//设置响应内容类型为PDF类型

        response.setContentType("application/pdf");  

        ServletOutputStream sos = response.getOutputStream();  

        //不在网页中打开，而是直接下载该文件，下载后的文件名为“Example.pdf”

        //response.setHeader("Content-disposition", "attachment;filename=Example.pdf");  

        File pdf = null;

        FileInputStream fis = null;

        byte[] buffer = new byte[1024*1024];

        pdf = new File("D:\\test.pdf");

        response.setContentLength((int) pdf.length());

        fis = new FileInputStream(pdf);

        int readBytes = -1;

        while((readBytes = fis.read(buffer, 0, 1024*1024)) != -1){

            sos.write(buffer, 0, 1024*1024);

        }

        sos.close();

        fis.close();