Java实现对zip和rar文件的解压缩

Java提供了ZipInputStream和ZipOutputStream类来实现对zip文件的解压缩和压缩，同时也提供了解压缩RAR文件的开源库，如junrar等。以下是一个示例代码，演示如何使用ZipInputStream和ZipEntry来解压缩zip文件：

import java.io.*;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

public class Unzip {

    public static void main(String[] args) throws IOException {
        String zipFilePath = "path/to/zip/file.zip";
        String destDirectory = "path/to/destination/folder";
        unzip(zipFilePath, destDirectory);
    }

    public static void unzip(String zipFilePath, String destDirectory) throws IOException {
        File destDir = new File(destDirectory);
        if (!destDir.exists()) {
            destDir.mkdir();
        }
        ZipInputStream zipIn = new ZipInputStream(new FileInputStream(zipFilePath));
        ZipEntry entry = zipIn.getNextEntry();
        while (entry != null) {
            String filePath = destDirectory + File.separator + entry.getName();
            if (!entry.isDirectory()) {
                extractFile(zipIn, filePath);
            } else {
                File dir = new File(filePath);
                dir.mkdir();
            }
            zipIn.closeEntry();
            entry = zipIn.getNextEntry();
        }
        zipIn.close();
    }

    private static void extractFile(ZipInputStream zipIn, String filePath) throws IOException {
        BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(filePath));
        byte[] bytesIn = new byte[4096];
        int read = 0;
        while ((read = zipIn.read(bytesIn)) != -1) {
            bos.write(bytesIn, 0, read);
        }
        bos.close();
    }
}

对于RAR文件的解压缩，可以使用开源库junrar：

import com.github.junrar.Archive;
import com.github.junrar.exception.RarException;
import com.github.junrar.impl.FileVolumeManager;
import com.github.junrar.rarfile.FileHeader;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class Unrar {

    public static void main(String[] args) throws RarException, IOException {
        String rarFilePath = "path/to/rar/file.rar";
        String destDirectory = "path/to/destination/folder";
        unrar(rarFilePath, destDirectory);
    }

    public static void unrar(String rarFilePath, String destDirectory) throws RarException, IOException {
        Archive archive = new Archive(new FileVolumeManager(new File(rarFilePath)));
        FileHeader fileHeader = archive.nextFileHeader();
        while (fileHeader != null) {
            String filePath = destDirectory + File.separator + fileHeader.getFileNameString().trim();
            if (fileHeader.isDirectory()) {
                File dir = new File(filePath);
                dir.mkdirs();
            } else {
                FileOutputStream fos = new FileOutputStream(new File(filePath));
                archive.extractFile(fileHeader, fos);
                fos.close();
            }
            fileHeader = archive.nextFileHeader();
        }
        archive.close();
    }
}