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Hibernate Session 获取connection

2024-07-10 21:39:59   225人阅读

Hibernate Session 获取connection

由于最近一个项目要用到一条辅助的SQL ,hibernate里面的SQLQuery API 总的SQL语句不能包含 : 冒号, 固放弃Hibernate, 直接使用JDBC.

Hibernate3.3.2版本中getSession().connection()已被弃用，替代方法

SessionFactoryUtils.getDataSource(getSessionFactory()).getConnection()

原有方法

getSession().connection()

 

来自类org.springframework.orm.hibernate3.SessionFactoryUtils

例子：

      

  java.sql.Connection c = null;        java.sql.PreparedStatement ps = null;        java.sql.ResultSet rs = null;public List method(String sql) {        List ret = new ArrayList();        try {        c = SessionFactoryUtils.getDataSource(getSessionFactory()).getConnection();            ps = c.prepareStatement(sql);            rs = ps.executeQuery();            while(rs.next()) {                 .....                }                ret.add(ro);            }        } catch (Exception e) {             e.printStackTrace();       } finally {           close();        }        return ret;    }

 

我的demo

/**     *      *      * @author mjorcen     * @email mjorcen@gmail.com     * @dateTime Jul 4, 2014 5:43:05 PM     * @version 1     * @throws SQLException     */    private void getTop() throws SQLException {        StringBuilder sb = new StringBuilder();        sb.append("SELECT X.COMMENT_ID, X.TOTAL_NO, X.ORDER_NO, IFNULL(X.ORDER_NO / X.TOTAL_NO, 1) AS PERCENTAGE_NO  ");        sb.append("FROM (SELECT @rowNum := @rowNum + 1 AS ORDER_NO, @rowCount AS TOTAL_NO, t.COMMENT_ID, t.COMMENT_SPENDING  ");        sb.append("    FROM T_SD_COMMENT t, (SELECT @rowNum := 0  ");        sb.append("        ) b, (SELECT @rowCount := (  ");        sb.append("                SELECT COUNT(*)  ");        sb.append("                FROM T_SD_COMMENT  ");        sb.append("                WHERE to_days(CREATE_TIME) >= to_days(now())  ");        sb.append("                )  ");        sb.append("        ) c  ");        sb.append("     WHERE to_days(t.CREATE_TIME) >= to_days(now()) ORDER BY t.COMMENT_SPENDING ,t.COMMENT_ID ");        sb.append("    ) X  ");        sb.append("WHERE X.COMMENT_ID = ?  ");        Connection c = this.commentService.getSession().connection();        PreparedStatement ps = c.prepareStatement(sb.toString());        ps.setInt(1, this.paramComment.getCommentId());        ResultSet rs = ps.executeQuery();        if (rs.next()) {            System.out.println("COMMENT_ID = " + rs.getInt("COMMENT_ID"));            System.out.println("TOTAL_NO = " + rs.getInt("TOTAL_NO"));            System.out.println("ORDER_NO = " + rs.getInt("ORDER_NO"));            System.out.println("PERCENTAGE_NO = " + rs.getDouble("PERCENTAGE_NO"));        }    }

 

Hibernate API中让使用doWork(Work,work)，描述如下：

connection() 
          Deprecated. (scheduled for removal in 4.x). Replacement depends on need; for doing direct JDBC stuff use doWork(org.hibernate.jdbc.Work); for opening a ‘temporary Session‘ use (TBD).

 

Work接口的execute()方法用于执行直接通过JDBC API来访问数据库的操作：

public interface Work {    // 直接通过JDBC API来访问数据库的操作    public void execute(Connection connection) throws SQLException;}

 Session的doWork(Work  work)方法用于执行Work对象指定的操作，即调用Work对象的execute()方法。

 Session会把当前使用的数据库连接传给execute()方法。

 过程如下：

Transaction tx = session.beginTransaction();    // 定义一个匿名类，实现了Work接口    Work work = new Work() {        public void execute(Connection connection) throws SQLException {            // 通过JDBC API执行用于批量更新的SQL语句            PreparedStatement stmt = connection                    .prepareStatement("update CUSTOMERS set AGE=AGE+1 "                            + "where AGE>0 ");            stmt.executeUpdate();        }    };

执行work

session.doWork(work);tx.commit();

当通过JDBC API中的PreparedStatement接口来执行SQL语句时，SQL语句中涉及到的数据不会被加载到Session的缓存中，因此不会占用内存空间。

 

 

 

 

 

 


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