使用Java打包下载zip文件

本文提供打包下载目标url文件为zip解决方案

工具类

package com.solvay.utils.file;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.*;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

/**
 * @author syb
 * @date 2022/9/29
 */
public class UrlFilesToZip {
    private static final Logger logger = LoggerFactory.getLogger(UrlFilesToZip.class);

    public final static Map<String, String> FILE_TYPE_MAP = new HashMap<String, String>();

    //通过url下载zip
    public static void filesdown(HttpServletResponse response, List<String> urls,String name){
        try {
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            ZipOutputStream zos = new ZipOutputStream(bos);
            int idx = 1;
            for (String oneFile : urls) {
                byte[] bytes = getFileFromURL(oneFile);
                //可以自动检测byte[]中文件格式，就是有点慢，如果要求速度就顶死
                //String fileTypeByStream = getFileTypeByStream(bytes);
                zos.putNextEntry(new ZipEntry(name + idx+".doc"));
                zos.write(bytes, 0, bytes.length);
                zos.closeEntry();
                idx++;
            }
            zos.close();
            OutputStream os = response.getOutputStream();
            os.write(bos.toByteArray());
            os.close();
        } catch (FileNotFoundException ex) {
            logger.error("FileNotFoundException", ex);
        } catch (Exception ex) {
            logger.error("Exception", ex);
        }
    }


    //根据文件链接把文件下载下来并且转成字节码
    public static byte[] getFileFromURL(String urlPath) {
        byte[] data = null;
        InputStream is = null;
        HttpURLConnection conn = null;
        try {
            URL url = new URL(urlPath);
            conn = (HttpURLConnection) url.openConnection();
            conn.setDoInput(true);
            // conn.setDoOutput(true);
//            conn.setRequestMethod("GET");
            conn.setConnectTimeout(6000);
            is = conn.getInputStream();
            if (conn.getResponseCode() == 200) {
                data = readInputStream(is);
            } else {
                data = null;
            }
        } catch (MalformedURLException e) {
            logger.error("MalformedURLException", e);
        } catch (IOException e) {
            logger.error("IOException", e);
        } finally {
            try {
                if (is != null) {
                    is.close();
                }
            } catch (IOException e) {
                logger.error("IOException", e);
            }
            conn.disconnect();
        }
        return data;
    }


    private static byte[] readInputStream(InputStream is) {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        byte[] buffer = new byte[1024];
        int length = -1;
        try {
            while ((length = is.read(buffer)) != -1) {
                baos.write(buffer, 0, length);
            }
            baos.flush();
        } catch (IOException e) {
            logger.error("IOException", e);
        }
        byte[] data = baos.toByteArray();
        try {
            is.close();
            baos.close();
        } catch (IOException e) {
            logger.error("IOException", e);
        }
        return data;
    }

    private static void getAllFileType()
    {
        FILE_TYPE_MAP.put("jpg", "FFD8FF"); //JPEG (jpg)
        FILE_TYPE_MAP.put("png", "89504E47");  //PNG (png)
        FILE_TYPE_MAP.put("gif", "47494638");  //GIF (gif)
        FILE_TYPE_MAP.put("tif", "49492A00");  //TIFF (tif)
        FILE_TYPE_MAP.put("bmp", "424D"); //Windows Bitmap (bmp)
        FILE_TYPE_MAP.put("dwg", "41433130"); //CAD (dwg)
        FILE_TYPE_MAP.put("html", "68746D6C3E");  //HTML (html)
        FILE_TYPE_MAP.put("rtf", "7B5C727466");  //Rich Text Format (rtf)
        FILE_TYPE_MAP.put("xml", "3C3F786D6C");
        FILE_TYPE_MAP.put("zip", "504B0304");
        FILE_TYPE_MAP.put("rar", "52617221");
        FILE_TYPE_MAP.put("psd", "38425053");  //Photoshop (psd)
        FILE_TYPE_MAP.put("eml", "44656C69766572792D646174653A");  //Email [thorough only] (eml)
        FILE_TYPE_MAP.put("dbx", "CFAD12FEC5FD746F");  //Outlook Express (dbx)
        FILE_TYPE_MAP.put("pst", "2142444E");  //Outlook (pst)
        FILE_TYPE_MAP.put("xls", "D0CF11E0");  //MS Word
        FILE_TYPE_MAP.put("docx","504B0304"); //doxc
        FILE_TYPE_MAP.put("doc", "D0CF11E0");  //MS Excel 注意：word 和 excel的文件头一样
        FILE_TYPE_MAP.put("mdb", "5374616E64617264204A");  //MS Access (mdb)
        FILE_TYPE_MAP.put("wpd", "FF575043"); //WordPerfect (wpd)
        FILE_TYPE_MAP.put("eps", "252150532D41646F6265");
        FILE_TYPE_MAP.put("ps", "252150532D41646F6265");
        FILE_TYPE_MAP.put("pdf", "255044462D312E");  //Adobe Acrobat (pdf)
        FILE_TYPE_MAP.put("qdf", "AC9EBD8F");  //Quicken (qdf)
        FILE_TYPE_MAP.put("pwl", "E3828596");  //Windows Password (pwl)
        FILE_TYPE_MAP.put("wav", "57415645");  //Wave (wav)
        FILE_TYPE_MAP.put("avi", "41564920");
        FILE_TYPE_MAP.put("ram", "2E7261FD");  //Real Audio (ram)
        FILE_TYPE_MAP.put("rm", "2E524D46");  //Real Media (rm)
        FILE_TYPE_MAP.put("mpg", "000001BA");  //
        FILE_TYPE_MAP.put("mov", "6D6F6F76");  //Quicktime (mov)
        FILE_TYPE_MAP.put("asf", "3026B2758E66CF11"); //Windows Media (asf)
        FILE_TYPE_MAP.put("mid", "4D546864");  //MIDI (mid)
    }


    public final static String getFileTypeByStream(byte[] b)
    {
        String filetypeHex = String.valueOf(getFileHexString(b));
        Iterator<Map.Entry<String, String>> entryiterator = FILE_TYPE_MAP.entrySet().iterator();
        while (entryiterator.hasNext()) {
            Map.Entry<String,String> entry =  entryiterator.next();
            String fileTypeHexValue = entry.getValue();
            if (filetypeHex.toUpperCase().startsWith(fileTypeHexValue)) {
                return entry.getKey();
            }
        }
        return null;
    }


    public final static String getFileHexString(byte[] b)
    {
        StringBuilder stringBuilder = new StringBuilder();
        if (b == null || b.length <= 0)
        {
            return null;
        }
        for (int i = 0; i < b.length; i++)
        {
            int v = b[i] & 0xFF;
            String hv = Integer.toHexString(v);
            if (hv.length() < 2)
            {
                stringBuilder.append(0);
            }
            stringBuilder.append(hv);
        }
        return stringBuilder.toString();
    }
}

使用案例

    @GetMapping("/testDownloadZip")
    public void testDownloadZip(HttpServletResponse response){
        try {
            List<String> urls=new ArrayList<>();
            String url="http://ip:port/statics/2022/09/29/xxx_20220929102720A024.doc";
            urls.add(url);
            UrlFilesToZip.filesdown(response,urls,"测试导出zip");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }