java实现文件压缩下载

文件压缩下载

package com.ruoyi.utils;
import com.ruoyi.common.utils.DateUtils;
import com.ruoyi.common.utils.StringUtils;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.UUID;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;
/**
 * @Auther: ZHANG PU
 * @Date: 2022/6/7 18:01
 * @Description:
 */
public class ZipUtils {
    private static final int BUFFER_SIZE = 2 * 1024;

    /**
     * 压缩成ZIP 方法1
     *
     * @param srcDir           压缩文件夹路径
     * @param out              压缩文件输出流
     * @param KeepDirStructure 是否保留原来的目录结构,true:保留目录结构;
     *                         false:所有文件跑到压缩包根目录下(注意：不保留目录结构可能会出现同名文件,会压缩失败)
     * @throws RuntimeException 压缩失败会抛出运行时异常
     */
    public static void toZip(String srcDir, OutputStream out, boolean KeepDirStructure) throws RuntimeException {
        long start = System.currentTimeMillis();
        ZipOutputStream zos = null;
        try {
            zos = new ZipOutputStream(out);
            File sourceFile = new File(srcDir);
            compress(sourceFile, zos, sourceFile.getName(), KeepDirStructure);
            long end = System.currentTimeMillis();
            System.out.println("压缩完成，耗时：" + (end - start) + " ms");
        } catch (Exception e) {
            throw new RuntimeException("zip error from ZipUtils", e);
        } finally {
            if (zos != null) {
                try {
                    zos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    /**
     * 压缩成ZIP 方法2
     *
     * @param srcFiles 需要压缩的文件列表
     * @param out      压缩文件输出流
     * @throws RuntimeException 压缩失败会抛出运行时异常
     */
    public static void toZip(List srcFiles, OutputStream out) throws RuntimeException {
        long start = System.currentTimeMillis();
        ZipOutputStream zos = null;
        try {
            zos = new ZipOutputStream(out);
            for (File srcFile : srcFiles) {
                byte[] buf = new byte[BUFFER_SIZE];
                zos.putNextEntry(new ZipEntry(srcFile.getName()));
                int len;
                FileInputStream in = new FileInputStream(srcFile);
                while ((len = in.read(buf)) != -1)
                {
                    zos.write(buf, 0, len);
                }
                zos.closeEntry();
                in.close();
            }
            long end = System.currentTimeMillis();
        } catch (Exception e) {
            throw new RuntimeException("zip error from ZipUtils", e);
        } finally {
            if (zos != null) {
                try {
                    zos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }


    /**
     * 递归压缩方法
     *
     * @param sourceFile       源文件
     * @param zos              zip输出流
     * @param name             压缩后的名称
     * @param KeepDirStructure 是否保留原来的目录结构,true:保留目录结构;
     *                         false:所有文件跑到压缩包根目录下(注意：不保留目录结构可能会出现同名文件,会压缩失败)
     * @throws Exception
     */
    private static void compress(File sourceFile, ZipOutputStream zos, String name, boolean KeepDirStructure) throws Exception {
        byte[] buf = new byte[BUFFER_SIZE];
        if (sourceFile.isFile()) {
            // 向zip输出流中添加一个zip实体，构造器中name为zip实体的文件的名字
            zos.putNextEntry(new ZipEntry(name));
            // copy文件到zip输出流中
            int len;
            FileInputStream in = new FileInputStream(sourceFile);
            while ((len = in.read(buf)) != -1)
            {
                zos.write(buf, 0, len);
            }
            zos.closeEntry();
            in.close();
        } else {
            File[] listFiles = sourceFile.listFiles();
            if (listFiles == null || listFiles.length == 0)
            {
                // 需要保留原来的文件结构时,需要对空文件夹进行处理
                if (KeepDirStructure)
                {
                    // 空文件夹的处理
                    zos.putNextEntry(new ZipEntry(name + "/"));
                    // 没有文件，不需要文件的copy
                    zos.closeEntry();
                }

            } else {
                for (File file : listFiles)
                {
                    // 判断是否需要保留原来的文件结构
                    if (KeepDirStructure)
                    {
                        // 注意：file.getName()前面需要带上父文件夹的名字加一斜杠,
                        // 不然最后压缩包中就不能保留原来的文件结构,即：所有文件都跑到压缩包根目录下了
                        compress(file, zos, name + "/" + file.getName(), KeepDirStructure);
                    } else {
                        compress(file, zos, file.getName(), KeepDirStructure);
                    }
                }
            }
        }
    }

    public static void main(String[] args) throws Exception {
        FileOutputStream fos1 = new FileOutputStream(new File("c:/mytest01.zip"));
        ZipUtils.toZip("D:/log", fos1, true);
        List fileList = new ArrayList<>();
        fileList.add(new File("D:/Java/jdk1.7.0_45_64bit/bin/jar.exe"));
        fileList.add(new File("D:/Java/jdk1.7.0_45_64bit/bin/java.exe"));
        FileOutputStream fos2 = new FileOutputStream(new File("c:/mytest02.zip"));
        ZipUtils.toZip(fileList, fos2);
    }

    /**
     * 压缩图片下载
     * @param request
     * @param response
     * @param fileUrl
     * @throws Exception
     */
    public static void downImageZip(HttpServletRequest request, HttpServletResponse response,List fileUrl) throws Exception{
        //创建临时文件夹
        String rootPath = request.getSession().getServletContext().getRealPath("/");
        File temDir = new File(rootPath + "/" + UUID.randomUUID().toString().replaceAll("-", ""));
        if(!temDir.exists())
        {
            temDir.mkdirs();
        }
        //生成需要下载的文件，存放在临时文件夹内
        for (String url : fileUrl)
        {
            if(StringUtils.isNotBlank(url))
            {
                String fileName = url.substring(url.lastIndexOf("/") + 1, url.length());
                byte[] btImg = UrlConverStreamUtils.getImageFromNetByUrl(url);
                FileOutputStream fops = new FileOutputStream(temDir.getPath()+"/"+fileName);
                fops.write(btImg);
                fops.flush();
                fops.close();
            }
        }
        //设置response的header
        response.setContentType("application/zip");
        response.setHeader("Content-Disposition", "attachment; filename="+ DateUtils.dateTime(new Date()) +".zip");
        // 下载zip压缩包,不需要保留目录结构
        ZipUtils.toZip(temDir.getPath(), response.getOutputStream(),false);
        //删除临时文件和文件夹
        File[] listFiles = temDir.listFiles();
        for (int i = 0; i < listFiles.length; i++)
        {
            listFiles[i].delete();
        }
        temDir.delete();
    }
}