文件读取与查看

一、读取
　　

public String setFileName() {
    StringBuilder strFile = new StringBuilder();
    String filePath = "你的路径";
    File directory = new File(filePath);

    // 确保路径确实指向一个目录
    if (directory.exists() && directory.isDirectory()) {
        // 获取目录下的所有文件和子目录
        File[] files = directory.listFiles();

        if (files != null) {
            for (File file1 : files) {
                strFile.append(file1.getName()+",");
            }
        } else {
            logger.error("该目录下没有文件或子目录");
        }
    } else {
        logger.error("路径不是一个有效的目录或者不存在");
    }
　　return strFile.toString();

}

二、查看

1、
@RequestMapping(value = "/view/{filename}", method = RequestMethod.GET)
public void downloadReadOnlyFile(@PathVariable String filename，
                                 HttpServletResponse response) throws Exception {

　　 String filePath = "路径"；

    File file = new File(filePath + fileName);
    file.setReadOnly();//只读

    if (!file.exists()) {
        throw new FileNotFoundException(filename);
    }
    // 设置响应头 动态设置Content-Type
    Path filePathOne = Paths.get(filePath, filename);
    MediaType mediaType = MediaType.valueOf(Files.probeContentType(filePathOne));
    response.setContentType(String.valueOf(mediaType));

    response.setHeader("Content-Disposition", "inline; filename=\"" + file.getName() + "\"");//inline浏览器打开，attachment下载
    response.setHeader("Content-Transfer-Encoding", "binary");
    response.setHeader("Pragma", "no-cache");
    response.setHeader("Expires", "0");

    try {
        FileInputStream inputStream = new FileInputStream(file);// 打开文件输入流
        ServletOutputStream outputStream = response.getOutputStream();// 获取输出流
        // 复制文件内容到响应输出流
        byte[] buffer = new byte[4096];
        int bytesRead;
        while ((bytesRead = inputStream.read(buffer)) != -1) {
            outputStream.write(buffer, 0, bytesRead);
        }
        // 关闭流
        outputStream.flush();
        outputStream.close();
        inputStream.close();
    } catch (IOException e) {
        response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
        // 可以记录日志或者进行其他错误处理
    }
}

2、

@RequestMapping(value = "/view/{type}/{filename}", method = RequestMethod.GET)
public ResponseEntity<FileSystemResource> viewFile(@PathVariable String filename, @PathVariable String type) throws IOException {

    String filePath = "D:/";

    Path filePathOne = Paths.get(filePath, filename+"."+type);
    FileSystemResource file = new FileSystemResource(filePathOne.toString());
    if (!file.exists()) {
        return new ResponseEntity<FileSystemResource>(HttpStatus.NOT_FOUND);
    }

    // 动态设置Content-Type
    MediaType mediaType = MediaType.valueOf(Files.probeContentType(filePathOne));

    return ResponseEntity.ok()
            .header(HttpHeaders.CONTENT_DISPOSITION, "inline; filename=\"" + file.getFilename() + "\"")
            .contentType(mediaType) // 或者根据文件类型动态设置
            .body(file);
}