JAVA写简单的数据库连接池

public class ConnecionPool {
    private int size;
    List<Connection> connections = new ArrayList<>();
    public ConnecionPool(int size){
        this.size=size;
        init();
    }
    public void init(){

        try {
            Class.forName("com.mysql.jdbc.Driver");
            while (size--!=0){

                connections.add(DriverManager.getConnection(jdbc:mysql://127.0.0.1:3306/d数据库名称, 用户名，密码)// );

            }
        }catch (Exception e){
            e.printStackTrace();
        }
    }
    public Connection getConnection(){
        try {//如果没有连接了，线程就等待
            while (connections.isEmpty()){
                this.wait();
            }
        }catch (Exception e){
            e.printStackTrace();
        }
        return connections.remove(0);
    }
    public void returnConntion(Connection connection){
        connections.add(connection);
        this.notifyAll();
    }
}