java浏览器文件下载实例（附源码下载地址）

   最近开始学习java，尝试实现浏览器文件下载，使用IDEA15构建了Springboot maven工程。根据网上的资料做了比较多的尝试，也遇到了许多问题，在此记录总结一下。由于是本地局域网的测试，所以代码中的文件的源目录都是直接写死的本地目录。

方式一：

 @RequestMapping("mydownload")    public ResponseEntity<Object> download(HttpServletResponse response) throws IOException {        String path = "D:\\111.ts";        File file = new File(path);        long size = file.length();        //为了解决中文名称乱码问题 这里是设置文件下载后的名称        String fileName = new String("000.ts".getBytes("UTF-8"), "iso-8859-1");        response.reset();        response.setHeader("Accept-Ranges", "bytes");        //设置文件下载是以附件的形式下载        response.setHeader("Content-disposition", String.format("attachment; filename=\"%s\"", fileName));        response.addHeader("Content-Length", String.valueOf(size));        ServletOutputStream sos = response.getOutputStream();        FileInputStream in = new FileInputStream(file);        BufferedOutputStream outputStream = new BufferedOutputStream(sos);        byte[] b = new byte[1024];        int i = 0;        while ((i = in.read(b)) > 0) {            outputStream.write(b, 0, i);        }        outputStream.flush();        sos.close();        outputStream.close();        in.close();        return new ResponseEntity<Object>(HttpStatus.OK);    }

方式二：

    //文件下载相关代码  与上面的方法类似    @RequestMapping("/download")    public String downloadFile(HttpServletRequest request, HttpServletResponse response) {        String fileName = "111.mov";        if (fileName != null) {            //当前是从该工程的WEB-INF//File//下获取文件(该目录可以在下面一行代码配置)            String realPath = request.getServletContext().getRealPath(                    "WEB-INF/File/");            File file = new File(realPath, fileName);            if (file.exists()) {                // 设置强制下载不打开                response.setContentType("application/force-download");                // 设置文件名                response.addHeader("Content-Disposition",                        "attachment;fileName=" + fileName);                byte[] buffer = new byte[1024];                FileInputStream fis = null;                BufferedInputStream bis = null;                try {                    fis = new FileInputStream(file);                    bis = new BufferedInputStream(fis);                    OutputStream os = response.getOutputStream();                    int i = bis.read(buffer);                    while (i != -1) {                        os.write(buffer, 0, i);                        i = bis.read(buffer);                    }                    System.out.println("success");                } catch (Exception e) {                    e.printStackTrace();                } finally {                    if (bis != null) {                        try {                            bis.close();                        } catch (IOException e) {                            e.printStackTrace();                        }                    }                    if (fis != null) {                        try {                            fis.close();                        } catch (IOException e) {                            e.printStackTrace();                        }                    }                }            }        }        return null;    }

方式三（在方式一的基础上加了下载进度和下载速度的简单实现）:

@Component    @Scope("prototype")    @RequestMapping("/downloadFile")    public class DownloadActionc {        @RequestMapping("downloadFiletest")        public ResponseEntity<Object> download(HttpServletResponse response) throws IOException {            String path = "D:\\abc.ts";            File file = new File(path);            String fileName = new String("test.ts".getBytes("UTF-8"), "iso-8859-1");            long fileTotalsize = file.length();            System.out.println("fileTotalsize = " + fileTotalsize);            response.reset();            response.setHeader("Accept-Ranges", "bytes");            response.setHeader("Content-disposition", String.format("attachment; filename=\"%s\"", fileName));            response.addHeader("Content-Length", String.valueOf(fileTotalsize));            ServletOutputStream sos = response.getOutputStream();            FileInputStream in = new FileInputStream(file);            BufferedOutputStream outputStream = new BufferedOutputStream(sos);            byte[] b = new byte[1024 * 2];//每次传输2K            long filecomplateSize = 0L;            double rateSpeed = 0;//速度            long rateProcess = 0L;//进度            int readSize = 0;            int i = 0;            int nbytes = 0;            long startTime = System.nanoTime();            //这里是下载进度和速度的简单实现 没有使用单独的线程进行速度计算            while ((readSize = in.read(b)) > 0) {                if (i % 20 == 0) {                    startTime = System.nanoTime();                }                filecomplateSize = filecomplateSize + readSize;                outputStream.write(b, 0, readSize);                nbytes = readSize + nbytes;                if (i % 20 == 19) {                    rateProcess = filecomplateSize / fileTotalsize;                    //时间差  System.nanoTime()的返回值精确度是毫微秒                    double currentTime = (System.nanoTime() - startTime);                    //将速度转化成比较通用的MB/S                    rateSpeed = ((nbytes / currentTime) * 1000 * 1000 * 1000) / 1024 / 1024;                    String strrateSpeed = String.format("%.2f", rateSpeed);                    rateSpeed = Double.valueOf(strrateSpeed);                    System.out.println(rateSpeed);                    System.out.println(rateSpeed);                    nbytes = 0;                }                i++;            }            outputStream.flush();            outputStream.close();            sos.close();            in.close();            return new ResponseEntity<Object>(HttpStatus.OK);        }

     在做下载的测试学习中了解到，浏览器的下载的目标路径程序中是不能修改的，这是浏览器自己的安全机制，所以浏览器的文件下载是下载到浏览器中设置的默认的下载路径中。本人是Java开发的小白，若有问题请各位大神及时指正指教。

项目下载地址(仅作为参考或者测试)：http://download.csdn.net/detail/coding13/9801171