controller代码

import org.springframework.core.io.InputStreamResource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

@Controller
public class FileDownloadController {

    @GetMapping("/download")
    @ResponseBody
    public ResponseEntity downloadFile() throws IOException {
        File file = new File("实际的文件路径");
        InputStream inputStream = new FileInputStream(file);
        InputStreamResource resource = new InputStreamResource(inputStream);

        HttpHeaders headers = new HttpHeaders();
        headers.add(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=实际的文件名");

        return ResponseEntity.ok()
                .headers(headers)
                .contentLength(file.length())
                .contentType(MediaType.APPLICATION_OCTET_STREAM)
                .body(resource);
    }
}