JavaWeb09-Servlet实现下载文件

DownloadServlet

public class DownloadServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//        String realPath = this.getServletContext().getRealPath("");获取本地文件路径，前提在此目录下确实存在这个文件
        String realPath = this.getServletContext().getRealPath("\images\img01.jpg");
        // 获取下载的文件名
        String fileName = realPath.substring(realPath.lastIndexOf("\") + 1);
        System.out.println(fileName);
        // 让浏览器能支持我们下载我们需要的东西
//        resp.setHeader("Content-Disposition", "attchment;filename=" + fileName);
        // 当文件名为中文时， 会输出不成功， 将使用以下方法解决
        resp.setHeader("Content-Disposition", "attchment;filename=" + URLEncoder.encode(fileName, "UTF-8"));
        // 获取下载文件的输入流
        FileInputStream  fileInputStream = new FileInputStream(realPath);
        // 创建缓冲区
        int len = 0;
        byte[] buffer = new byte[1024];
        // 获取outputStream对象
        ServletOutputStream servletOutputStream = resp.getOutputStream();
        while((len = fileInputStream.read(buffer)) > 0){
            servletOutputStream.write(buffer, 0, len);
        }
        servletOutputStream.close();
        fileInputStream.close();
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}