后台代码，仅需读取文件并变成二进制流：
/**
* bolb 测试
*/

public void getFile(HttpServletResponse response, HttpServletRequest request){
    File f = new File("service-web/src/main/resources/static/images/video1.mp4");

    String fileName = f.getName();
    String agent = request.getHeader("User-Agent").toUpperCase();

    InputStream fis = null;

    OutputStream os = null;
    try{

        fis = new BufferedInputStream(new FileInputStream(f.getPath()));

        byte[] buffer;

        buffer = new byte[fis.available()];

        fis.read(buffer);

        response.reset();

        //由于火狐和其他浏览器显示名称的方式不相同，需要进行不同的编码处理

        if(agent.indexOf("FIREFOX") != -1){//火狐浏览器

            response.addHeader("Content-Disposition", "attachment;filename="+ new String(fileName.getBytes("GB2312"),"ISO-8859-1"));

        }else{//其他浏览器

            response.addHeader("Content-Disposition", "attachment;filename="+ URLEncoder.encode(fileName, "UTF-8"));

        }

        //设置response编码

        response.setCharacterEncoding("UTF-8");

        response.addHeader("Content-Length", ""+ f.length());

        //设置输出文件类型

        response.setContentType("video/mpeg4");

        //获取response输出流

        os = response.getOutputStream();

        // 输出文件

        os.write(buffer);

    }catch(Exception e){

        System.out.println(e.getMessage());

    } finally {

        //关闭流

        try {

            if (fis != null) {

                fis.close();

            }

        } catch (IOException e) {

            System.out.println(e.getMessage());

        } finally {

            try {

                if (os != null) {

                    os.flush();

                }

            } catch (IOException e) {

                System.out.println(e.getMessage());

            } finally {

                try {

                    if (os != null) {

                        os.close();

                    }

                } catch (IOException e) {

                    System.out.println(e.getMessage());

                }

            }
        }
    }
}

前台接收代码：

function demoBlob() {
	//创建XMLHttpRequest对象
    var xhr = new XMLHttpRequest();

    //配置请求方式、请求地址以及是否同步

    xhr.open('POST', '/getBolb', true);

    //设置请求结果类型为blob

    xhr.responseType = 'blob';

    //请求成功回调函数

    xhr.onload = function (e) {
        if (this.status == 200) {//请求成功

            //获取blob对象

            var blob = this.response;

            //获取blob对象地址，并把值赋给容器
            console.log("!_______________________________________________________________________________________________")
            console.log("加密后的视频路径："+URL.createObjectURL(blob));
            console.log("!_______________________________________________________________________________________________")

        }

    };

    xhr.send();
}