下面是一个使用Apache HttpUtils下载文件的示例代码：

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.util.EntityUtils;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class FileDownloader {

    public static void main(String[] args) {
        String fileUrl = "http://example.com/file.txt";
        String savePath = "C:/path/to/save/file.txt";

        try {
            downloadFile(fileUrl, savePath);
            System.out.println("File downloaded successfully.");
        } catch (IOException e) {
            System.out.println("Failed to download file: " + e.getMessage());
        }
    }

    public static void downloadFile(String fileUrl, String savePath) throws IOException {
        CloseableHttpClient httpClient = HttpClientBuilder.create().build();
        HttpGet httpGet = new HttpGet(fileUrl);

        HttpResponse response = httpClient.execute(httpGet);
        HttpEntity entity = response.getEntity();

        if (entity != null) {
            try (InputStream inputStream = entity.getContent();
                 OutputStream outputStream = new FileOutputStream(savePath)) {

                byte[] buffer = new byte[1024];
                int bytesRead;
                while ((bytesRead = inputStream.read(buffer)) != -1) {
                    outputStream.write(buffer, 0, bytesRead);
                }
            } finally {
                EntityUtils.consume(entity);
            }
        }
    }
}

以上示例代码使用Apache HttpUtils库下载文件。首先，创建一个CloseableHttpClient实例。然后，创建HttpGet对象，设置文件的URL。接下来，执行HttpGet请求并获取HttpResponse对象。通过HttpResponse对象可以获取文件的HttpEntity。如果HttpEntity不为null，我们可以使用输入流从HttpEntity中读取文件内容，并将其写入输出流中。最后，我们关闭输入流、输出流和HttpEntity。

在main方法中，我们可以指定文件的URL和保存路径，然后调用downloadFile方法来下载文件。如果下载成功，将打印"File downloaded successfully."；如果下载失败，将打印"Failed to download file: ..."并输出错误信息。