Java JDBC连接池设计与优化实例-蒲公英云

Java JDBC连接池设计与优化实例

原创矫情吗；* 2024-09-21 02:39 166阅读 0赞

在Java开发中，JDBC（Java Database Connectivity）连接池是一种常用的设计模式，它可以有效管理和复用数据库连接。

以下是一个简单的Java JDBC连接池设计与优化实例：

创建连接池类（如ConnectionPool.java）

import java.sql.Connection;
import java.sql.DriverManager;
import java.util.concurrent.Executors;
import java.util.concurrent.RejectedExecutionException;
public class ConnectionPool {
    private static final String DB_URL = "jdbc:mysql://localhost:3306/testdb";
    private static final int MAX_CONNECTIONS = 10; // 连接池最大连接数
    private static final int MIN_CONNECTIONS = 5; // 连接池最小连接数
    private ConnectionPool() { } // 构造器私有化，防止外部创建
    public synchronized static Connection getConnection() {
        Connection connection = null;
        try {
            // 判断连接池状态
            if (connectionsInUse() >= MAX_CONNECTIONS) {
                // 若连接已经满，等待新的连接释放
                connection = waitAndAcquireConnection();
            } else {
                // 若连接池中还有可用连接，直接获取
                connection = DriverManager.getConnection(DB_URL);
            }
        } catch (Exception e) {
            System.out.println("Error occurred while acquiring database connection: " + e.getMessage());
            if (connection != null) { // 如果已经获取到的连接，关闭释放
                try {
                    connection.close();
                } catch (SQLException se) {
                    System.out.println("Failed to close database connection after error: " + se.getMessage());
                }
            }
        }
        return connection;
    }
    private static boolean connectionsInUse() {
        ConnectionPool pool = ConnectionPool.getInstance();
        if (pool != null && !pool.isEmpty()) {
            // 如果连接池中有连接，则返回true
            return true;
        }
        return false;
    }
    private static Connection waitAndAcquireConnection() throws InterruptedException, RejectedExecutionException {
        // 将获取连接的任务放入线程池中，等待被处理
        Executor executor = Executors.newSingleThreadExecutor();
        executor.execute(() -> {
            try {
                // 获取数据库连接
                Connection connection = DriverManager.getConnection(DB_URL);
                // 从连接池中移除这个已使用的连接
                ConnectionPool.getInstance().removeConnection(connection);
                // 连接返回，用于后续操作
                return connection;
            } catch (Exception e) {
                System.out.println("Error occurred while acquiring database connection: " + e.getMessage());
                // 如果获取到的连接有问题，需要关闭释放
                try {
                    if (connection != null) {
                        connection.close();
                    }
                } catch (SQLException se) {
                    System.out.println("Failed to close database connection after error: " + se.getMessage());
                }
            }
        }));
    }
    private static ConnectionPool getInstance() {
        // 若连接池尚未创建，创建一个新的连接池实例
        if (ConnectionPool.pool == null) {
            ConnectionPool.pool = new ConnectionPool();
        }
        return ConnectionPool.pool;
    }
    public static void destroy() {
        // 如果连接池已经创建，销毁当前的连接池实例
        if (ConnectionPool.pool != null) {
            ConnectionPool.pool.clear();
            ConnectionPool.pool = null;
        }
    }
}