public TJb checkjbByschool(long id)throws ClassNotFoundException,SQLException { Class.forName("com.mysql.jdbc.Driver"); Connection connection = DriverManager.getConnection("jdbc:mysql://127.0.0.1/sql", "user1", "11111111"); Statement statement = connection.createStatement(); ResultSet resultSet; String s = "select * from tjb " + "where time=(select max(time) from tjb where school ="+school_id+" ) " + "and school="+school_id; resultSet = statement.executeQuery(s); if (resultSet.next()) { TJb jb = (TJb)jbRepository.findOne(resultSet.getLong("id")); /**数据库关闭链接**/ connection.close(); return jb; } else { /**数据库关闭链接**/ connection.close(); return null; } }