Java文件上傳下載

/**
 * 上傳文件
 */
public String uploadFile() throws IOException, Exception {
    
    if (getRequestContext().haveUploadFile()) {

        String channelId = getRequest().getParameter("channelId");
        JfileItem fileItem = getRequestContext().getUploadFiles().get(0);

        // 文件名
        String fileName = fileItem.getName();
        DateFormat df = new SimpleDateFormat("yyyyMMddHHmmssSSS");
        String uploadFileName = df.format(new Date()) + fileName;

        // 文件類型
        int n = fileName.lastIndexOf(".");
        String type = fileName.substring(n + 1);

        // 上傳路徑
        String path = getRequest().getServletContext().getRealPath("") + "\\uploadfiles\\";

        //獲取輸出流
        OutputStream os = new FileOutputStream(path + uploadFileName);
        
        // 獲得輸入流
        InputStream is = fileItem.getInputStream();
        
        // 寫入
        byte[] buffer = new byte[512];
        int temp;
        while ((temp = is.read(buffer)) != (-1)) {
            os.write(buffer, 0, temp);
        }
        os.flush();
        os.close();
        is.close();

        // 將文件信息寫入數據庫
        FileUpload fileUpload = new FileUpload();
        fileUpload.setFileName(fileName);
        fileUpload.setFileLocation(uploadFileName);
        fileUpload.setFileChannelId(channelId);
        fileUploadService.save(fileUpload);
    }
    return getOutJson().toString();
}

/**
 * 下載文件
 */
public String downloadFile() throws Exception {

    String id = getRequest().getParameter("id");
    FileUpload fileUpload = fileUploadService.getById(id);

    // 根路徑
    String path = getRequest().getServletContext().getRealPath("") + "\\uploadfiles\\";

    // 下載文件的路徑
    String filePath = path + fileUpload.getFileLocation();

    // 文件名
    String fileName = fileUpload.getFileName();
    fileName = URLEncoder.encode(fileName, "UTF-8");

    HttpServletResponse response = getResponse();

    // 設置文件ContentType類型，自動判斷下載文件類型
    response.setContentType("multipart/form-data");
    // 設置編碼
    response.setCharacterEncoding("utf-8");
    // 設置文件頭，最後一個參數是設置下載文件名
    response.setHeader("Content-Disposition", "attachment;fileName=" + fileName);

    // 通過文件路徑獲得File對象
    File file = new File(filePath);

    FileInputStream is = new FileInputStream(file);

    // 通過response獲取OutputStream對象
    OutputStream os = response.getOutputStream();

    // 寫入
    byte[] buffer = new byte[512];
    int i;
    while ((i = is.read(buffer)) != -1) {
        os.write(buffer, 0, i);
    }
    os.flush();
    os.close();
    is.close();

    return getOutJson().toString();
}
 

Java文件上傳下載