为什么我的 ScheduledExecutorService 这样工作？

Question

我的线程程序不起作用，因为我希望它起作用。

首先是我的主类，从那里开始我的线程：

import static java.lang.Thread.currentThread;

public class Main {

public static void main(String[] args) throws IOException, NamingException, ClassNotFoundException {

    Properties property = new Properties();

    property.load(new FileReader(new File(args[0])));

    DataSource ds = DataSource.newInstance(property);

    Class.forName("org.postgresql.Driver");

    ConnectionPool connectionPool = new ConnectionPool();

    System.out.println(currentThread().getName());

    ConnectionPoolManager manager = new ConnectionPoolManager(connectionPool, ds);

    manager.start();

    }

}

这是我的 ConnectionPool 类

package com.telbook.connectionPooling;

import java.sql.Connection;

import java.sql.SQLException;

import java.util.ArrayList;

import java.util.List;

public class ConnectionPool {

private List<PoolObject> poolObjects = new ArrayList<>();

public List<PoolObject> getPoolObjects() {

    return poolObjects;

}

public void setPoolObjects(List<PoolObject> poolObjects) {

    this.poolObjects = poolObjects;

}

public void put(Connection connection) {

    PoolObject poolObject = new PoolObject();

    poolObject.setConnection(connection);

    poolObjects.add(poolObject);

}

public Connection getConnection() throws SQLException {

    for (PoolObject object: poolObjects) {

        if (!object.getInUse() && object.getConnection()!=null) {

            if (!object.getConnection().isClosed()) {

                if (object.getConnection().isValid(50)) {

                    object.setInUse(true);

                    return object.getConnection();

                }

            }

        }

    }

    return null;

}

}

Answer 1

ArrayList不是线程安全的，调度线程池中的线程可能无法获取最新元素，请尝试使用线程安全版本List：private&nbsp;List<PoolObject>&nbsp;poolObjects&nbsp;=&nbsp;Collections.synchronizedList(new&nbsp;ArrayList<PoolObject>());