如何在application.properties中配置Spring Boot FTP客户端的服务端地址、账号与密码

1. 新增application.properties配置项 #

首先把FTP相关参数写入配置文件：

# FTP服务端配置
ftp.server.host=192.168.1.100
ftp.server.port=21
ftp.server.username=ftpuser
ftp.server.password=ftppass
# 可选扩展配置
ftp.server.connect-timeout=5000
ftp.server.charset=UTF-8

2. 定义配置属性绑定类 #

创建专门的属性类绑定上述配置，同时在启动类开启属性绑定能力：

import org.springframework.boot.context.properties.ConfigurationProperties;

@ConfigurationProperties(prefix = "ftp.server")
public class FtpServerProperties {
    private String host;
    private Integer port = 21;
    private String username;
    private String password;
    private Integer connectTimeout;
    private String charset;

    // 此处添加所有字段的getter、setter方法
}

启动类添加注解开启属性绑定：

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.properties.EnableConfigurationProperties;

@SpringBootApplication
@EnableConfigurationProperties(FtpServerProperties.class)
public class FtpClientApplication {
    public static void main(String[] args) {
        SpringApplication.run(FtpClientApplication.class, args);
    }
}

3. 封装FTP客户端实例（推荐） #

以常用的Apache Commons Net组件的FTPClient为例，直接初始化可复用的客户端Bean，首先引入依赖：

<dependency>
    <groupId>commons-net</groupId>
    <artifactId>commons-net</artifactId>
    <version>3.9.0</version>
</dependency>

编写客户端配置类：

import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPReply;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class FtpClientConfig {

    private final FtpServerProperties ftpServerProperties;

    // 构造注入配置属性
    public FtpClientConfig(FtpServerProperties ftpServerProperties) {
        this.ftpServerProperties = ftpServerProperties;
    }

    @Bean
    public FTPClient ftpClient() {
        FTPClient ftpClient = new FTPClient();
        try {
            // 连接服务端
            ftpClient.connect(ftpServerProperties.getHost(), ftpServerProperties.getPort());
            // 账号登录
            ftpClient.login(ftpServerProperties.getUsername(), ftpServerProperties.getPassword());
            // 设置基础参数
            ftpClient.setConnectTimeout(ftpServerProperties.getConnectTimeout());
            ftpClient.setControlEncoding(ftpServerProperties.getCharset());
            // 校验连接合法性
            int replyCode = ftpClient.getReplyCode();
            if (!FTPReply.isPositiveCompletion(replyCode)) {
                ftpClient.disconnect();
                throw new RuntimeException("FTP服务连接失败，响应码：" + replyCode);
            }
        } catch (Exception e) {
            throw new RuntimeException("FTPClient初始化失败", e);
        }
        return ftpClient;
    }
}

4. 业务代码使用 #

需要FTP操作的位置直接注入FTPClient即可：

import org.apache.commons.net.ftp.FTPClient;
import org.springframework.stereotype.Service;

@Service
public class FtpOperationService {

    private final FTPClient ftpClient;

    public FtpOperationService(FTPClient ftpClient) {
        this.ftpClient = ftpClient;
    }

    public void testOperate() throws Exception{
        // 执行文件上传、下载、遍历目录等操作
        System.out.println("FTP当前工作目录：" + ftpClient.printWorkingDirectory());
    }
}

需要切换FTP服务端时，仅修改application.properties中ftp.server开头的对应配置项即可，无需修改业务代码。多环境场景下可以结合Spring Boot的profile配置，为不同环境定义独立的配置文件存储FTP参数。

内容的提问来源于stack exchange，提问作者my pochta