使用spring控制器处理文件

我需要：通过

@Controller

从我的文件系统下载或显示内联文件

我找到了好几种方法。但是，我不知道哪一个更好

我在读这样的文件：

public static byte[] readFileAsByteArray(String fileName) {
   ...
   return Files.readAllBytes(Paths.get(fileName));
   ...
}

方法1（效果良好）：

@RequestMapping(value = "/help/manual")
public ResponseEntity<byte[]> getUsersManual() {
    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.parseMediaType("application/pdf"));
    headers.add("content-disposition", "inline;filename=" + MANUAL_FILE);
    headers.setCacheControl("must-revalidate, post-check=0, pre-check=0");
    byte[] fileBytes = FileUtils.readFileAsByteArray(MANUAL_FILE);
    ResponseEntity<byte[]> response = new ResponseEntity<>(fileBytes, headers, HttpStatus.OK);
    return response;
}

@RequestMapping(value = "/help/manual1")
public void getUsersManual1(HttpServletResponse response) throws IOException {
    ServletOutputStream outputStream = response.getOutputStream();
    response.setContentType("application/pdf");
    response.addHeader("content-disposition", "inline;filename=" + MANUAL_FILE);
    outputStream.write(FileUtils.readFileAsByteArray(MANUAL_FILE));
    outputStream.flush();
    outputStream.close();
}

@RequestMapping(value = "/help/manual2")
@ResponseBody
public FileSystemResource getUsersManual2(HttpServletResponse response) {
    File file = new File(MANUAL_FILE);
    response.setContentType("application/octet-stream");
    response.setHeader("Content-Disposition", "attachment; filename=" + file.getName());
    response.setHeader("Content-Length", String.valueOf(file.length()));
    return new FileSystemResource(file);
}

方法3（仅适用于“应用程序/八位字节流”和附件）：

@RequestMapping(value = "/help/manual")
public ResponseEntity<byte[]> getUsersManual() {
    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.parseMediaType("application/pdf"));
    headers.add("content-disposition", "inline;filename=" + MANUAL_FILE);
    headers.setCacheControl("must-revalidate, post-check=0, pre-check=0");
    byte[] fileBytes = FileUtils.readFileAsByteArray(MANUAL_FILE);
    ResponseEntity<byte[]> response = new ResponseEntity<>(fileBytes, headers, HttpStatus.OK);
    return response;
}

@RequestMapping(value = "/help/manual1")
public void getUsersManual1(HttpServletResponse response) throws IOException {
    ServletOutputStream outputStream = response.getOutputStream();
    response.setContentType("application/pdf");
    response.addHeader("content-disposition", "inline;filename=" + MANUAL_FILE);
    outputStream.write(FileUtils.readFileAsByteArray(MANUAL_FILE));
    outputStream.flush();
    outputStream.close();
}

@RequestMapping(value = "/help/manual2")
@ResponseBody
public FileSystemResource getUsersManual2(HttpServletResponse response) {
    File file = new File(MANUAL_FILE);
    response.setContentType("application/octet-stream");
    response.setHeader("Content-Disposition", "attachment; filename=" + file.getName());
    response.setHeader("Content-Length", String.valueOf(file.length()));
    return new FileSystemResource(file);
}

那么，在

@Controller

中处理文件的最佳方法是什么

我使用：

• 弹簧靴1.5.9
• 春季4.3.13

---

谢谢。

我更喜欢方法2稍加修改。
如果文件大小很大，例如几GB，会发生什么。
因此，您应该使用

InputStream

读取该文件，并将其写入servlet

OutputStream

。否则，由于堆空间的原因，您可能会捕获到

outOfMemoryException

@RequestMapping(value = "/help/manual1")
public void getUsersManual1(HttpServletResponse response) throws IOException {

    String MANUAL_FILE="yourfileName";
    int BUFFER_SIZE = 4096;
    // the complete absolute path of the file
    String fullPath = "path\\to\\your\\file";
    File downloadableFile = new File(fullPath);
    FileInputStream inputStream = new FileInputStream(downloadableFile);

    ServletOutputStream outputStream = response.getOutputStream();
    response.setContentType("application/pdf");
    response.addHeader("content-disposition", "inline;filename=" + MANUAL_FILE);
    response.setContentLength((int) downloadableFile.length());

    byte[] buffer = new byte[BUFFER_SIZE];
    int bytesRead = -1;

    // we need to write the bytes which we read from inputStream
    while ((bytesRead = inputStream.read(buffer)) != -1) {
        outputStream.write(buffer, 0, bytesRead);
    }

    outputStream.flush();
    outputStream.close();
    inputStream.close();
}

---

我更喜欢方法2，稍加修改。
如果文件大小很大，例如几GB，会发生什么。
因此，您应该使用

InputStream

读取该文件，并将其写入servlet

OutputStream

。否则，由于堆空间的原因，您可能会捕获到

outOfMemoryException

@RequestMapping(value = "/help/manual1")
public void getUsersManual1(HttpServletResponse response) throws IOException {

    String MANUAL_FILE="yourfileName";
    int BUFFER_SIZE = 4096;
    // the complete absolute path of the file
    String fullPath = "path\\to\\your\\file";
    File downloadableFile = new File(fullPath);
    FileInputStream inputStream = new FileInputStream(downloadableFile);

    ServletOutputStream outputStream = response.getOutputStream();
    response.setContentType("application/pdf");
    response.addHeader("content-disposition", "inline;filename=" + MANUAL_FILE);
    response.setContentLength((int) downloadableFile.length());

    byte[] buffer = new byte[BUFFER_SIZE];
    int bytesRead = -1;

    // we need to write the bytes which we read from inputStream
    while ((bytesRead = inputStream.read(buffer)) != -1) {
        outputStream.write(buffer, 0, bytesRead);
    }

    outputStream.flush();
    outputStream.close();
    inputStream.close();
}

---

您曾写道希望通过@Controller实现这一点，但您是否考虑过spring ResourceHandler，它是spring提供静态资源的最佳方式

以下是一个例子：

---

您曾写道希望通过@Controller实现这一点，但您是否考虑过spring ResourceHandler，它是spring提供静态资源的最佳方式

以下是一个例子：

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