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Spring MCV-文件下载

  • 2019年 05月05日

在 springmvc 应用程序中下载文件有几种方法:

  1. HttpServletRespone: 使用 HttpServletResponse 将文件直接写入 ServletOutputStream
  2. ResponseEntity<InputStreamResource>: 返回包装在 ResponseEntity 中的 InputStreamResource 文件
  3. ResponseEntity<ByteArrayResource>: 可以返回包装在 ResponseEntity 中的 ByteArrayResource 文件

HttpServletRespone

@GetMapping("/download")
public void download(HttpServletResponse resonse) {
    try{
        // get file as InputStream
        InputStream is=...;
        // copy it to response's OutputStream
        org.apache.commons.io.IOUtils.copy(is,response.getOutputStream());
        response.flushBuffer();
    }catch(IOException ex){
        log.info("Error writing file to output stream. Filename was '{}'",fileName,ex);
        throw new RuntimeException("IOError writing file to output stream");
    }
}

ResponseEntity<InputStreamResource>

Resource implementation for a given InputStream. Should only be used if no other specific Resource implementation is > applicable. In particular, prefer ByteArrayResource or any of the file-based Resource implementations where possible.

@GetMapping("/download")
public ResponseEntity<InputStreamResource> download() throw FileNotFoundException {
	File file = service.generateFile();
	InputStreamResource resource = new InputStreamResource(new FileInputStream(file));
	return ResponseEntity.ok()
			.header(HttpHeaders.CONTENT_DISPOSITION, "attachment;filename=" + file.getName())
			.contentType(MediaType.TEXT_PLAIN) // or others
			.contentLength(file.length())
			.body(resource);
}

ByteArrayResource

InputStreamResource 的文档建议使用 ByteArrayResource

@GetMapping(path = "/download")
public ResponseEntity<Resource> download(String param) throws IOException {
    File file = // get file
    Path path = Paths.get(file.getAbsolutePath());
    ByteArrayResource resource = new ByteArrayResource(Files.readAllBytes(path));

    return ResponseEntity.ok()
            .headers(HttpHeaders.CONTENT_DISPOSITION, "attachment;filename=" + file.getName())
            .contentLength(file.length())
            .contentType(MediaType.APPLICATION_OCTET_STREAM)
            .body(resource);
}

参考

https://www.boraji.com/spring-mvc-4-file-download-example?tdsourcetag=s_pcqq_aiomsg https://stackoverflow.com/questions/5673260/downloading-a-file-from-spring-controllers

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