java --文件下载

配置部分，请参考 java--文件上传

1.controller层代码

    /**
     * 测试文件下载
     * 
     * **/
    @RequestMapping(value = "/download/{fileName}", method = RequestMethod.GET)
    public ResultObject download(@PathVariable("fileName") String fileName,
                                HttpServletRequest request, 
                                HttpServletResponse response) {
        
        System.out.println("fileName:" + fileName);
        ResultObject ro = customerCommentService.down(fileName,request,response);
        return ro;
    }

2.service层代码

    /**
     * 测试文件下载
     * 
     * **/
    public ResultObject down(String fileName,
                            HttpServletRequest request, 
                            HttpServletResponse response);

3.实现层代码

    /**
     * 测试文件下载
     * 
     * **/
    public ResultObject down(String fileName,
                            HttpServletRequest request, 
                            HttpServletResponse response){
    
        ResultObject ro = new ResultObject();
        
        //设置响应内容类型
        response.setContentType("text/html;charset=utf-8");
        //以下也是一种响应类型
        //response.setContentType("multipart/form-data");
        //设置字符编码
        try {
            request.setCharacterEncoding("UTF-8");
        } catch (UnsupportedEncodingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        //输入流
        java.io.BufferedInputStream bis = null;
        //输出流
        java.io.BufferedOutputStream bos = null;
        
        //得到下载文件路径
        String ctxPath=request.getSession().getServletContext().getRealPath("/")+"Upload\\";

        //测试文件
        //fileName = "cc.txt";
        //下载路径
        String downLoadPath = ctxPath + fileName;
        System.out.println("下载文件路径:"+downLoadPath);
        
        try{
            //获取文件长度
            long fileLength = new File(downLoadPath).length();
            //设置文件输出类型
            response.setContentType("application/x-msdownload;");
            response.setHeader("Content-disposition", "attachment; filename="  
                    + new String(fileName.getBytes("utf-8"), "ISO8859-1"));
            response.setHeader("Content-Length", String.valueOf(fileLength));
            
            //从地址得到文件输入流
            //这个FileInputStream后面是否是应该写成FileInputStream(new File(downLoadPath))
            bis = new BufferedInputStream(new FileInputStream(downLoadPath));
            //响应输入流，输出
            bos = new BufferedOutputStream(response.getOutputStream());
            byte[] buff = new byte[2048]; 
            int bytesRead;
            //从输入流读入到buff，从buff写入输出流
            while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) {   
                bos.write(buff, 0, bytesRead);   
            }  
            
            //下载成功
        }catch(Exception e)
        {
            e.printStackTrace();
            //下载失败
        }finally
        {
            if (bis != null)
            {
                try {
                    bis.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            if (bos != null)
            {
                try {
                    bos.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
        
        return ro;
    }

4.在火狐浏览器输入

192.168.2.67:8080/pets/download/cc

5.出现以下截图

自此，结束。