FTPClient 判断文件是否存在

FTPClient 所在包 commons-net-3.6.jar

判断代码如下：

import java.io.IOException;

import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPReply;
import org.junit.Before;
import org.junit.Test;


public class FTPClientTest {

	private static String url = "127.0.0.1";
	private static int port = 21;
	private static String uname = "admin";
	private static String upass = "123456";

	private FTPClient client;

	
	@Before
	public void initClient() throws IOException {
		client = new FTPClient();
		client.connect(url, port);
		client.login(uname, upass);
		int reply = client.getReplyCode();
		if (!FTPReply.isPositiveCompletion(reply)) {
			client.disconnect();
		}

		// 使用被动模式
		client.enterLocalPassiveMode();
	}

	
	@Test
	public void checkFileExists() throws IOException {

		boolean connected = client.isConnected();
		if (!connected) {
			System.out.println("客户端未连接成功！");
		}

		// 进入当前用户根目录，方便listNames方法从用户根路径查找文件
		client.changeWorkingDirectory("/");
		// 文件再当前用户下的全路径
		String path = "demo/pdf/demo.jpeg";
		
		// 当前文件存在时，会返回文件路径
		String[] listNames = client.listNames(path);
		boolean existsFlag = listNames.length > 0;
		System.out.println(existsFlag ? "文件存在" : "文件不存在");

	}

}

以上代码如果存在问题，欢迎留言。