使用Restrictions.between（）生成一个where子句，该子句的日期列在‘2012-04-09
00:00:00’和‘2012-04-09 23:59:59’之间

SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
Date fromDate = df.parse("2012-04-09 00:00:00");
Date toDate = df.parse("2012-04-09 23:59:59");

criteria.add(Restrictions.between("dateField", fromDate, toDate));

请注意，Criteria API中使用的所有属性都是Java属性名，而不是实际的列名。

更新：仅使用JDK获取当前日期的fromDate和toDate

Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY, 0);
calendar.set(Calendar.MINUTE, 0);
calendar.set(Calendar.SECOND, 0);
Date fromDate = calendar.getTime();

calendar.set(Calendar.HOUR_OF_DAY, 23);
calendar.set(Calendar.MINUTE, 59);
calendar.set(Calendar.SECOND, 59);
Date toDate = calendar.getTime();

criteria.add(Restrictions.between("dateField", fromDate, toDate));