导入hutool maven依赖

<dependency><groupId>cn.hutool</groupId><artifactId>hutool-all</artifactId><version>5.8.16</version>
</dependency>

下载文件controller代码片段
@GetMapping(“/pics/{path}”)
public ResponseEntity<byte[]> getFile(@PathVariable(“path”) Long path) {
try {

        File file = FileUtil.file(path);if (file.exists() && file.canRead()) {byte[] fileContent = FileUtil.readBytes(file);return ResponseEntity.ok().header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + path + "\"").header(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_OCTET_STREAM_VALUE).body(fileContent);} else {return ResponseEntity.notFound().build();}} catch (Exception e) {return ResponseEntity.badRequest().build();}
}