Java通过二维码下载Apk====安卓手机

1，创建springboot项目(新建maven项目)

2.创建包和类

3.源码

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import sun.misc.base64Encoder;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.URLEncoder;
import java.nio.channels.Channels;
import java.nio.channels.FileChannel;
import java.nio.channels.WritableByteChannel;

@Controller
@RequestMapping(value = "/downwanz")
public class DownApk {
    @RequestMapping(value = "/appwanzas")
    public static void DownLoadApp(HttpServletRequest request, HttpServletResponse response) throws UnsupportedEncodingException {

        //apk文件的路径  C:UsersAdministratorDesktopapp20210923
        String apkPath = "C:\webUpload\apk\20210923";
        String apkName = "xxxxxappName.apk";
        //为了单独解决，安卓手机火狐浏览器下载不显示中文或者乱码========无语！！！！！！！ 
        String fileName = "xxxxxappName";
        // 获得请求头中的User-Agent
        String agent = request.getHeader("User-Agent");
        // 根据不同的客户端进行不同的编码
        String filenameEncoder = "";
        if (agent.contains("MSIE")) {
            // IE浏览器
            filenameEncoder = URLEncoder.encode(apkName, "utf-8");
            filenameEncoder = filenameEncoder.replace("+", " ");
            //为了单独解决火狐浏览器下载不显示中文或者乱码
            response.setHeader("Content-Disposition", "attachment;filename=" + filenameEncoder);
        } else if (agent.contains("Firefox")) {
            // 火狐浏览器 编码
            base64Encoder base64Encoder = new base64Encoder();
            //base64 解码
            //base64Decoder decoder = new base64Decoder();
            filenameEncoder = "=?utf-8?B?" + base64Encoder.encode(apkName.getBytes("utf-8")) + "?=";
            //为了单独安卓手机解决火狐浏览器下载不显示中文或者乱码========无语！！！！！！！
            fileName = new String(fileName.getBytes("utf-8"), "iso8859-1");
            response.setHeader("Content-Disposition", "attachment;filename=" + fileName + ".apk");
        } else {
            // 其它浏览器
            filenameEncoder = URLEncoder.encode(apkName, "utf-8");
            //为了单独解决火狐浏览器下载不显示中文或者乱码
            response.setHeader("Content-Disposition", "attachment;filename=" + filenameEncoder);
        }
        //apk文件的绝对路径
        String apkPathfile =apkPath + "\" + apkName;
        //new 一个apk的文件对象
        File file = new File(apkPathfile);
        try {
            if(file.exists()){
                downloadFile(file,response);
            }
        }catch(Exception e) {
            System.out.println("下载文件错误"+e.getMessage());
        }
    }
    private static void downloadFile(File file, HttpServletResponse response ){
        OutputStream os = null;
        try {
            // 取得输出流
            os = response.getOutputStream();
            //String contentType = Files.probeContentType(Paths.get(file.getAbsolutePath()));
            //当前只下载apk格式文件 contentType
            response.setHeader("Content-Type", "application/octet-stream");
            response.addHeader("Content-Length", "" + file.length());
            FileInputStream fileInputStream = new FileInputStream(file);
            WritableByteChannel writableByteChannel = Channels.newChannel(os);
            FileChannel fileChannel = fileInputStream.getChannel();
            fileChannel.transferTo(0,fileChannel.size(),writableByteChannel);
            fileChannel.close();
            os.flush();
            writableByteChannel.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        //文件的关闭放在finally中
        finally {
            try {
                if (os != null) {
                    os.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

4, 将 ip + （端口）=======> localhost:8079/downwanz/appwanzas/ 直接访问下载apk文件
在线生成二维码地址：草料二维码