有时候在系统中需要一次性下载多个文件，但逐个下载文件比较麻烦。这时候，最好的解决办法是将所有文件打包成一个压缩文件，然后下载这个压缩文件，这样就可以一次性获取所有所需的文件了。
下面是一个名为CompressUtil的工具类的代码，它提供了一些方法来处理文件压缩和下载操作：
import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.lucene.util.RamUsageEstimator;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.util.*;
import java.util.zip.*;
/**
* @author fhey
* @date 2023-05-11 20:48:28
* @description: 压缩工具类
*/
public class CompressUtil {
private static final Logger logger = LoggerFactory.getLogger(CompressUtil.class);
/**
* 将文件打包到zip并创建文件
*
* @param sourceFilePath
* @param zipFilePath
* @throws IOException
*/
public static void createLocalCompressFile(String sourceFilePath, String zipFilePath) throws IOException {
createLocalCompressFile(sourceFilePath, zipFilePath, null);
}
/**
* 将文件打包到zip并创建文件
*
* @param sourceFilePath
* @param zipFilePath
* @param zipName
* @throws IOException
*/
public static void createLocalCompressFile(String sourceFilePath, String zipFilePath, String zipName) throws IOException {
File sourceFile = new File(sourceFilePath);
if (!sourceFile.exists()) {
throw new RuntimeException(sourceFilePath + "不存在！");
}
if(StringUtils.isBlank(zipName)){
zipName = sourceFile.getName();
}
File zipFile = createNewFile(zipFilePath + File.separator + zipName + ".zip");
try (FileOutputStream fileOutputStream = new FileOutputStream(zipFile)) {
compressFile(sourceFile, fileOutputStream);
}
}
/**
* 获取压缩文件流
*
* @param sourceFilePath
* @return ByteArrayOutputStream
* @throws IOException
*/
public static OutputStream compressFile(String sourceFilePath, OutputStream outputStream) throws IOException {
File sourceFile = new File(sourceFilePath);
if (!sourceFile.exists()) {
throw new RuntimeException(sourceFilePath + "不存在！");
}
return compressFile(sourceFile, outputStream);
}
/**
* 获取压缩文件流
*
* @param sourceFile
* @return ByteArrayOutputStream
* @throws IOException
*/
private static OutputStream compressFile(File sourceFile, OutputStream outputStream) throws IOException {
try (CheckedOutputStream checkedOutputStream = new CheckedOutputStream(outputStream, new CRC32());
ZipOutputStream zipOutputStream = new ZipOutputStream(checkedOutputStream)) {
doCompressFile(sourceFile, zipOutputStream, StringUtils.EMPTY);
return outputStream;
}
}
/**
* 处理目录下的文件
*
* @param sourceFile
* @param zipOutputStream
* @param zipFilePath
* @throws IOException
*/
private static void doCompressFile(File sourceFile, ZipOutputStream zipOutputStream, String zipFilePath) throws IOException {
// 如果文件是隐藏的，不进行压缩
if (sourceFile.isHidden()) {
return;
}
if (sourceFile.isDirectory()) {//如果是文件夹
handDirectory(sourceFile, zipOutputStream, zipFilePath);
} else {//如果是文件就添加到压缩包中
try (FileInputStream fileInputStream = new FileInputStream(sourceFile)) {
//String fileName = zipFilePath + File.separator + sourceFile.getName();
String fileName = zipFilePath + sourceFile.getName();
addCompressFile(fileInputStream, fileName, zipOutputStream);
//String fileName = zipFilePath.replace("\\", "/") + "/" + sourceFile.getName();
//addCompressFile(fileInputStream, fileName, zipOutputStream);
}
}
}
/**
* 处理文件夹
*
* @param dir 文件夹
* @param zipOut 压缩包输出流
* @param zipFilePath 压缩包中的文件夹路径
* @throws IOException
*/
private static void handDirectory(File dir, ZipOutputStream zipOut, String zipFilePath) throws IOException {
File[] files = dir.listFiles();
if (ArrayUtils.isEmpty(files)) {
ZipEntry zipEntry = new ZipEntry(zipFilePath + dir.getName() + File.separator);
zipOut.putNextEntry(zipEntry);
zipOut.closeEntry();
return;
}
for (File file : files) {
doCompressFile(file, zipOut, zipFilePath + dir.getName() + File.separator);
}
}
/**
* 获取压缩文件流
*
* @param documentList 需要压缩的文件集合
* @return ByteArrayOutputStream
*/
public static OutputStream compressFile(List<FileInfo> documentList, OutputStream outputStream) {
Map<String, List<FileInfo>> documentMap = new HashMap<>();
documentMap.put("", documentList);
return compressFile(documentMap, outputStream);
}
/**
* 将文件打包到zip
*
* @param documentMap 需要下载的附件集合 map的key对应zip里的文件夹名
* @return ByteArrayOutputStream
*/
public static OutputStream compressFile(Map<String, List<FileInfo>> documentMap, OutputStream outputStream) {
CheckedOutputStream checkedOutputStream = new CheckedOutputStream(outputStream, new CRC32());
ZipOutputStream zipOutputStream = new ZipOutputStream(checkedOutputStream);
try {
for (Map.Entry<String, List<FileInfo>> documentListEntry : documentMap.entrySet()) {
String dirName = documentMap.size() > 1 ? documentListEntry.getKey() : "";
Map<String, Integer> fileNameToLen = new HashMap<>();//记录单个合同号文件夹下每个文件名称出现的次数（对重复文件名重命名）
for (FileInfo document : documentListEntry.getValue()) {
try {
//防止单个文件夹下文件名重复 对重复的文件进行重命名
String documentName = document.getFileName();
if (fileNameToLen.get(documentName) == null) {
fileNameToLen.put(documentName, 1);
} else {
int fileLen = fileNameToLen.get(documentName) + 1;
fileNameToLen.put(documentName, fileLen);
documentName = documentName + "(" + fileLen + ")";
}
String fileName = documentName + "." + document.getSuffix();
if (StringUtils.isNotBlank(dirName)) {
fileName = dirName + File.separator + fileName;
}
addCompressFile(document.getFileInputStream(), fileName, zipOutputStream);
} catch (Exception e) {
logger.info("filesToZip exception :", e);
}
}
}
} catch (Exception e) {
logger.error("filesToZip exception:" + e.getMessage(), e);
}
return outputStream;
}
/**
* 将单个文件写入文件压缩包
*
* @param inputStream 文件输入流
* @param fileName 文件在压缩包中的相对全路径
* @param zipOutputStream 压缩包输出流
*/
private static void addCompressFile(InputStream inputStream, String fileName, ZipOutputStream zipOutputStream) {
try (BufferedInputStream bufferedInputStream = new BufferedInputStream(inputStream)) {
ZipEntry zipEntry = new ZipEntry(fileName);
zipOutputStream.putNextEntry(zipEntry);
byte[] bytes = new byte[1024];
int length;
while ((length = bufferedInputStream.read(bytes)) >= 0) {
zipOutputStream.write(bytes, 0, length);
zipOutputStream.flush();
}
zipOutputStream.closeEntry();
//System.out.println("map size, value is " + RamUsageEstimator.sizeOf(zipOutputStream));
} catch (Exception e) {
logger.info("addFileToZip exception:", e);
throw new RuntimeException(e);
}
}
/**
* 通过网络请求下载zip
*
* @param sourceFilePath 需要压缩的文件路径
* @param response HttpServletResponse
* @param zipName 压缩包名称
* @throws IOException
*/
public static void httpDownloadCompressFile(String sourceFilePath, HttpServletResponse response, String zipName) throws IOException {
File sourceFile = new File(sourceFilePath);
if (!sourceFile.exists()) {
throw new RuntimeException(sourceFilePath + "不存在！");
}
if(StringUtils.isBlank(zipName)){
zipName = sourceFile.getName();
}
try (ServletOutputStream servletOutputStream = response.getOutputStream()){
CompressUtil.compressFile(sourceFile, servletOutputStream);
response.setContentType("application/zip");
response.setHeader("Content-Disposition", "attachment; filename=\"" + zipName + ".zip\"");
servletOutputStream.flush();
}
}
public static void httpDownloadCompressFileOld(String sourceFilePath, HttpServletResponse response, String zipName) throws IOException {
try (ServletOutputStream servletOutputStream = response.getOutputStream()){
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
byte[] zipBytes = byteArrayOutputStream.toByteArray();
response.setContentType("application/zip");
response.setHeader("Content-Disposition", "attachment; filename=\"" + zipName + ".zip\"");
response.setContentLength(zipBytes.length);
servletOutputStream.write(zipBytes);
servletOutputStream.flush();
}
}
/**
* 通过网络请求下载zip
*
* @param sourceFilePath 需要压缩的文件路径
* @param response HttpServletResponse
* @throws IOException
*/
public static void httpDownloadCompressFile(String sourceFilePath, HttpServletResponse response) throws IOException {
httpDownloadCompressFile(sourceFilePath, response, null);
}
/**
* 检查文件名是否已经存在，如果存在，就在文件名后面加上“(1)”，如果文件名“(1)”也存在，则改为“(2)”，以此类推。如果文件名不存在，就直接创建一个新文件。
*
* @param filename 文件名
* @return File
*/
public static File createNewFile(String filename) {
File file = new File(filename);
if (!file.exists()) {
try {
file.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
} else {
String base = filename.substring(0, filename.lastIndexOf("."));
String ext = filename.substring(filename.lastIndexOf("."));
int i = 1;
while (true) {
String newFilename = base + "(" + i + ")" + ext;
file = new File(newFilename);
if (!file.exists()) {
try {
file.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
break;
}
i++;
}
}
return file;
}
}
FileInfo类代码：
/**
* @author fhey
* @date 2023-05-11 21:01:26
* @description: TODO
*/
@Data
public class FileInfo {
private InputStream fileInputStream;
private String suffix;
private String fileName;
private boolean isDirectory;
}
测试压缩并在本地生成文件：
public static void main(String[] args) throws Exception {
//在本地创建压缩文件
CompressUtil.createLocalCompressFile("D:\\书籍\\电子书\\医书", "D:\\test");
}
压缩并在本地生成文件验证结果：
压缩文件并通过http请求下载：
/**
* @author fhey
*/
@RestController
public class TestController {
@GetMapping(value = "/testFileToZip")
public void testFileToZip(HttpServletResponse response) throws IOException {
String zipFileName = "myFiles";
String sourceFilePath = "D:\\picture";
CompressUtil.httpDownloadCompressFile(sourceFilePath,response, zipFileName);
}
}
压缩文件并通过http请求下载验证结果：
