java文件下载（生成多个二维码文件，下载zip文件）

Myth丶恋晨 2022-05-24 12:08 256阅读 0赞

最近公司有个需求，需要点击一个按钮生成二维码，然后把二维码打包成zip文件，然后下载zip文件，于是我做了个demo，这里分享一下。  
文件下载不能异步请求，因为我需要url后面动态拼接参数，所以这里用了button,具体前台代码如下可以实现下载（看压缩文件下载就可以了）：

<body>
    <input type="button" name="按钮啊" id="zipButton" value="压缩文件下载">
    <input type="button" name="按钮" id="button" value="按钮">
    <a href="/downLoadServlet">下载</a>
    <script src="js/jquery-3.3.1.min.js"></script>
    <script> $("#button").click(function () { window.location.href = "/downLoadServlet?templateId=111111"; }); $("#zipButton").click(function () { window.location.href = "/zipDownLoadServlet"; }) </script>
    </body>

后台主要分为这几个步骤：1生成二维码，2生成zip文件，3zip文件输出到输出流，4删除生成的文件。具体代码如下：

package com.mr.smart;
    
    import com.google.zxing.WriterException;
    
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.*;
    import java.net.URLEncoder;
    import java.util.Arrays;
    import java.util.List;
    
    @WebServlet(name = "ZipDownLoadServlet", value = "/zipDownLoadServlet")
    public class ZipDownLoadServlet extends HttpServlet { 
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
        }
    
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            String realPath = request.getSession().getServletContext().getRealPath("/");
            //1 生成二维码
            String projectName = "农银公杂费";
            String path = realPath + projectName;
            File file = new File(path);
            if (!file.exists()) {
                file.mkdirs();
            }
    
            List<String> list = Arrays.asList("code11.jpg", "code22.jpg", "code33.jpg");//已经存好的图片
            try {
                for (String x : list) {
                    String source = "G://" + x;
                    String qrCode = path + "/公杂费_" + x;
                    String url = "https://www.baidu.com/?name=" + x;
                    QRCodeUtil.generateQRImage(url, qrCode, source);//生成二维码的方法
                }
            } catch (WriterException e) {
                e.printStackTrace();
            }
            //2 生成zip文件
            ZipHelper.zipCompress(path, path + ".zip");
            //3 下载
            String zipFileName = path + ".zip";
            String filename = projectName + ".zip";
            //设置文件MIME类型
            response.setContentType(getServletContext().getMimeType(filename));
    
            response.setCharacterEncoding("UTF-8");
            //设置Content-Disposition
            response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(filename, "utf-8"));
            InputStream in = new FileInputStream(zipFileName);
            OutputStream out = response.getOutputStream();
            //写文件
            int b;
            while ((b = in.read()) != -1) {
                out.write(b);
            }
            out.flush();
            //4 删除多余文件
            deleteDir(new File(path));
            in.close();//先关闭输入流才能删除
            deleteDir(new File(zipFileName));
            out.close();
    
        }
    
        private boolean deleteDir(File dir) {
            if (dir.isDirectory()) {
                String[] children = dir.list();
                for (String s : children) {
                    boolean success = deleteDir(new File(dir, s));
                    if (!success) {
                        return false;
                    }
                }
            }
            // 目录此时为空，可以删除
            return dir.delete();
        }
    }

中间用到了生成二维码的工具类，生成zip文件的工具类，具体代码见:[https://github.com/zhanxupeng/DownLoadTest/][https_github.com_zhanxupeng_DownLoadTest]

[https_github.com_zhanxupeng_DownLoadTest]: https://github.com/zhanxupeng/DownLoadTest/