在Java中解壓ZIP文件到指定目錄可以使用java.util.zip包中的ZipInputStream類和ZipEntry類來實現。下面是一個示例代碼：

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

public class UnzipExample {

    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 {
        try (FileOutputStream fos = new FileOutputStream(filePath)) {
            byte[] buffer = new byte[1024];
            int length;
            while ((length = zipIn.read(buffer)) > 0) {
                fos.write(buffer, 0, length);
            }
        }
    }

    public static void main(String[] args) {
        String zipFilePath = "example.zip";
        String destDirectory = "unzipped";
        
        try {
            unzip(zipFilePath, destDirectory);
            System.out.println("ZIP file has been successfully extracted to " + destDirectory);
        } catch (IOException e) {
            System.out.println("Error occurred during ZIP file extraction: " + e.getMessage());
        }
    }
}

在上面的示例代碼中，unzip方法接收ZIP文件的路徑和目標目錄的路徑作為參數，然后使用ZipInputStream類逐個解析ZIP文件中的條目，并根據條目的類型（文件或目錄）進行解壓操作。解壓文件時，調用extractFile方法來將文件內容寫入到目標目錄中。最后，在main方法中調用unzip方法來解壓ZIP文件到指定目錄。