struts+spring+hibernate通用分页方法

分页有2种办法：

1、??? 从数据库中取得记录，在内存中再划分，如果遇到记录数很大的时候效率很成问题，此法不可取。

2、??? 采用hibernate的物理分页，每次只是取一页。从客户端传进来的是第几页和每页多少条记录，要首先查询符合记录的总记录数，再根据总记录数和当前页，每页记录数可以算出要取的是数据库中的第几条记录。2次查询不可避免了。

单元测试如下：
java 代码?
public?final?void?testFindAllRole()?{??
??
????????????logger.debug("testFindAllRole");??
??
????????????long?l1=System.currentTimeMillis();??
??
????????????String?myaction="roleList.do";??
??
????????????String?curPageNO?=?"1";??
??
????????????CriteriaQuery?cq=new?CriteriaQuery(Role.class,curPageNO,myaction);??
??
????????????cq.setPageSize(10);??
??
????????????PageSupport?ps=BeanFactory.getInstance().getRightDelegate().findAllRole(cq,?state);??
??
????????????long?l2=System.currentTimeMillis();??
??
????????????AppUtils.printCollection(ps.getResultList());????
??
????????????System.out.println("一共用时为?：??"+(l2-l1));????????????
??
????????}??

CriteriaQuery类是对hibernate QBC查询方法的封装，需要的参数是当前操作的实体类，myaction，curPageNO，pageSize，以便构造出相应的上下翻页的工具条。

在delegate中只是将值向下传：
java 代码?
public?PageSupport?findAllRole(CriteriaQuery?cq,?IState?state)?{??
??
????????if?(DelegateUtil.isNullParam(cq,?"CriteriaQuery",?state))?{??
??
????????????return?null;??
??
????????}??
??
????????Request?req?=?new?Request();??
??
????????req.setServiceName(ServiceConsts.FindAllRoleProcessor);??
??
????????req.setValue("CriteriaQuery",?cq);??
??
????????try?{??
??
????????????Response?resp?=?getDelegate().execute(req);??
??
????????????DelegateUtil.setIState(state,?resp);??
??
????????????return?(PageSupport)?(resp.getValue("PageSupport"));??
??
????????}?catch?(Exception?e)?{??
??
????????????DelegateUtil.handleException(e,?"findAllRole",?state);??
??
????????}??
??
????????return?new?PageSupport();??
??
????}? 

在业务逻辑模块command中:

java 代码?

1. public?class?FindAllRole?extends?Command??
2. {??
3. ????private?RoleDao?dao;??
4. ????public?void?setDao(RoleDao?dao)?{??
5. ????????this.dao?=?dao;??
6. ????}??
7. ????public?void?execute(Map?params,?Map?response)?throws?Exception??
8. ??
9. ????{??
10. ????????response.put("PageSupport",?(PageSupport)dao.find((CriteriaQuery)?params.get("CriteriaQuery"),true));??
11. ????}??
12. ……??
13. ??
14. }??

直接就是调用dao的find方法：

?? java 代码?
public?PageSupport?find(final?CriteriaQuery?cq,final?boolean?isOffset)?{??
???????return?(PageSupport)getHibernateTemplate().execute(??
???????????????new?HibernateCallback()?{??
???????????????????public?Object?doInHibernate(Session?session)?throws?HibernateException,?SQLException?{??
???????????????????????Criteria?criteria?=?cq.getDetachedCriteria().getExecutableCriteria(session);???
???????????????????????//得到总行数??
???????????????????????int?allCounts?=?((Integer)?criteria.setProjection(Projections.rowCount()).uniqueResult()).intValue();???
???????????????????????criteria.setProjection(null);//还原????
???????????????????????int?curPageNO?=?PagerUtil.getCurPageNO(cq.getCurPage());//?当前页??
???????????????????????int?offset?=?PagerUtil.getOffset(allCounts,?curPageNO,?cq.getPageSize());??
???????????????????????String?toolBar?=?PagerUtil.getBar(cq.getMyaction(),allCounts,curPageNO,cq.getPageSize());??
??
???????????????????????if(isOffset){??
??
???????????????????????????criteria.setFirstResult(offset);??
??
???????????????????????????criteria.setMaxResults(cq.getPageSize());??
??
???????????????????????}??
???????????????????????return?new?PageSupport(criteria.list(),toolBar,offset,curPageNO);??
??
???????????????????????????}??
?????????????????????}??
??
???????????????,true);??
???}??

在后台的整个操作中非常简练，只需要将带上参数的CriteriaQuery传到dao就可以实现。CriteriaQuery封装了hibernate的DetachedCriteria。

java 代码?

1. public?class?CriteriaQuery?implements?Serializable{??
2. ????public?CriteriaQuery(){??
3. ????????super();??
4. ????}??
5. ????private?static?final?long?serialVersionUID?=?-1464383406564081554L;??
6. ????//?初始化list??
7. ????private?String?curPage=null?;??
8. ????private?int?pageSize=10;??
9. ????private?String?myaction;??
10. ????private?String?myform;??
11. ????private?CriterionList?criterionList;??
12. ????private?DetachedCriteria?detachedCriteria;??
13. ??
14. ????public?CriteriaQuery(Class?c)?{??
15. ????????this.criterionList?=?new?CriterionList();??
16. ????????this.detachedCriteria=DetachedCriteria.forClass(c);??
17. ????}??
18. ????public?CriteriaQuery(Class?c,String?curPage,String?myaction,String?myform)?{??
19. ????????this.myaction=myaction;??
20. ????????this.myform=myform;??
21. ????????this.curPage=curPage;??
22. ????????this.criterionList?=?new?CriterionList();??
23. ????????this.detachedCriteria=DetachedCriteria.forClass(c);??
24. ????}??
25. ????public?CriteriaQuery(Class?c,String?curPage,String?myaction)?{??
26. ????????this.myaction=myaction;??
27. ????????this.curPage=curPage;??
28. ????????this.criterionList?=?new?CriterionList();??
29. ????????this.detachedCriteria=DetachedCriteria.forClass(c);??
30. ????}??
31. ????public?CriterionList?getCriterionList()?{??
32. ????????return?criterionList;??
33. ????}??
34. ????public?void?setCriterionList(CriterionList?criterionList)?{??
35. ????????this.criterionList?=?criterionList;??
36. ????}??
37. ??
38. ????public?String?getCurPage()?{??
39. ????????return?curPage;??
40. ????}??
41. ????public?void?setCurPage(String?curPage)?{??
42. ????????this.curPage?=?curPage;??
43. ????}??
44. ????public?DetachedCriteria?getDetachedCriteria()?{??
45. ????????return?detachedCriteria;??
46. ????}??
47. ????public?void?setDetachedCriteria(DetachedCriteria?detachedCriteria)?{??
48. ????????this.detachedCriteria?=?detachedCriteria;??
49. ????}??
50. ????public?void?add(Criterion?c)?{??
51. ????????????detachedCriteria.add(c);??
52. ????}??
53. ????public?void?add()?{??
54. ????????for(int?i=0;i
55. ????????????add(getCriterionList().getParas(i));??
56. ????????}??
57. ????}??
58. ????public?void?createAlias(String?name){??
59. ????????detachedCriteria.createCriteria(name);??
60. ????}??
61. ????public?void?createAlias(String?name,String?value){??
62. ????????detachedCriteria.createCriteria(name,value);??
63. ????}??
64. ????public?Criterion?and(CriteriaQuery?query,?int?source,?int?dest)?{??
65. ????????return?Restrictions.and(query.getCriterionList().getParas(source),query.getCriterionList().getParas(dest));??
66. ????}??
67. ????public?Criterion?and(Criterion?c,CriteriaQuery?query,?int?source)?{??
68. ????????return?Restrictions.and(c,?query.getCriterionList().getParas(source));??
69. ????}??
70. ????public?Criterion?and(Criterion?c1,?Criterion?c2)?{??
71. ????????return?Restrictions.and(c1,c2);??
72. ????}??
73. ????public?Criterion?or(CriteriaQuery?query,?int?source,?int?dest)?{??
74. ????????return?Restrictions.or(query.getCriterionList().getParas(source),query.getCriterionList().getParas(dest));??
75. ????}??
76. ??????
77. ????public?Criterion?or(Criterion?c,CriteriaQuery?query,?int?source)?{??
78. ????????return?Restrictions.or(c,?query.getCriterionList().getParas(source));??
79. ????}??
80. ??????
81. ????public?void?or(Criterion?c1,?Criterion?c2)?{??
82. ????????this.detachedCriteria.add(Restrictions.or(c1,c2));??
83. ????}??
84. ????public?void?addOrder(String?ordername,String?ordervalue)?{??
85. ????????//?写入order查询条件??
86. ????????if?("asc".equals(ordername))?{??
87. ????????????detachedCriteria.addOrder(Order.asc(ordervalue));??
88. ????????}?else?{??
89. ????????????detachedCriteria.addOrder(Order.desc(ordervalue));??
90. ????????}??
91. ????}??
92. ????public?void?eq(String?keyname,Object?keyvalue){??
93. ????????criterionList.addPara(Restrictions.eq(keyname,?keyvalue));??
94. ????}??
95. ????public?void?notEq(String?keyname,Object?keyvalue){??
96. ????????criterionList.addPara(Restrictions.or(Restrictions.gt(keyname,?keyvalue),Restrictions.lt(keyname,?keyvalue)));??
97. ????}??
98. ????public?void?like(String?keyname,Object?keyvalue){??
99. ????????criterionList.addPara(Restrictions.like(keyname,?keyvalue));??
100. ????}??
101. ????public?void?gt(String?keyname,Object?keyvalue){??
102. ????????criterionList.addPara(Restrictions.gt(keyname,?keyvalue));??
103. ????}??
104. ????public?void?lt(String?keyname,Object?keyvalue){??
105. ????????criterionList.addPara(Restrictions.lt(keyname,?keyvalue));??
106. ????}??
107. ????public?void?le(String?keyname,Object?keyvalue){??
108. ????????criterionList.addPara(Restrictions.le(keyname,?keyvalue));??
109. ????}??
110. ????public?void?ge(String?keyname,Object?keyvalue){??
111. ????????criterionList.addPara(Restrictions.ge(keyname,?keyvalue));??
112. ????}??
113. ????public?void?ilike(String?keyname,Object[]?keyvalue){??
114. ????????criterionList.addPara(Restrictions.in(keyname,?keyvalue));??
115. ????}??
116. ????public?void?between(String?keyname,Object?keyvalue1,Object?keyvalue2)?{??
117. ????????Criterion?c=null;//?写入between查询条件??
118. ????????if?(!AppUtils.isBlank(keyvalue1)?&&?!AppUtils.isBlank(keyvalue2))?{??
119. ????????????c=Restrictions.between(keyname,?keyvalue1,?keyvalue2);??
120. ????????}?else?if?(!AppUtils.isBlank(keyvalue1))?{??
121. ????????????c=Restrictions.ge(keyname,?keyvalue1);??
122. ????????}?else?if?(!AppUtils.isBlank(keyvalue2))?{??
123. ????????????c=Restrictions.le(keyname,?keyvalue2);??
124. ????????}??
125. ????????criterionList.add(c);??
126. ????}??
127. ????public?int?getPageSize()?{??
128. ????????return?pageSize;??
129. ????}??
130. ????public?void?setPageSize(int?pageSize)?{??
131. ????????this.pageSize?=?pageSize;??
132. ????}??
133. ????public?String?getMyaction()?{??
134. ????????return?myaction;??
135. ????}??
136. ????public?void?setMyaction(String?myaction)?{??
137. ????????this.myaction?=?myaction;??
138. ????}??
139. ????public?String?getMyform()?{??
140. ????????return?myform;??
141. ????}??
142. ????public?void?setMyform(String?myform)?{??
143. ????????this.myform?=?myform;??
144. ????}??
145. }?
     

另外需要一些辅助类的支持：

例如PageSupport? 封装了返回的数据和工具条。
java 代码?
public?class?PageSupport??implements?Serializable{??
????private?int?curPageNO;??
????private?int?offset;??
????private?String?toolBar;??
????private?List?resultList=null;??
??
????public?PageSupport()?{??
??
????}??
????public?PageSupport(List?resultList,String?toolBar,int?offset,int?curPageNO)?{??
????????this.curPageNO=curPageNO;??
????????this.offset=offset;??
????????this.toolBar=toolBar;??
????????this.resultList=resultList;??
????}??
????public?List?getResultList()?{??
????????return?resultList;??
????}??
??
????public?void?setResultList(List?resultList)?{??
????????this.resultList?=?resultList;??
????}??
??
????public?String?getToolBar()?{??
????????return?toolBar;??
????}? 

CriterionList封装了Hibernate的参数:

java 代码?

1. /**?
2. ?*?封装了ArrayList，装的是Criterion?
3. ?*/??
4. public?class?CriterionList?extends?ArrayList?{??
5. ????public?final?Criterion?getParas(final?int?index)?{??
6. ????????return?(Criterion)?super.get(index);??
7. ????}??
8. ????public?final?void?addPara(final?int?index,?final?Criterion?p)?{??
9. ????????super.add(index,?p);??
10. ????}??
11. ????public?final?void?addPara(final?Criterion?p)?{??
12. ????????super.add(p);??
13. ????}??
14. ????public?final?int?indexofPara(final?Criterion?p)?{??
15. ????????return?super.indexOf(p);??
16. ????}??
17. ????public?final?void?removePara(final?int?index)?{??
18. ????????super.remove(index);??
19. ????}??
20. }??

PagerUtil用于将客户端的页码和每页多少个记录算出应该取数据库中的记录的位置，再由hibernate构造出一个三层的sql语句。
java 代码?

1. public?class?PagerUtil?{??
2. ????/**?
3. ?????*??
4. ?????*?@param?allCounts?总记录数?
5. ?????*?@param?curPageNO??
6. ?????*?@param?pageSize??每页显示的记录数目?
7. ?????*?@return?
8. ?????*/??
9. ????public?static?String??getBar(String?action,String?form,int?allCounts,int?curPageNO,?int?pageSize){??
10. ????????Pager?pager?=?null;??
11. ????????????try?{??
12. ????????????????if?(curPageNO<1)?curPageNO=1;??
13. ????????????????if?(curPageNO>?(int)?Math.ceil((double)?allCounts?/?pageSize))???
14. ????????????????????curPageNO?=(int)?Math.ceil((double)?allCounts?/?pageSize);??
15. ????????????????//得到offset??
16. ????????????????int?offset?=?(curPageNO-1)*pageSize;//从第几条开始取值??
17. ?????????????????//生成工具条??
18. ?????????????????pager=new?Pager(allCounts,offset,pageSize);??
19. ?????????????????pager.setCurPageNO(curPageNO);//设置当前的页码??
20. ????????????}?catch?(Exception?e)?{??
21. ????????????????System.out.println("生成工具条出错!");??
22. ??????????}??
23. ?????????return?pager.getToolBar(action,form);??
24. ????}??
25. ??????
26. ????public?static?String??getBar(String?url,int?allCounts,int?curPageNO,?int?pageSize){??
27. ????????Pager?pager?=?null;??
28. ????????????try?{??
29. ????????????????if?(curPageNO<1)?curPageNO=1;??
30. ????????????????if?(curPageNO>?(int)?Math.ceil((double)?allCounts?/?pageSize))???
31. ????????????????????curPageNO?=(int)?Math.ceil((double)?allCounts?/?pageSize);??
32. ????????????????//得到offset??
33. ????????????????int?offset?=?(curPageNO-1)*pageSize;//从第几条开始取值??
34. ?????????????????//生成工具条??
35. ?????????????????pager=new?Pager(allCounts,offset,pageSize);??
36. ?????????????????pager.setCurPageNO(curPageNO);//设置当前的页码??
37. ????????????}?catch?(Exception?e)?{??
38. ????????????????System.out.println("生成工具条出错!");??
39. ??????????}??
40. ?????????return?pager.getToolBar(url);??
41. ????}??
42. ??????
43. ????public?static?int?getOffset(int?rowCounts,int?curPageNO,?int?pageSize){??
44. ????????int?offset=0;??
45. ????????????try?{??
46. ????????????????//得到第几页??
47. ????????????????if?(curPageNO<1)?curPageNO=1;??
48. ????????????????if?(curPageNO>?(int)?Math.ceil((double)?rowCounts?/?pageSize))???
49. ????????????????????curPageNO?=(int)?Math.ceil((double)?rowCounts?/?pageSize);??
50. ????????????????//得到offset??
51. ??????????????????offset?=?(curPageNO-1)*pageSize;??
52. ????????????}?catch?(Exception?e)?{??
53. ????????????????System.out.println("getOffset出错!");??
54. ????????????}????
55. ???????return?offset;??
56. ????}??
57. ??????
58. ????public?static?int?getCurPageNO(String?curPage){??
59. ????????????int?curPageNO;??
60. ?????????????if?(curPage==null||"".equals(curPage.trim()))?{??
61. ?????????????????curPageNO=1;//第一次处于第一页??
62. ??????????????}?else?{??
63. ??????????????????try?{??
64. ??????????????????????curPageNO?=?Integer.parseInt(curPage);//得到当前页??
65. ????????????????}?catch?(Exception?e)?{??
66. ????????????????????curPageNO=1;??
67. ????????????????}??
68. ??????????????}??
69. ?????????????return?curPageNO;??
70. ????????}??
71. }?
    
72. 未完，待续
    

1 楼 aaa 2007-06-22 不是代码rar包呀? 2 楼 onecan 2007-06-22 代码关联到其他的功能了，需要整理一下 3 楼 drinkjava 2007-06-22 提一个变态的需求，如果一个页面上同时有多处出现同样内容的分页，如何处理？
即页面A上同时包含 B,B,B,B,B 5个相同的模块，5个B的内容完全相同，但要保证每个B模块的分页完全独立。 4 楼 onecan 2007-06-23 每个工具条是跟返回的记录绑定到一个pagesupport类里面，通过辅助的类将客户端传进来的参数转换为数据库记录的位置，并且用这些参数来构造一个工具条。pagesupport里面就一个list和string类型的变量，list是返回的记录，string是工具条的html代码，2者是对应的。不同的分页对应到不同的记录和工具条。但是5个分页同时放在一个页面，要注意不要同时刷新了。 5 楼 rainytooo 2007-06-25 现在大家都有自己的分页方案了吧
6 楼 yongyuan.jiang 2007-06-25 简单的分页写了那么多行代码，看都没心情看。