<!-- sftp -->
<dependency>
    <groupId>com.jcraft</groupId>
    <artifactId>jsch</artifactId>
    <version>0.1.55</version>
</dependency>
<!-- commons-pool2 -->
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-pool2</artifactId>
    <version>2.6.1</version>
</dependency>

sftp:
  host: server02 # 服务器ip
  port: 22 # ssh端口
  username: demofile # 用户名
  password: demo # 密码
  # 连接池参数
  pool:
    max-total: 10
    max-idle: 10
    min-idle: 5

package com.example.ftp;

import com.jcraft.jsch.ChannelSftp;
import lombok.Data;
import org.apache.commons.pool2.impl.GenericObjectPoolConfig;
import org.springframework.boot.context.properties.ConfigurationProperties;

@Data
@ConfigurationProperties(prefix = "sftp")
public class SftpProperties {

    private String host;
    private int port = 22;
    private String username = "root";
    private String password = "root";
    private Pool pool = new Pool();

    public static class Pool extends GenericObjectPoolConfig<ChannelSftp> {

        private int maxTotal = DEFAULT_MAX_TOTAL;
        private int maxIdle = DEFAULT_MAX_IDLE;
        private int minIdle = DEFAULT_MIN_IDLE;

        public Pool() {
            super();
        }
        @Override
        public int getMaxTotal() {
            return maxTotal;
        }
        @Override
        public void setMaxTotal(int maxTotal) {
            this.maxTotal = maxTotal;
        }
        @Override
        public int getMaxIdle() {
            return maxIdle;
        }
        @Override
        public void setMaxIdle(int maxIdle) {
            this.maxIdle = maxIdle;
        }
        @Override
        public int getMinIdle() {
            return minIdle;
        }
        @Override
        public void setMinIdle(int minIdle) {
            this.minIdle = minIdle;
        }

    }

}

package com.example.ftp;
import com.example.exception.ProjectException;
import com.jcraft.jsch.ChannelSftp;
import com.jcraft.jsch.JSch;
import com.jcraft.jsch.JSchException;
import com.jcraft.jsch.Session;
import lombok.Data;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.pool2.BasePooledObjectFactory;
import org.apache.commons.pool2.PooledObject;
import org.apache.commons.pool2.impl.DefaultPooledObject;

import java.util.Properties;

@Data
@Slf4j
public class SftpFactory extends BasePooledObjectFactory<ChannelSftp> {

    private SftpProperties properties;

    public SftpFactory(SftpProperties properties) {
        this.properties = properties;
    }

    @Override
    public ChannelSftp create() {
        try {
            JSch jsch = new JSch();
            Session sshSession = jsch.getSession(properties.getUsername(), properties.getHost(), properties.getPort());
            sshSession.setPassword(properties.getPassword());
            Properties sshConfig = new Properties();
            sshConfig.put("StrictHostKeyChecking", "no");
            sshSession.setConfig(sshConfig);
            sshSession.connect();
            ChannelSftp channel = (ChannelSftp) sshSession.openChannel("sftp");
            channel.connect();
            return channel;
        } catch (JSchException e) {
            throw new ProjectException("连接sfpt失败", e);
        }
    }

    @Override
    public PooledObject<ChannelSftp> wrap(ChannelSftp channelSftp) {
        return new DefaultPooledObject<>(channelSftp);
    }

    // 销毁对象
    @Override
    public void destroyObject(PooledObject<ChannelSftp> p) {
        ChannelSftp channelSftp = p.getObject();
        channelSftp.disconnect();
    }

}

package com.example.ftp;

import com.example.exception.ProjectException;
import com.jcraft.jsch.ChannelSftp;
import lombok.Data;
import org.apache.commons.pool2.impl.GenericObjectPool;

@Data
public class SftpPool {

    private GenericObjectPool<ChannelSftp> pool;

    public SftpPool(SftpFactory factory) {
        this.pool = new GenericObjectPool<>(factory, factory.getProperties().getPool());
    }

    /**
     * 获取一个sftp连接对象
     * @return sftp连接对象
     */
    public ChannelSftp borrowObject() {
        try {
            return pool.borrowObject();
        } catch (Exception e) {
            throw new ProjectException("获取ftp连接失败", e);
        }
    }

    /**
     * 归还一个sftp连接对象
     * @param channelSftp sftp连接对象
     */
    public void returnObject(ChannelSftp channelSftp) {
        if (channelSftp!=null) {
            pool.returnObject(channelSftp);
        }
    }

}

package com.example.ftp;

import com.example.exception.ProjectException;
import com.example.util.ByteUtil;
import com.jcraft.jsch.ChannelSftp;
import com.jcraft.jsch.SftpException;

import java.io.InputStream;

// sftp辅助类
public class SftpHelper {

    private SftpPool pool;

    public SftpHelper(SftpPool pool) {
        this.pool = pool;
    }

    /**
     * 下载文件
     * @param dir 远程目录
     * @param name 远程文件名
     * @return 文件字节数组
     */
    public byte[] download(String dir, String name) {
        ChannelSftp sftp = pool.borrowObject();
        try {
            sftp.cd(dir);
            InputStream in = sftp.get(name);
            return ByteUtil.inputStreamToByteArray(in);
        } catch (SftpException e) {
            throw new ProjectException("sftp下载文件出错", e);
        } finally {
            pool.returnObject(sftp);
        }
    }

    /**
     * 上传文件
     * @param dir 远程目录
     * @param name 远程文件名
     * @param in 输入流
     */
    public void upload(String dir, String name, InputStream in) {
        ChannelSftp sftp = pool.borrowObject();
        try {
            mkdirs(sftp, dir);
            sftp.cd(dir);
            sftp.put(in, name);
        } catch (SftpException e) {
            throw new ProjectException("sftp上传文件出错", e);
        } finally {
            pool.returnObject(sftp);
        }
    }

    /**
     * 删除文件
     * @param dir 远程目录
     * @param name 远程文件名
     */
    public void delete(String dir, String name) {
        ChannelSftp sftp = pool.borrowObject();
        try {
            sftp.cd(dir);
            sftp.rm(name);
        } catch (SftpException e) {
            throw new ProjectException("sftp删除文件出错", e);
        } finally {
            pool.returnObject(sftp);
        }
    }

    /**
     * 递归创建多级目录
     * @param dir 多级目录
     */
    private void mkdirs(ChannelSftp sftp, String dir) {
        String[] folders = dir.split("/");
        try {
            sftp.cd("/");
            for (String folder: folders) {
                if (folder.length()>0) {
                    try {
                        sftp.cd(folder);
                    } catch (Exception e) {
                        sftp.mkdir(folder);
                        sftp.cd(folder);
                    }
                }
            }
        } catch (SftpException e) {
            throw new ProjectException("sftp创建目录出错", e);
        }
    }

}

package com.example.config;

import com.example.ftp.SftpFactory;
import com.example.ftp.SftpHelper;
import com.example.ftp.SftpPool;
import com.example.ftp.SftpProperties;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

// ftp配置
@Configuration
@EnableConfigurationProperties(SftpProperties.class)
public class SftpConfig {

    // 工厂
    @Bean
    public SftpFactory sftpFactory(SftpProperties properties) {
        return new SftpFactory(properties);
    }

    // 连接池
    @Bean
    public SftpPool sftpPool(SftpFactory sftpFactory) {
        return new SftpPool(sftpFactory);
    }

    // 辅助类
    @Bean
    public SftpHelper sftpHelper(SftpPool sftpPool) {
        return new SftpHelper(sftpPool);
    }

}