Question

sqlSession接口中有那些方法

Answer 1

在平时开发中hibernate提供的hql基本能够满足我们的日常需求。但是在有些特殊的情况下，还是需要使用原生的sql,并且希望sql查询出来的结果能够绑定到pojo上。

Hibernate中由SQLQuery对象提供对原生sql语句的支持，例如如下语句在查询分析器中编写好后可直接使用

Sql代码
-- 查询采集设备及正在执行的任务 --
select d.guidID as deviceId, d.strName as deviceName,
p.guidID as portId, p.strName as portName,
t.guidTaskID as taskId, t.strName as taskName, t.enumRunStatus as runStatus,
t.odtTaskStartDate as taskStartDate, t.odtTaskStopDate as taskStopDate
from ULCDevice as d
inner join ULCDevicePort as p on p.guidBelongDeviceID = d.guidID
left outer join ULCTaskInfo as t on t.guidRecordPortID = p.guidID and t.enumRunStatus = 2
where d.enumType = 3
order by d.guidID;

HibernateCallback中，使用Session创建SQLQuery对象:

Java代码
StringBuffer b = new StringBuffer();

//... 省略SQL拼接代码
String sql = b.toString();

SQLQuery query = session.createSQLQuery(sql);

最后的重点是如何将查询结果映射到pojo:
SQLQuery接口addScalar方法，可用于设置查询结果到Pojo的映射

SQLQuery addScalar(String columnAlias, Type type)
-- 参数中的Type为Hibernate中提供的数据库类型.

如何使用见如下代码：

Java代码
public List<WorkStations> getWorkStations() {
List<WorkStations> retList = this.getHibernateTemplate().executeFind(new HibernateCallback() {

@Override
public Object doInHibernate(Session session)
throws HibernateException, SQLException {

StringBuffer b = new StringBuffer()
.append("select d.guidID as deviceId, d.strName as deviceName, ")
.append("p.guidID as portId, p.strName as portName, ")
.append("t.guidTaskID as taskId, t.strName as taskName, t.enumRunStatus as runStatus, ")
.append("t.odtTaskStartDate as taskStartDate, t.odtTaskStopDate as taskStopDate ")
.append("from ULCDevice as d ")
.append("inner join ULCDevicePort as p on p.guidBelongDeviceID = d.guidID ")
.append("left outer join ULCTaskInfo as t on t.guidRecordPortID = p.guidID and t.enumRunStatus = 2 ")
.append("where d.enumType = 3 ")
.append("order by d.guidID");

String sql = b.toString();

SQLQuery query = session.createSQLQuery(sql);
query.addScalar("deviceId", Hibernate.STRING);
query.addScalar("deviceName", Hibernate.STRING);

query.addScalar("portId", Hibernate.STRING);
query.addScalar("portName", Hibernate.STRING);

query.addScalar("taskId", Hibernate.STRING);
query.addScalar("taskName", Hibernate.STRING);
query.addScalar("runStatus", Hibernate.INTEGER);

query.addScalar("taskStartDate", Hibernate.TIMESTAMP);
query.addScalar("taskStopDate", Hibernate.TIMESTAMP);

query.setResultTransformer(Transformers.aliasToBean(WorkStations.class));

List<WorkStations> list = query.list();
System.out.println(list.size());

return list;
}

});

return retList;
}

WorkStations.Java

Java代码
public class WorkStations implements Serializable {
private String deviceId = null;
private String deviceName = null;

private String portId = null;
private String portName = null;

private String taskId = null;
private String taskName = null;
private Integer runStatus = null;

private Date taskStartDate = null;
private Date taskStopDate = null;

public WorkStations() {

}

//... 省略 getter/sette r方法
}

Answer 2

你说的没错接口中确实不能有具体实现方法，但是我们可以让其他类继承这个接口来实现接口中定义的方法，建议初学者不要考虑这么多，知道怎么得到resultSet就可以了以及其方法的使用，其他的深点的东西工作后慢慢的研究吧