典型:各种连接池
public class ConnectionPool { private Vector<Connection> pool; /*公有属性*/ private String url = "jdbc:mysql://localhost:3306/test"; private String username = "root"; private String password = "root"; private String driverClassName = "com.mysql.jdbc.Driver"; private int poolSize = 100; private static ConnectionPool instance = null; Connection conn = null; /*构造方法,做一些初始化工作*/ private ConnectionPool() { pool = new Vector<Connection>(poolSize); for (int i = 0; i < poolSize; i++) { try { Class.forName(driverClassName); conn = DriverManager.getConnection(url, username, password); pool.add(conn); } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); } } } /* 返回连接到连接池 */ public synchronized void release() { pool.add(conn); } /* 返回连接池中的一个数据库连接 */ public synchronized Connection getConnection() { if (pool.size() > 0) { Connection conn = pool.get(0); pool.remove(conn); return conn; } else { return null; } } }