Apache FTPClient.retrieveFile方法会将远程文件的内容传输到本地文件中，但不会创建临时文件。

以下是一个使用Apache FTPClient.retrieveFile方法下载远程文件的示例代码：

import org.apache.commons.net.ftp.FTPClient;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;

public class FTPDownloadExample {
    public static void main(String[] args) {
        String server = "ftp.example.com";
        int port = 21;
        String user = "username";
        String password = "password";
        String remoteFile = "/path/to/remote/file.txt";
        String localFile = "/path/to/local/file.txt";

        FTPClient ftpClient = new FTPClient();
        try {
            ftpClient.connect(server, port);
            ftpClient.login(user, password);

            OutputStream outputStream = new FileOutputStream(localFile);
            ftpClient.retrieveFile(remoteFile, outputStream);
            outputStream.close();

            System.out.println("File downloaded successfully.");
        } catch (IOException ex) {
            System.out.println("Error downloading file: " + ex.getMessage());
            ex.printStackTrace();
        } finally {
            try {
                if (ftpClient.isConnected()) {
                    ftpClient.logout();
                    ftpClient.disconnect();
                }
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
    }
}

在上述示例中，将远程文件的内容下载到本地文件中，而不是创建临时文件。