Question

希望这是一个非常简单的问题。如何将类传递给抽象方法？

我的抽象方法如下：

public abstract class IDataList {

    public LinkedList<IThing> getRows(IThing thing, String sql, List<Object> vals) throws Exception {
        LinkedList<IThing> list = new LinkedList<>();
        List<LinkedHashMap<String, Object>> rows = db.executeSelect(sql, vals);
        for (HashMap<String, Object> row : rows) {
            list.add(new thing(row));
        }
        rowCount = (long) getDb().executeScalar("SELECT FOUND_ROWS()");
        return list;
    }
}

由具体类继承：

public class DataList extends IDataList {

}

IThing目前是一个空的抽象类，它由Thing扩展，例如：

public class Thing extends IThing {

    private long uid;
    private String name;

    public Thing(HashMap<String, Object> row) {
        this.uid = (long) row.get("uid");
        this.name = (String)row.get("name");
    }
}

我希望能够将Thing传递给具体的IDataList类，例如：

IDataList dataList = new DataList();
dataList.getRows(Thing, "select something", new ArrayList<>())

Answer 1

如果您想将Thing类用作Row-＆gt; Object mapper，最好使用org.springframework.jdbc.core.RowMapper

public class CustomerRowMapper implements RowMapper {
    public Object mapRow(ResultSet rs, int rowNum) throws SQLException {
        Customer customer = new Customer();
        customer.setCustId(rs.getInt("CUST_ID"));
        customer.setName(rs.getString("NAME"));
        customer.setAge(rs.getInt("AGE"));
        return customer;
    }

}

public Customer findByCustomerId(int custId) {
    String sql = "SELECT * FROM CUSTOMER WHERE CUST_ID = ?";
    Customer customer = (Customer)getJdbcTemplate().queryForObject(sql, new Object[] { custId }, new CustomerRowMapper());
    return customer;
}

动态传递一个类

1 个答案: