public class MyDataSource {
	private LinkedList<Connection> pool = new LinkedList(); //連結串列放連線池用
	private static final int INIT_CONNECTIONS = 10;//初始化連線數
	private  static final String DRIVER_CLASS="com.mysql.jdbc.Driver";//驅動
	private  static final String USER="";//使用者
	private  static final String PASSWORD=
 
"";// 密碼
	private  static final String URL="";//地址

	private Lock lock = new ReentrantLock();
	Condition c1 = lock.newCondition();

	static {
		try {
			Class.forName(DRIVER_CLASS);//載入驅動
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
	}
	public MyDataSource() {
		for(int i =0; i<INIT_CONNECTIONS;
 
i++) {
			try {
				Connection conn = DriverManager.getConnection(URL, USER, PASSWORD);//建立連線
				pool.addLast(conn);//將連線放進連線池
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}

	//獲取連線
	public Connection getConnect() {
		Connection result = null;
		lock.lock();
		try {
			while(pool.size
 
()<=0) {//如果連線池裡的連線小於等於0，就得讓獲取連線的執行緒等待
				try {
					c1.await();//讓獲取連線的執行緒等待
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
			}
			if(!pool.isEmpty()) {//連線池不為空
				result = pool.removeFirst();//拿到第一個連線
			}
			return result;
		}finally {
			lock.unlock();
		}
	}
	//釋放連線
	public void release(Connection conn) {
		if(conn != null) {
			lock.lock();
			try {
				pool.addLast(conn);//將連線放回到連線池
				c1.signal();//叫醒獲取連線的執行緒
			}finally {
				lock.unlock();
			}
		}
	}
}