OJB中的多条件查询

文章作者 100test 发表时间 2007:03:14 16:46:51
来源 100Test.Com百考试题网

项目还是一样，以一个reservation为例，一个reservation就是一个课程在实际中的体现，它有开始和终止时间还有状态等信息。timeslot就是定义了他的时间，里面有三个字段(timeslotID,start,end,reservationID)。

1。我要查询课程，输入的参数是一个时间段，得到的是一个reservation的列表。我可以这样做

1. /*
2. * (non-Javadoc)
3. * @see org.pie.vls.Application.VLSBase#init()
4. */
5. public void init() {
6. try {
7. broker = PersistenceBrokerFactory.defaultPersistenceBroker().
8. broker.clearCache().
10. //general criteria, with all the query condition
11. Criteria crit = new Criteria().
12. Criteria crit1 = null.
13. List criteriaList = new Vector().
14. //if the reservation id is not 0
15. if (resvID > 0) {
16. crit.addNotEqualTo("resvID", new Integer(this.resvID)).
17. }
19. Iterator iter = this.reservationTimeslotList.iterator().
20. while (iter.hasNext()) {
21. //logger.debug ("TIMESLOT -----").
22. ReservationTimeslot reservationTimeslot = (ReservationTimeslot) iter.next().
23. /**
24. * set the query condition list
25. * start and end
26. */
27. startTimeUTC = reservationTimeslot.getStartDateTimeUTC().
28. endTimeUTC = reservationTimeslot.getEndDateTimeUTC().
29. if (this.0selectType == Constants.BETWEEN_RESERVATIONS) {
30. crit1 = new Criteria().
31. //logger.debug ("BETWEEN " startTimeUTC " " endTimeUTC).
32. crit1.addBetween("start", startTimeUTC, endTimeUTC).
33. Criteria critMore1 = new Criteria().
34. critMore1.addBetween("end", startTimeUTC, endTimeUTC).
35. Criteria critMore2 = new Criteria().
36. critMore2.addLessOrEqualThan("start", startTimeUTC).
37. critMore2.addGreaterOrEqualThan("end", endTimeUTC).
38. crit1.addOrCriteria(critMore1).
39. crit1.addOrCriteria(critMore2).
40. }
42. criteriaList.add(crit1.copy(true, true, true)).
43. }
45. if (criteriaList.size() > 0) {
46. crit1 = new Criteria().
47. for (int i = 0. i < criteriaList.size(). i ) {
48. crit1.addOrCriteria((Criteria) criteriaList.get(i)).
49. }
50. crit.addAndCriteria(crit1).
51. }
52. logger.debug(crit).
53. QueryByCriteria tquery = QueryFactory.newQuery(Timeslot.class, crit).
54. this.timeslots = broker.getCollectionByQuery(tquery).
55. broker.clearCache().
56. broker.close().
57. } catch (Throwable t) {
58. logger.error(t.getMessage(), t).
59. }
60. }

2. 如果我要创建一个reservation，要判断的是当前这个创建的reservation是否与其它的reservation有交叉点的时间，那查询条件就这样修改

1. broker = PersistenceBrokerFactory.defaultPersistenceBroker().
2. broker.clearCache().
3. //general criteria, with all the query condition
4. Criteria crit = new Criteria().
5. Criteria crit1 = null.
6. List criteriaList = new Vector().
7. if (this.0selectType == Constants.TOUCHING_RESERVATIONS) {
8. crit1 = new Criteria().
9. /**
10. *

    the start time is in between this.startTimeUTC and this.endTimeUTC

11. */
12. crit1.addGreaterOrEqualThan("start", startTimeUTC).
13. crit1.addLessOrEqualThan("start", endTimeUTC).
14. /**
15. *

    the end time is in between this.startTimeUTC and this.endTimeUTC

16. */
17. Criteria crit2 = new Criteria().
18. crit2.addGreaterOrEqualThan("end", startTimeUTC).
19. crit2.addLessOrEqualThan("end", endTimeUTC).
21. /**
22. *

    the start time is in less than this.startTimeUTC and

23. * the end time is greater than this.endTimeUTC
24. */
25. Criteria crit3 = new Criteria().
26. crit3.addLessOrEqualThan("start", startTimeUTC).
27. crit3.addGreaterOrEqualThan("end", endTimeUTC).
28. crit1.addOrCriteria(crit2).
29. crit1.addOrCriteria(crit3).
30. }
31. criteriaList.add(crit1.copy(true, true, true)).
32. if (criteriaList.size() > 0) {
33. crit1 = new Criteria().
34. for (int i = 0. i < criteriaList.size(). i ) {
35. crit1.addOrCriteria((Criteria) criteriaList.get(i)).
36. }
37. crit.addAndCriteria(crit1).
38. }
39. QueryByCriteria tquery = QueryFactory.newQuery(Timeslot.class, crit).
40. this.timeslots = broker.getCollectionByQuery(tquery).
41. broker.clearCache().
42. broker.close().