java实现通过浏览器方式下载文件及多个文件

怼烎@ 2022-04-15 00:29 826阅读 0赞

1、下载单个文件

public JsonView downPrintFile(){
    		//要下载的文件名 从前台传来
    		String fileNameNeedDown = request.getParameter("fileName");
                    //这里的路径是要下载的文件所在路径
    		String realPath = request.getServletContext().getRealPath("/")+"printController\\";
    		//要下载的文件路径+文件名
    		String aFilePath = realPath + fileNameNeedDown;
    		File file = null;
    		file = new File(aFilePath);
    		
    		BufferedInputStream bis = null;
    		BufferedOutputStream bos = null;
    		try {
    			String aFileName = null;
    			request.setCharacterEncoding("UTF-8");
    			String agent = request.getHeader("User-Agent").toUpperCase();
    			if ((agent.indexOf("MSIE") > 0)
    					|| ((agent.indexOf("RV") != -1) && (agent
    							.indexOf("FIREFOX") == -1)))
    				aFileName = URLEncoder.encode(fileNameNeedDown, "UTF-8");
    			else {
    				aFileName = new String(fileNameNeedDown.getBytes("UTF-8"), "ISO8859-1");
    			}
    			response.setContentType("application/octet-stream");//octet-stream为要下载文件是exe类型或看该文档http://www.w3school.com.cn/media/media_mimeref.asp
    			response.setHeader("Content-disposition", "attachment; filename="
    					+ aFileName);
    			response.setHeader("Content-Length", String.valueOf(file.length()));
    			bis = new BufferedInputStream(new FileInputStream(new File(aFilePath)));
    			bos = new BufferedOutputStream(response.getOutputStream());
    			byte[] buff = new byte[2048];
    			int bytesRead;
    			while (-1 != (bytesRead = bis.read(buff, 0, buff.length)))
    				bos.write(buff, 0, bytesRead);
    			System.out.println("success");
    			bos.flush();
    		} catch (Exception e) {
    			System.out.println("失败！");
    		} finally {
    			try {
    				if (bis != null) {
    					bis.close();
    				}
    				if (bos != null) {
    					bos.close();
    				}
    //				file.delete();
    			} catch (Exception e) {
    			}
    		}
    		return new JsonView();
    	}

2、下载多个文件，原理是依次下载每个文件，下载完一个加入压缩包，再将压缩包下载下来。最终下载下来的文件是个压缩包。

//下载打印的exe文件至本地
        public void downPrintLodopFile() throws Exception{
    //    	String property = System.getProperty("os.arch");//amd64
        	//获得exe文件路径
        	String realPath = request.getServletContext().getRealPath("/")+File.separator+"printFiles\\";
        	String setup_fileName = "Setup.exe";
        	String install32_fileName = "install32.exe";
        	String install64_fileName = "install64.exe";
        	//执行down
        	down(realPath, new String[]{realPath+setup_fileName , realPath+install32_fileName , realPath+install64_fileName }, request, response);
    		
    	}

public void down(String path, String[] files, HttpServletRequest request, HttpServletResponse response) throws Exception {
    		// path 压缩文件初始设置 
    		String base_name = "printFiles";
    		String fileZip = base_name + ".zip"; // 拼接zip文件,之后下载下来的压缩文件的名字
    		String filePath = path + fileZip;// 之后用来生成zip文件
    
    		// 创建临时压缩文件
    		try {
    			BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(filePath));
    			ZipOutputStream zos = new ZipOutputStream(bos);
    			ZipEntry ze = null;
    			for (int i = 0; i < files.length; i++) {// 将所有需要下载的文件都写入临时zip文件
    				BufferedInputStream bis = new BufferedInputStream(
    						new FileInputStream(files[i]));
    				ze = new ZipEntry(
    						files[i].substring(files[i].lastIndexOf("\\")));
    				zos.putNextEntry(ze);
    				int s = -1;
    				while ((s = bis.read()) != -1) {
    					zos.write(s);
    				}
    				bis.close();
    			}
    			zos.flush();
    			zos.close();
    		} catch (IOException e) {
    			e.printStackTrace();
    		}
    		// 以上，临时压缩文件创建完成
    
    		// 进行浏览器下载
    		// 获得浏览器代理信息
    		String agent = request.getHeader("User-Agent").toUpperCase();
    		// 判断浏览器代理并分别设置响应给浏览器的编码格式
    		String finalFileName = null;
    		if ((agent.indexOf("MSIE") > 0)
    				|| ((agent.indexOf("RV") != -1) && (agent.indexOf("FIREFOX") == -1)))
    			finalFileName = URLEncoder.encode(fileZip, "UTF-8");
    		else {
    			finalFileName = new String(fileZip.getBytes("UTF-8"), "ISO8859-1");
    		}
    		response.setContentType("application/x-download");// 告知浏览器下载文件，而不是直接打开，浏览器默认为打开
    		response.setHeader("Content-Disposition", "attachment;filename=\""
    				+ finalFileName + "\"");// 下载文件的名称
    		//输出到本地
    		ServletOutputStream servletOutputStream = response.getOutputStream();
    		DataOutputStream temps = new DataOutputStream(servletOutputStream);
    
    		DataInputStream in = new DataInputStream(new FileInputStream(filePath));// 浏览器下载临时文件的路径
    		byte[] b = new byte[2048];
    		File reportZip = new File(filePath);// 之后用来删除临时压缩文件
    		try {
    			while ((in.read(b)) != -1) {
    				temps.write(b);
    			}
    			temps.flush();
    		} catch (Exception e) {
    			e.printStackTrace();
    		} finally {
    			if (temps != null)
    				temps.close();
    			if (in != null)
    				in.close();
    			if (reportZip != null)
    				reportZip.delete();// 删除服务器本地产生的临时压缩文件
    			servletOutputStream.close();
    		}
    	}

这是参考网上大家的代码，最后项目写完自己写个记录，参考链接也找不到了，如有侵权请联系本人。