java ftp连接池

Java FTP连接池是一种用于管理FTP连接的工具。它可以通过维护一组FTP连接，从而实现快速和高效地连接到FTP服务器。

使用Java FTP连接池，可以避免频繁地创建和销毁FTP连接，从而减少资源消耗和提高性能。此外，连接池还可以控制连接的数量和超时时间，以确保连接的稳定性和可靠性。

下面是一个基于Apache Commons Net库实现的Java FTP连接池示例：

import java.io.IOException;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;

import org.apache.commons.net.ftp.FTPClient;

public class FtpConnectionPool {
    private static final int DEFAULT_POOL_SIZE = 10;
    private final BlockingQueue<FTPClient> pool;

    // 初始化连接池
    public FtpConnectionPool(int poolSize) {
        pool = new ArrayBlockingQueue<>(poolSize);
        for (int i = 0; i < poolSize; i++) {
            pool.offer(createFtpClient());
        }
    }

    // 获取FTP连接
    public FTPClient borrowObject() {
        FTPClient ftpClient = null;
        try {
            ftpClient = pool.take();
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
        }
        if (ftpClient == null) {
            ftpClient = createFtpClient();
        }
        return ftpClient;
    }

    // 归还FTP连接
    public void returnObject(FTPClient ftpClient) {
        if (ftpClient != null) {
            pool.offer(ftpClient);
        }
    }

    // 销毁连接池
    public void destroy() {
        for (FTPClient ftpClient : pool) {
            try {
                ftpClient.logout();
                ftpClient.disconnect();
            } catch (IOException e) {
                // ignore
            }
        }
        pool.clear();
    }

    // 创建FTP连接
    private FTPClient createFtpClient() {
        FTPClient ftpClient = new FTPClient();
        try {
            ftpClient.connect("ftp.example.com");
            ftpClient.login("username", "password");
            ftpClient.enterLocalPassiveMode();
        } catch (IOException e) {
            throw new RuntimeException("Failed to create FTP client", e);
        }
        return ftpClient;
    }
}

使用示例：

FtpConnectionPool connectionPool = new FtpConnectionPool(10);
FTPClient ftpClient = connectionPool.borrowObject();
try {
    // do something with ftpClient
} finally {
    connectionPool.returnObject(ftpClient);
}
connectionPool.destroy();
``