spring boot中文件下载方法

 

使用HttpServletResponse，

1、转成StreamingResponseBody写入HttpServletResponse

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@GetMapping("/downloadFile") public void downloadFile(HttpServletResponse response) throws IOException {     // 设置响应头，指定文件名     response.setHeader("Content-Disposition", "attachment; filename=file.txt");       // 获取文件输入流     InputStream inputStream = new FileInputStream("path/to/file.txt");       // 创建StreamingResponseBody对象，将文件内容写入响应输出流     StreamingResponseBody responseBody = outputStream -> {         byte[] buffer = new byte[1024];         int bytesRead;         while ((bytesRead = inputStream.read(buffer)) != -1) {             outputStream.write(buffer, 0, bytesRead);         }         inputStream.close();     };       // 返回StreamingResponseBody对象     response.setContentType(MediaType.APPLICATION_OCTET_STREAM_VALUE);     responseBody.writeTo(response.getOutputStream()); }

2、转成Bytes写入HttpServletResponse

@GetMapping("/downloadFiles")
public void downloadFile(HttpServletResponse response) throws IOException {

    byte[] data = Files.readAllBytes(Paths.get("D:\\file.txt"));
    // 设置响应头，指定文件名
    response.reset();
    response.setHeader("Content-Disposition", "attachment; filename=file.txt");
    response.addHeader("Content-Length", "" + data.length);
    response.setContentType(MediaType.APPLICATION_OCTET_STREAM_VALUE);
    response.getOutputStream().write(data);
}

　使用ResponseEntity类：

1、转成Bytes写入ResponseEntity

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@GetMapping("/downloadFile") public ResponseEntity<byte[]> downloadFile() throws IOException {     // 读取文件内容到字节数组     byte[] fileContent = Files.readAllBytes(Paths.get("path/to/file.txt"));       // 设置响应头，指定文件名     HttpHeaders headers = new HttpHeaders();     headers.setContentDisposition(ContentDisposition.attachment().filename("file.txt").build());       // 返回文件内容和响应头     return ResponseEntity.ok().headers(headers).body(fileContent); }

2、转成Resource写入ResponseEntity

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@GetMapping("/downloadFile") public ResponseEntity<Resource> downloadFile() {     // 创建Resource对象，表示文件路径     Resource fileResource = new FileSystemResource("path/to/file.txt");       // 设置响应头，指定文件名     HttpHeaders headers = new HttpHeaders();     headers.setContentDisposition(ContentDisposition.attachment().filename("file.txt").build());       // 返回文件资源和响应头     return ResponseEntity.ok().headers(headers).body(fileResource); }

3、转成InputStreamResource写入ResponseEntity

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@GetMapping("/downloadFile") public ResponseEntity<InputStreamResource> downloadFile() throws FileNotFoundException {     // 创建文件输入流     FileInputStream fileInputStream = new FileInputStream("path/to/file.txt");       // 创建InputStreamResource对象，封装文件输入流     InputStreamResource resource = new InputStreamResource(fileInputStream);       // 设置响应头，指定文件名     HttpHeaders headers = new HttpHeaders();     headers.setContentDisposition(ContentDisposition.attachment().filename("file.txt").build());       // 返回InputStreamResource对象和响应头     return ResponseEntity.ok().headers(headers).body(resource); }

　4、转成ByteArrayResource写入ResponseEntity

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@GetMapping("/downloadFiles") public ResponseEntity<ByteArrayResource> downloadFile() throws IOException {     // 读取文件内容到字节数组     byte[] fileContent = Files.readAllBytes(Paths.get("D:\\file.txt"));     ByteArrayResource resource = new ByteArrayResource(fileContent);     // 设置响应头，指定文件名     HttpHeaders headers = new HttpHeaders();     headers.setContentDisposition(ContentDisposition.attachment().filename("file9.txt").build());       // 返回文件内容和响应头     return new ResponseEntity<>(resource, headers, HttpStatus.OK); }