目录

• 1、前置条件
• 2、单一文件下载
• • 2.1、本地文件下载
  • 2.2、网络文件下载
• 3、zip压缩包批量下载
• • 3.1、本地文件批量下载
  • 3.2、网络文件批量下载
• 4、说三遍

1、前置条件

demo中，将多个文件通过zip的形式进行下载，所以需要引入以下maven坐标：

 <dependency>     <groupId>org.apache.commons</groupId>     <artifactId>commons-compress</artifactId>     <version>1.20</version> </dependency>

为了更好的代码可读性，将针对本地、网络文件下载、zip压缩包批量下载封装一个工具类，代码如下：
下载实现的核心就是下面的工具类代码，可以在任意的项目中进行使用；

import org.apache.commons.compress.archivers.ArchiveEntry;import org.apache.commons.compress.archivers.zip.Zip64Mode;import org.apache.commons.compress.archivers.zip.ZipArchiveEntry;import org.apache.commons.compress.archivers.zip.ZipArchiveOutputStream;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import javax.activation.MimetypesFileTypeMap;import javax.servlet.ServletOutputStream;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.*;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.URL;import java.net.URLEncoder;import java.text.SimpleDateFormat;import java.util.Date;import java.util.List;import java.util.Map;/** * @Author: LiHuaZhi * @Date: 2022/1/19 13:54 * @Description: **/public class FileUtil {    private static final Logger logger = LoggerFactory.getLogger(FileUtil.class);    private static MimetypesFileTypeMap mimetypesFileTypeMap;    /**     * 下载http文件流     *     * @param urlStr     * @param request     * @param response     * @param fileName     * @return     */    public static void downloadHttpFile(String urlStr, HttpServletRequest request, HttpServletResponse response, String fileName) { ServletOutputStream out = null; InputStream inputStream = null; try {     URL url = new URL(urlStr);     HttpURLConnection conn = (HttpURLConnection) url.openConnection();     //得到输入流     inputStream = conn.getInputStream();     //获取自己数组     byte[] getData = FileUtil.inputStreamToByte(inputStream);     // 下载     out = response.getOutputStream();     long contentLength = getData.length;     FileUtil.setResponse(fileName, contentLength, request, response);     out.write(getData);     out.flush(); } catch (Exception e) {     throw new RuntimeException("下载失败!"); } finally {     try {  if (out != null) {      out.close();  }  if (inputStream != null) {      inputStream.close();  }     } catch (IOException e) {  e.printStackTrace();     } }    }    //File、FileInputStream 转换为byte数组    public static byte[] inputStreamToByte(InputStream inputStream) { try {     byte[] buffer = new byte[1024];     int len = 0;     ByteArrayOutputStream bos = new ByteArrayOutputStream();     while ((len = inputStream.read(buffer)) != -1) {  bos.write(buffer, 0, len);     }     bos.close();     return bos.toByteArray(); } catch (Exception e) {     throw new RuntimeException("文件转换失败!"); }    }    /**     * 下载文件流     *     * @param file     * @param request     * @param response     * @param fileName     * @return     */    public static void downloadFile(File file, HttpServletRequest request, HttpServletResponse response, String fileName) { if (file != null && file.exists() && file.length() > 0L) {     try {  RandomAccessFile randomFile = new RandomAccessFile(file, "r");  Throwable var5 = null;  Object var54;  try {      ServletOutputStream out = response.getOutputStream();      Throwable var7 = null;      try {   long contentLength = randomFile.length();   String range = request.getHeader("Range");   long start = 0L;   long end = 0L;   if (range != null && range.startsWith("bytes=")) {String[] values = range.split("=")[1].split("-");start = Long.parseLong(values[0]);if (values.length > 1) {    end = Long.parseLong(values[1]);}   }   int requestSize;   if (end != 0L && end > start) {requestSize = Long.valueOf(end - start + 1L).intValue();   } else {requestSize = 2147483647;   }   FileUtil.setResponse(fileName, contentLength, request, response);   randomFile.seek(start);   byte[] buffer;   for (int needSize = requestSize; needSize > 0; needSize -= buffer.length) {buffer = new byte[1024];int len = randomFile.read(buffer);if (needSize < buffer.length) {    out.write(buffer, 0, needSize);} else {    out.write(buffer, 0, len);    if (len < buffer.length) { break;    }}   }   out.flush();   var54 = null;      } catch (Throwable var47) {   var7 = var47;   throw var47;      } finally {   if (out != null) {if (var7 != null) {    try { out.close();    } catch (Throwable var46) { var7.addSuppressed(var46);    }} else {    out.close();}   }      }  } catch (Throwable var49) {      var5 = var49;      throw var49;  } finally {      if (randomFile != null) {   if (var5 != null) {try {    randomFile.close();} catch (Throwable var45) {    var5.addSuppressed(var45);}   } else {randomFile.close();   }      }  }     } catch (IOException var51) {  logger.debug(var51.getMessage(), var51);  throw new RuntimeException(var51.getMessage());     } } else {     throw new RuntimeException("文件为空或不存在！"); }    }    /**     * @param fileName     * @param contentLength     * @param request     * @param response     * @return     */    public static void setResponse(String fileName, long contentLength, HttpServletRequest request, HttpServletResponse response) { try {     response.setContentType(FileUtil.getContentType("0.jpg"));     boolean isPreview = "preview".equalsIgnoreCase(request.getParameter("source"));     response.addHeader("Content-Disposition", (!isPreview ? "attachment; " : "") + "filename*=utf-8'zh_cn'" + URLEncoder.encode(fileName, "UTF-8"));     response.setHeader("Accept-Ranges", "bytes");     String range = request.getHeader("Range");     if (range == null) {  response.setHeader("Content-Length", String.valueOf(contentLength));     } else {  response.setStatus(206);  long requestStart = 0L;  long requestEnd = 0L;  String[] ranges = range.split("=");  if (ranges.length > 1) {      String[] rangeDatas = ranges[1].split("-");      requestStart = Long.parseLong(rangeDatas[0]);      if (rangeDatas.length > 1) {   requestEnd = Long.parseLong(rangeDatas[1]);      }  }  long length = 0L;  if (requestEnd > 0L) {      length = requestEnd - requestStart + 1L;      response.setHeader("Content-Length", String.valueOf(length));      response.setHeader("Content-Range", "bytes " + requestStart + "-" + requestEnd + "/" + contentLength);  } else {      length = contentLength - requestStart;      response.setHeader("Content-Length", String.valueOf(length));      response.setHeader("Content-Range", "bytes " + requestStart + "-" + (contentLength - 1L) + "/" + contentLength);  }     } } catch (Exception e) {     throw new RuntimeException("response响应失败!"); }    }    public static String getContentType(String fileName) { if (mimetypesFileTypeMap == null) {     mimetypesFileTypeMap = new MimetypesFileTypeMap(); } return mimetypesFileTypeMap.getContentType(fileName);    }    /**     * 将磁盘的多个文件打包成压缩包并输出流下载     *     * @param pathList     * @param request     * @param response     */    public static void zipDirFileToFile(List<Map<String, String>> pathList, HttpServletRequest request, HttpServletResponse response) { try {     // 设置response参数并且获取ServletOutputStream     ZipArchiveOutputStream zous = getServletOutputStream(response);     for (Map<String, String> map : pathList) {  String fileName = map.get("name");  File file = new File(map.get("path"));  InputStream inputStream = new FileInputStream(file);  setByteArrayOutputStream(fileName, inputStream, zous);     }     zous.close(); } catch (Exception e) {     e.printStackTrace(); }    }    /**     * 将网络url资源文件的多个文件打包成压缩包并输出流下载     *     * @param pathList     * @param request     * @param response     */    public static void zipUrlToFile(List<Map<String, String>> pathList, HttpServletRequest request, HttpServletResponse response) { try {     // 设置response参数并且获取ServletOutputStream     ZipArchiveOutputStream zous = getServletOutputStream(response);     for (Map<String, String> map : pathList) {  String fileName = map.get("name");  InputStream inputStream = getInputStreamFromUrl(map.get("path"));  setByteArrayOutputStream(fileName, inputStream, zous);     }     zous.close(); } catch (Exception e) {     e.printStackTrace(); }    }    private static ZipArchiveOutputStream getServletOutputStream(HttpServletResponse response) throws Exception { String outputFileName = "文件" + new SimpleDateFormat("yyyyMMddHHmmss").format(new Date()) + ".zip"; response.reset(); response.setHeader("Content-Type", "application/octet-stream"); response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(outputFileName, "UTF-8")); response.setHeader("Pragma", "no-cache"); response.setHeader("Cache-Control", "no-cache"); ServletOutputStream out = response.getOutputStream(); ZipArchiveOutputStream zous = new ZipArchiveOutputStream(out); zous.setUseZip64(Zip64Mode.AsNeeded); return zous;    }    private static void setByteArrayOutputStream(String fileName, InputStream inputStream, ZipArchiveOutputStream zous) throws Exception { ByteArrayOutputStream baos = new ByteArrayOutputStream(); byte[] buffer = new byte[1024]; int len; while ((len = inputStream.read(buffer)) != -1) {     baos.write(buffer, 0, len); } baos.flush(); byte[] bytes = baos.toByteArray(); //设置文件名 ArchiveEntry entry = new ZipArchiveEntry(fileName); zous.putArchiveEntry(entry); zous.write(bytes); zous.closeArchiveEntry(); baos.close();    }    /**     * 通过网络地址获取文件InputStream     *     * @param path 地址     * @return     */    private static InputStream getInputStreamFromUrl(String path) { URL url = null; InputStream is = null; try {     url = new URL(path); } catch (MalformedURLException e) {     e.printStackTrace(); } try {     HttpURLConnection conn = (HttpURLConnection) url.openConnection();     conn.setDoInput(true);     conn.connect();     is = conn.getInputStream(); } catch (IOException e) {     e.printStackTrace(); } return is;    }}

2、单一文件下载

2.1、本地文件下载

Controller：

@RestController@RequestMapping("/test")public class TestController {    @Resource    private HttpServletResponse response;    @Resource    private HttpServletRequest request;    @GetMapping(value = "/down/file")    public void downloadFileStream() { // 文件本地位置 String filePath = "C:\\Users\\LiGezZ\\Desktop\\测试文件.txt"; // 文件名称 String fileName = "测试文件.txt"; File file = new File(filePath); FileUtil.downloadFile(file, request, response, fileName); // 浏览器访问：http://x.x.x.x/test/down/file    }}

2.2、网络文件下载

注意： 通过网络请求下载时，设置的fileName一定要与http资源的后缀一致；
Controller：

@RestController@RequestMapping("/test")public class TestController {    @Resource    private HttpServletResponse response;    @Resource    private HttpServletRequest request;    @GetMapping(value = "/down/file/http")    public void downloadFileHttpStream() { // 文件网络地址 String urlStr = "https://code.jquery.com/jquery-3.6.0.js"; // 文件名称 String fileName = "测试文件.js"; FileUtil.downloadHttpFile(urlStr, request, response, fileName); // 浏览器访问：http://x.x.x.x/test/down/file/http    }}

3、zip压缩包批量下载

3.1、本地文件批量下载

@RestController@RequestMapping("/test")public class TestController {    @Resource    private HttpServletResponse response;    @Resource    private HttpServletRequest request;    @GetMapping(value = "/down/zip")    public void downloadZipStream() { List<Map<String, String>> mapList = new ArrayList<>(); String basePath = "C:\\Users\\LiGezZ\\Desktop\\测试文件_"; // 模拟下载本地的5个文件，分别为测试文件1~5 for (int i = 1; i <= 5; i++) {     Map<String, String> map = new HashMap<>();     map.put("path", basePath + i + ".txt");     map.put("name", "测试文件_" + i + ".txt");     mapList.add(map); } FileUtil.zipDirFileToFile(mapList, request, response); // 浏览器访问：http://x.x.x.x/test/down/zip    }}

效果：

3.2、网络文件批量下载

注意： 通过网络请求下载时，设置的fileName一定要与http资源的后缀一致；

@RestController@RequestMapping("/test")public class TestController {    @Resource    private HttpServletResponse response;    @Resource    private HttpServletRequest request;    @GetMapping(value = "/down/zip/http")    public void downloadZipHttpByDataStream() { List<Map<String, String>> mapList = new ArrayList<>(); String urlStr = "https://code.jquery.com/jquery-3.6.0.js"; // 模拟下载本地的5个文件，分别为测试文件1~5 for (int i = 1; i <= 5; i++) {     Map<String, String> map = new HashMap<>();     map.put("path", urlStr);     map.put("name", "测试文件_" + i + ".js");     mapList.add(map); } FileUtil.zipUrlToFile(mapList, request, response); // 浏览器访问：http://x.x.x.x/test/down/zip/http    }}

效果：

4、说三遍

下载实现的核心就是工具类代码，可以在任意的项目中进行使用；！
下载实现的核心就是工具类代码，可以在任意的项目中进行使用；！
下载实现的核心就是工具类代码，可以在任意的项目中进行使用；！

使用zip批量功能一定要配置开头提供的maven坐标
使用zip批量功能一定要配置开头提供的maven坐标
使用zip批量功能一定要配置开头提供的maven坐标