Steps

导入依赖
重写Apache Commons Pools2 的方法
测试

导入依赖

我还用了 Hutool 的包，和SpringBoot的基础jar包

<dependencies>
    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-pool2</artifactId>
        <version>2.11.1</version>
    </dependency>
    <dependency>
        <groupId>com.jcraft</groupId>
        <artifactId>jsch</artifactId>
        <version>0.1.55</version>
    </dependency>
</dependencies>

重写Apache Commons Pools2 的方法

所有的类

继承BasePooledObjectFactory 这个类，实现我们自己的sftp 工厂（SftpPooledObjectFactory）

主要重写下面四个方法

create ：创建我们需要的连接对象
warp ：将我们创建的对象，包装成PooledObject对象
另外两个顾名思义

总之这个 Factory 是抽象工厂方法的实现，对 sftp 连接对象的生命周期进行管理

用了 ConfigurationProperties 去配置 sftp 连接的参数

继承ObjectPool对象

实现连接池的配置，具体配置代码，还有一个拒绝策略

配置文件

	@Slf4j
@Component
public class SftpPooledObjectFactory extends BasePooledObjectFactory<ChannelSftp> {


    public SftpPooledObjectFactory() {}

    @Override
    public ChannelSftp create() throws Exception {
        return sftpCreate();
    }

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


    @Override
    public void destroyObject(PooledObject<ChannelSftp> p) throws Exception {
        ChannelSftp object = p.getObject();
        if (ObjectUtil.isNotNull(object)||(object.isConnected())) {
            object.disconnect();
            super.destroyObject(p);
        }
    }

    @Override
    public boolean validateObject(PooledObject<ChannelSftp> p) {
        ChannelSftp object = p.getObject();
        return object.isConnected();
    }

    private ChannelSftp sftpCreate() throws JSchException {
        SftpContractProperties properties = SpringUtil.getBean("sftpContractProperties");
        JSch jsch = new JSch();
        Session session = jsch.getSession(properties.getUsername(), properties.getHostname(), properties.getPort());
        session.setPassword(properties.getPassword());

        Properties config = new Properties();
        config.put("StrictHostKeyChecking", "no");
        session.setConfig(config);
        int sftpTimeout = 5000;
        session.setTimeout(sftpTimeout);
        session.connect();
        log.debug("sftp session connected");

        log.debug("opening channel");
        ChannelSftp channel = (ChannelSftp) session.openChannel("sftp");
        channel.connect();
        log.debug("connected successfully");
        return channel;

    }

}

@Slf4j
@Component
public class SftpPool implements ObjectPool<ChannelSftp> {
    private GenericObjectPool<ChannelSftp> sftpConnectPool;

    private final SftpPooledObjectFactory factory;


    @Autowired
    public SftpPool(SftpPooledObjectFactory factory) {
        this.factory = factory;

        AbandonedConfig abandonedConfig = new AbandonedConfig();
        abandonedConfig.setRemoveAbandonedOnMaintenance(true);
        abandonedConfig.setRemoveAbandonedOnBorrow(true);
        this.sftpConnectPool = new GenericObjectPool<>(factory, getPoolConfiguration(), abandonedConfig);
    }


    @Override
    public void addObject() throws Exception, IllegalStateException, UnsupportedOperationException {
        sftpConnectPool.addObject();
    }

    @Override
    public ChannelSftp borrowObject() throws Exception, NoSuchElementException, IllegalStateException {
        return sftpConnectPool.borrowObject();
    }


    @Override
    public void clear() throws Exception, UnsupportedOperationException {
        sftpConnectPool.clear();
    }

    @Override
    public void close() {
        sftpConnectPool.close();
    }

    @Override
    public int getNumActive() {
        return sftpConnectPool.getNumActive();
    }

    @Override
    public int getNumIdle() {
        return sftpConnectPool.getNumIdle();
    }

    @Override
    public void invalidateObject(ChannelSftp obj) throws Exception {
        sftpConnectPool.invalidateObject(obj);
    }

    @Override
    public void returnObject(ChannelSftp obj) throws Exception {
        sftpConnectPool.returnObject(obj);
    }

    private GenericObjectPoolConfig<ChannelSftp> getPoolConfiguration() {

        SftpPoolProperties poolProperties = SpringUtil.getBean("sftpPoolProperties");

        GenericObjectPoolConfig<ChannelSftp> config = new GenericObjectPoolConfig<>();
        config.setMinIdle(poolProperties.getMinIdle());
        config.setMaxIdle(poolProperties.getMaxIdle());
        config.setMaxTotal(poolProperties.getMaxActive());
        config.setMaxWait(Duration.ofMillis(poolProperties.getMaxWait()));
        config.setTestOnBorrow(poolProperties.isTestOnBorrow());
        config.setTestOnReturn(poolProperties.isTestOnReturn());
        config.setTestWhileIdle(poolProperties.isTestWhileIdle());

        config.setEvictionPolicyClassName(SftpEvictionPolicy.class.getName());


        return config;
    }
}

@Slf4j
@Component("sftpEvictionPolicy")
public class SftpEvictionPolicy implements EvictionPolicy<ChannelSftp> {
    @Override
    public boolean evict(EvictionConfig config, PooledObject<ChannelSftp> underTest, int idleCount) {
        try {
            // 连接失效时进行驱逐
            if (!underTest.getObject().isConnected()) {
                log.warn("connect time out, evict the connection. time={}",System.currentTimeMillis() - underTest.getLastReturnTime());
                return true;
            }
        }catch (Exception e){
            return true;
        }
        return false;
    }
}

@Data
@ConfigurationProperties(prefix = SftpContractProperties.SFTP_PREFIX)
@Component
public class SftpContractProperties {
    final static String SFTP_PREFIX = "zxh.sftp";

    private String username;
    private String password;
    private String hostname;
    private int port;
}

@ConfigurationProperties(SftpPoolProperties.POOL_CONFIG_PREFIX)
@Component
@Data
public class SftpPoolProperties {
    public static final String POOL_CONFIG_PREFIX = "zxh.sftp.pool";

    private int minIdle;
    private int maxIdle;
    private int maxActive;
    private long maxWait;
    private boolean testOnBorrow;
    private boolean testOnReturn;
    private boolean testWhileIdle;
    private long timeBetweenEvictionRuns;
}

@Slf4j
@Component
public class SftpUtil {

    @Autowired
    private SftpPool sftpPool;

    private ChannelSftp sftp;

    public SftpUtil() {
    }

    public void showPwd() throws Exception {
        String pwd = getClient().pwd();
        log.info("pwd:{}", pwd);
        if (null != sftp) {
            disConnected();
        }
    }
    private ChannelSftp getClient() throws Exception {
        log.info("拿到sftp");
        sftp = sftpPool.borrowObject();
        return sftp;
    }
    public void disConnected() throws Exception {
        sftpPool.returnObject(sftp);
        log.info("归还sftp");
    }


}

Junit 测试

@RunWith(SpringRunner.class)
@SpringBootTest(classes = LearningApplication.class)
@Slf4j
public class SftpTest {


    @Autowired
    private SftpPool sftpPool;

    @Test
    public void testSftpConnection() throws Exception {
        SftpUtil sftpUtil = SpringUtil.getBean("sftpUtil");
        log.info("================================================================");
        isConnected();
        for (int i = 0; i < 100; i++) {
            sftpUtil.showPwd();
            isConnected();
        }
        int numActive2 = sftpPool.getNumActive();
        log.info("连接数量 numActive:{}", numActive2);
//        sftpUtil.returnObject();
        isConnected();
        int numActive1 = sftpPool.getNumActive();
        log.info("连接数量 numActive:{}", numActive1);
        log.info("================================================================");
        
    }
    private void isConnected() {
        SftpUtil sftpUtil = SpringUtil.getBean("sftpUtil");
        int numActive = sftpPool.getNumActive();
        log.info("连接数量 numActive:{}", numActive);
        if (sftpUtil.isConnect()) {
            log.info("Sftp connection established");
        } else {
            log.info("Sftp connection closed");

        }
    }

}

测试结果

结果错乱，因为多线程没有加锁，不过能跑成功即可

Q：遇到的坑

多线程不能运行 @Autowired 中注入的Bean,需要用SpringUitl 从容器中拿，再运行。
Junit 不能多线程运行bean ，我会的方式是不行的，需要增加配置，或者让Junit 等待。
Spring中的注入问题，我有的用 @Autowired ，有的用构造方法注入,并不是随意的，因为@autowired 注入失败，才用构造方法的。失败原因，了解但是不深入。

TODO

多线程使用自定义sftp线程池的优化。用 ThreadLocal
让 Junit 多线程执行 Bean
深入研究bean的注入

Steps

导入依赖

重写Apache Commons Pools2 的 方法

Junit 测试

测试结果

Q：遇到的坑

TODO

重写Apache Commons Pools2 的方法