文件下载&多级文件生成ZIP压缩包

1.文件下载

1.网上文件下载，一抓一大把。分享下一下资源

package io.renren.archives.controller;


import cn.hutool.core.util.ObjectUtil;
import io.renren.archives.entity.ReUploadFile;
import io.renren.archives.service.ReUploadFileService;
import io.renren.common.utils.DownFile;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


/**
 * @program: campus
 * @description: 上传文件
 * @author: shenzy
 * @create: 2020-08-10 09:11
 **/
@Controller
@RequestMapping("/upload")
public class ReDownLoadController {
    /**
     *  存放根目录
     */
    @Value("${rr.catalogs}")
    private String catalogs; // 磁盘盘符
    @Autowired
    private ReUploadFileService reUploadFileService;

    /**
     * 通过文件上传管理id下载文件
     * @param response
     * @param request
     * @param id
     * @return
     */
    @GetMapping("/downfileById")
    @ResponseBody
    public String  downfileById(HttpServletResponse response, HttpServletRequest request, @RequestParam(value = "id") Long id){
        ReUploadFile reUploadFile = reUploadFileService.getById(id);
        try{
            if (ObjectUtil.isNotNull(reUploadFile)){
                String filepath=catalogs+reUploadFile.getFileUrl();//D:/挂接文件/185fd11ae1314601822382bcef57626c-web前端开发工程师.pdf
                String suffix=reUploadFile.getFileUrl().substring(reUploadFile.getFileUrl().lastIndexOf("."));
                String fileName = reUploadFile.getFileName();
                DownFile.downFile(response,request,filepath,fileName+suffix);
            }
        }catch (Exception e){
            e.printStackTrace();
        }
        return null;
    }

}

package com.cloudwis.campus.util;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.URLEncoder;

/**
 * @program: campus
 * @description: 下载文件
 * @author: shenzy
 * @create: 2020-08-13 16:00
 **/
public class DownFile {
    public static void downFile(HttpServletResponse response, HttpServletRequest request, String path, String fileName) throws IOException {
        /** 将文件名称进行编码 */
        response.setContentType("content-type:octet-stream");
        if (DownFile.isMSBrowser(request)) {

            fileName = URLEncoder.encode(fileName, "UTF-8");
            response.setHeader("Content-disposition",
                    "attachment;filename=" +fileName);// 设置头部信息
        } else {

            fileName = new String(fileName.getBytes(), "ISO8859-1");
            response.setHeader("Content-disposition",
                    "attachment;filename=" +fileName);// 设置头部信息
        }
        File file = new File(path);
        if(!file.exists()){
            throw new FileNotFoundException("文件不存在");
        }
        /** 读取服务器端模板文件*/
        InputStream inputStream = new FileInputStream(file);

        /** 将流中内容写出去 .*/
        OutputStream outputStream = response.getOutputStream();
        byte[] buffer = new byte[1024];
        int len;
        while ((len = inputStream.read(buffer)) != -1) {
            outputStream.write(buffer, 0, len);
        }
        inputStream.close();
        outputStream.close();
    }
    //判断是否是ie浏览器，来处理下载文件名称乱码问题
    public static boolean isMSBrowser(HttpServletRequest request) {
        String[] IEBrowserSignals = {"MSIE", "Trident", "Edge"};
        String userAgent = request.getHeader("User-Agent");
        for (String signal : IEBrowserSignals) {
            if (userAgent.contains(signal)){
                return true;
            }
        }
        return false;
    }
}

2.多级文件生成压缩包

2.1 创建一个文件数组
2.2 maps是返回的多级路径
2.3 FileUtil.file(catalogs + fileUrl)封装， 放到数组里面
2.4 引用hutool依赖，压缩工具类很方便
2.5 生成的路径就在 根目录引用的路径在这里插入代码片

  File[] files  = new File[maps.size()];
        if (maps.size()>0){
            for (int i = 0; i < maps.size(); i++) {
                String fileUrl = maps.get(i).get("fileUrl").toString();
                files[i] = FileUtil.file(catalogs + fileUrl);
            }
        }
        String rchivesName= UUID.randomUUID() + reArchivesType.getArchivesName();
        ZipUtil.zip(FileUtil.file(catalogs  +rchivesName +".zip"), false, files);
        String url =  rchivesName+".zip";
        File files1  = new File(catalogs+url);
        String fileSize = getNetFileSizeDescription(files1.length());

这里是压缩包的大小自动转换，很方便

 /**
     * 压缩包大小转对应的大小
     * @param size
     * @return
     */
    public static String getNetFileSizeDescription(long size) {
        StringBuffer bytes = new StringBuffer();
        DecimalFormat format = new DecimalFormat("###.0");
        if (size >= 1024 * 1024 * 1024) {
            double i = (size / (1024.0 * 1024.0 * 1024.0));
            bytes.append(format.format(i)).append("GB");
        }
        else if (size >= 1024 * 1024) {
            double i = (size / (1024.0 * 1024.0));
            bytes.append(format.format(i)).append("MB");
        }
        else if (size >= 1024) {
            double i = (size / (1024.0));
            bytes.append(format.format(i)).append("KB");
        }
        else if (size < 1024) {
            if (size <= 0) {
                bytes.append("0B");
            }
            else {
                bytes.append((int) size).append("B");
            }
        }
        return bytes.toString();
    }