code: public Connection getConnection() throws IOException {
  		Connection conn = null;
  		if (this.datasource != null) {
  			try {
  				conn = this.datasource.getConnection();
  			} catch (SQLException e) {
  				throw new IOException(e);
  			}
  		}
  		return conn;
  	}
docs: 获取数据库连接
  
  @return 数据库连接