Hibernate3 提供了DetachedCriteria,使得我们可以在Web层构造 @9P9U`ZP
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detachedCriteria,然后调用业务层Bean,进行动态条件查询,根 >bP7}T
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据这一功能,我设计了通用的抽象Bean基类和分页类支持,代码来 QF6JZQh<
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自于Quake Wang的javaeye-core包的相应类,然后又做了很多修改 p"
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分页支持类: g5N<B+?!i
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java代码: ,colGth54
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package com.javaeye.common.util; H LGy"P
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import java.util.List; *J5euA5=
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publicclass PaginationSupport { jmVy4* P_
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publicfinalstaticint PAGESIZE = 30; iz5wUyeg
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privateint pageSize = PAGESIZE; k(Xv&Zn
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privateList items; yp'>+cLa
AQU: 0
privateint totalCount; "lb!m9F{
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privateint[] indexes = newint[0]; ]Y!
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privateint startIndex = 0; 8ngf(#_{_n
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public PaginationSupport(List items, int 4?uG> ;V
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totalCount){ [`dipLkr
setPageSize(PAGESIZE); _qNLy/AY
setTotalCount(totalCount); '0rwNEg
setItems(items); -{mq\GvGn
setStartIndex(0); Tz~ftf
} +>({pHZ<S
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public PaginationSupport(List items, int X}^gmu<Vla
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totalCount, int startIndex){ XmR5dLc8
setPageSize(PAGESIZE); <OB~60h"
setTotalCount(totalCount); <cjTn:w
setItems(items); f_Bf}2Eedj
setStartIndex(startIndex); e:occT
} "A3xX&9-q
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public PaginationSupport(List items, int 1OS3Gv8jc~
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totalCount, int pageSize, int startIndex){ %W@IB8]Vr
setPageSize(pageSize); ( "z;Q?(
setTotalCount(totalCount); j)*nE./3
setItems(items); YJsi5
setStartIndex(startIndex); >*CK@"o
} pSUp"wch
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publicList getItems(){ 63$m& ]x
return items; NQ=YTRU
} NDGBvb
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publicvoid setItems(List items){ E+ 20->
this.items = items; rNp#5[e
} Xpwom'
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publicint getPageSize(){ 2wvDC@
return pageSize; eQj/)@B:V
} &i RX-)^u
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publicvoid setPageSize(int pageSize){ t,nB`g?
this.pageSize = pageSize; xc?<:h"
} rfpxE>_|G
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publicint getTotalCount(){ 2_v>8B
return totalCount; =Y[Ae7e
} :LG%8Z{R
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publicvoid setTotalCount(int totalCount){ \>k+Oyj
if(totalCount > 0){ X.<R['U&\
this.totalCount = totalCount; "-%H</
int count = totalCount / v^'~-^s
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pageSize; nrBitu,
if(totalCount % pageSize > 0) <X*8Xzmv
count++; -}o;Y)
indexes = newint[count]; _#B/#^a
for(int i = 0; i < count; i++){ eH{ 9w8~
indexes = pageSize * 6Tnzg`0I
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i; Ea?.HRxl
} AF6'JxG7
}else{ ba13^;fm#
this.totalCount = 0; H=C;g)R
} P+h&tXZn8
} 67?5Cv
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publicint[] getIndexes(){ H;1}Nvvd
return indexes; ;\N*iN#K
} M5uN1*
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publicvoid setIndexes(int[] indexes){ oDa{HP\O]W
this.indexes = indexes; TZg7BLfy
} _!7o
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publicint getStartIndex(){ (i8t^
return startIndex; %3j5Q
} )VC) }
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publicvoid setStartIndex(int startIndex){ T^_9R;
if(totalCount <= 0) D2bUSRrb
this.startIndex = 0; .&y1gh!=
elseif(startIndex >= totalCount) X[<9+Q-&
this.startIndex = indexes at!?"u
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[indexes.length - 1]; )w-?|2-w5
elseif(startIndex < 0) CCV~nf
this.startIndex = 0; Rd)QVEk>SD
else{ UZ#2*PH2E
this.startIndex = indexes >YLm]7v}
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[startIndex / pageSize]; g%trGW3{-
} 3QpTO,
} tS$Ne7yk e
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publicint getNextIndex(){ L@XeAEIq
int nextIndex = getStartIndex() + e=2D^G#qE
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pageSize; ]_s]Q_+E
if(nextIndex >= totalCount) sXu]k#I^"
return getStartIndex(); lS^0*(Y
else @zbXG_J
return nextIndex; }8HLyK,4
} i7FEjjGtG
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publicint getPreviousIndex(){ \+xsJbEV
int previousIndex = getStartIndex() - 4"sP= C
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pageSize; D_Y;N3E/rS
if(previousIndex < 0) FWg7e3
return0; 9\F^\h{
else ry'(mM
return previousIndex; Lmb<)YY
} \IKr+wlN8
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} F~1R.r_Lu
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抽象业务类 5S1m&s5k
java代码: <CFur
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/** 'g#GUSXfj
* Created on 2005-7-12 {%
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*/ YdFC YSiS
package com.javaeye.common.business; z2V!u\It
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import java.io.Serializable; VI?[8@*Z
import java.util.List; "q$M\jK#V
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import org.hibernate.Criteria; nB.p}k
import org.hibernate.HibernateException; ]arP6iN+
import org.hibernate.Session; !duR7a
import org.hibernate.criterion.DetachedCriteria; AF@C9s
import org.hibernate.criterion.Projections; tVO x
import <~d N23)
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org.springframework.orm.hibernate3.HibernateCallback; wQ5__"D
import yC[}gHv
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org.springframework.orm.hibernate3.support.HibernateDaoS Nx99dr
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upport;
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import com.javaeye.common.util.PaginationSupport; "jSn`
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public abstract class AbstractManager extends 7$ 'ja
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HibernateDaoSupport { GB#7w82
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privateboolean cacheQueries = false; 8L:0Wp
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privateString queryCacheRegion; ?^dyQhb
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publicvoid setCacheQueries(boolean S7bSR?~L[
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cacheQueries){ v[m>;Ubg&
this.cacheQueries = cacheQueries; 4h|vd.t
} C<3An_Dy
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publicvoid setQueryCacheRegion(String ^#nAS2w7U
j'Fni4;
queryCacheRegion){ 'G&w[8mqY
this.queryCacheRegion = K&/W cuP&
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queryCacheRegion; t4h* re+
} uB\A8zC
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publicvoid save(finalObject entity){ 2n\EZ
getHibernateTemplate().save(entity); n'SnqJ&}
} $3So`8Bm[$
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publicvoid persist(finalObject entity){ u!O)\m-
getHibernateTemplate().save(entity); +:b|I'S
} r_QWt1K
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publicvoid update(finalObject entity){ q N>j2~
getHibernateTemplate().update(entity); *p"%cas
} %
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publicvoid delete(finalObject entity){ ;aSEv"iWX
getHibernateTemplate().delete(entity); K#>B'>A\
} gD-<^Q-
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publicObject load(finalClass entity, Ra/S46$
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finalSerializable id){ T!8,R{V]4
return getHibernateTemplate().load *cf#:5Nl
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(entity, id); p?5zwdX+`
} "_lSw3
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publicObject get(finalClass entity, "bJW yUb
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finalSerializable id){ 0y?bwxkc
return getHibernateTemplate().get 9Z}-%Z[,)
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(entity, id); LVX.s tN#p
} &U:;jlST9
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publicList findAll(finalClass entity){ \]zHM.E1
return getHibernateTemplate().find("from u-D%: lz85
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" + entity.getName()); 8/k*"^3
} 'Je;3"@
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publicList findByNamedQuery(finalString U2;_{n*g%
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namedQuery){ {$Qw]?Yv
return getHibernateTemplate W 5-=,t
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().findByNamedQuery(namedQuery); d4~!d>{n|c
} ZjWI~"]
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publicList findByNamedQuery(finalString query, up1kg>i%"
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finalObject parameter){ s~3"*,3@
return getHibernateTemplate {>9vm!<[*\
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().findByNamedQuery(query, parameter); ^)TZHc2a[
} Tv!zqx#E
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publicList findByNamedQuery(finalString query, fTMn
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finalObject[] parameters){ #V@[<S2
return getHibernateTemplate 4PR!OB
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().findByNamedQuery(query, parameters); m;'ebkq
} w=,bF$:fIW
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publicList find(finalString query){ 1GE[*$vuq
return getHibernateTemplate().find f<<1.4)oSV
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(query); bZLY#g7L"
} FG/1!8F
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publicList find(finalString query, finalObject uWkW T.>$
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parameter){ f["c,,[
return getHibernateTemplate().find ^?}-x
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(query, parameter); qx|~H'UuBN
} \(C6|-:GY
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public PaginationSupport findPageByCriteria ~6DaM!
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(final DetachedCriteria detachedCriteria){ \8g'v@$wG
return findPageByCriteria VX0}x+LJ
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(detachedCriteria, PaginationSupport.PAGESIZE, 0); Y'*oW+K
} FN\*x:g
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public PaginationSupport findPageByCriteria QWcQtM
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(final DetachedCriteria detachedCriteria, finalint l|v`B6(
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startIndex){ 0~4Ww=#
return findPageByCriteria #x*\dL
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(detachedCriteria, PaginationSupport.PAGESIZE, c^3,e/H
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startIndex); ||D PIn]
} ,+~8R"
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public PaginationSupport findPageByCriteria 5/8=Do](
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(final DetachedCriteria detachedCriteria, finalint R"W5R-
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pageSize, ]n}aePl}oU
finalint startIndex){ V_zU?}lZ^
return(PaginationSupport) j<'ftKk
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getHibernateTemplate().execute(new HibernateCallback(){ G>=Fdt7Oc
publicObject doInHibernate 9A~w2z\G
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(Session session)throws HibernateException { iYD5~pK8
Criteria criteria = sKCYGt$
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detachedCriteria.getExecutableCriteria(session); DG?g~{Y~b
int totalCount = t'1g+g
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((Integer) criteria.setProjection(Projections.rowCount
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()).uniqueResult()).intValue(); (@->AJF1\
criteria.setProjection I3HO><of
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(null); t W+"/<U
List items = \HXq~Y
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criteria.setFirstResult(startIndex).setMaxResults i-PK59VZ8f
"}MP {/
(pageSize).list(); q
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PaginationSupport ps = =p^$>o
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new PaginationSupport(items, totalCount, pageSize, ?Z2`8]-E
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startIndex); \3OEC`
return ps; Ge_fU'F
} Q3Pu<j}Y
}, true); @^T~W^+
} p#).;\M
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public List findAllByCriteria(final D=Q.Q
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DetachedCriteria detachedCriteria){ hr;^.a^
return(List) getHibernateTemplate ;plBo%EBV
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().execute(new HibernateCallback(){ 6R,Y.srR
publicObject doInHibernate ( +Sv3h
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(Session session)throws HibernateException { D(l,Z
Criteria criteria = 6@TU9AZS`
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detachedCriteria.getExecutableCriteria(session); ]!ox2m_U
return criteria.list(); VwpC UW
} n&Ckfo_D
}, true); f`:GjA,J$
} - w*fS,O
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public int getCountByCriteria(final C7ug\_,s
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DetachedCriteria detachedCriteria){ ~5'7u-;
Integer count = (Integer) s3eS` rK-
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getHibernateTemplate().execute(new HibernateCallback(){ Lo3N)~5
publicObject doInHibernate /cb`%"Z
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(Session session)throws HibernateException { y{/7z}d
Criteria criteria = 9wZ?")2
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detachedCriteria.getExecutableCriteria(session); _tJt
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return ] L97k(:Ib
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criteria.setProjection(Projections.rowCount TKM^
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()).uniqueResult(); E{EO9EI
} Z/%FQ
}, true); kV+^1@"
return count.intValue(); Wk\(jaL%
} GA[Ebzi
} ydy TDn
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用户在web层构造查询条件detachedCriteria,和可选的 y QClq{A
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startIndex,调用业务bean的相应findByCriteria方法,返回一个 z3y{0<3
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PaginationSupport的实例ps。 *mzi ?3
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ps.getItems()得到已分页好的结果集 TY)QE
ps.getIndexes()得到分页索引的数组 i}VF$XN
ps.getTotalCount()得到总结果数 SK
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ps.getStartIndex()当前分页索引 T[Zs{S
ps.getNextIndex()下一页索引 HwHF8#D*l
ps.getPreviousIndex()上一页索引 O;~e^ <*
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连续看了两篇robbin有关DetachedCriteria的介绍,感觉真的不错 l)9IgJ|<b
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,尤其是上面的示例代码,让我着实觉得该对我原来的分页查询做 B W<Dmn
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一下代码重构了。 se\f be ^0
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我把原本我的做法也提供出来供大家讨论吧: N[po)}hp
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首先,为了实现分页查询,我封装了一个Page类: [3jJQ3O,
java代码: F{0\a;U@^
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/*Created on 2005-4-14*/ <{isWEW9]3
package org.flyware.util.page; I.n,TJoz4J
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/** BM<q;;pO
* @author Joa 9B!Sv/)y!r
* mux/\TII
*/ QWk3y"5n<
publicclass Page { UDHWl_%L
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/** imply if the page has previous page */ e0TYHr)X>3
privateboolean hasPrePage; }:0_%=)N<
M76p=*
/** imply if the page has next page */ CIx(SeEF
privateboolean hasNextPage; 'OsZD?W{
2aj1IBnz6/
/** the number of every page */ /W/e%.
privateint everyPage; uzBQK
; ~pgF_
/** the total page number */ M]s\F(*ib
privateint totalPage; +/ZIs|B4,z
i>YS%&O?
/** the number of current page */ F_Y]>,U
privateint currentPage; /'sv7hg+
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/** the begin index of the records by the current 3YHEH\60^
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query */ suY47DCX)
privateint beginIndex; zMsup4cl
T Rv
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/** The default constructor */ 0$*7lQ<a#M
public Page(){ 8K,X3a9
h p]J>i.
} >Zb!?ntN`t
aV\i3\da
/** construct the page by everyPage Vu3DP+u|i
* @param everyPage 5(+9a
* */ Xs~'M/>
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public Page(int everyPage){ GbSCk}>
this.everyPage = everyPage; P8eCaZg?(3
} C[L 5H
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/** The whole constructor */ <Ht"t]u*Bn
public Page(boolean hasPrePage, boolean hasNextPage,
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2_q/<8t
int everyPage, int totalPage, %e~xO x
int currentPage, int beginIndex){ {<42PJtPY
this.hasPrePage = hasPrePage; d4| )=
this.hasNextPage = hasNextPage; /j~~S'sw
this.everyPage = everyPage; AY /9Io-
this.totalPage = totalPage; 2][9Wp
this.currentPage = currentPage; danPy2
this.beginIndex = beginIndex; rtj/&>
} 39v Bsc
t7f(%/] H0
/** > Vm}u`x
* @return "wgPPop
* Returns the beginIndex. M+ +Dk7B
*/ EtcT:k?y
publicint getBeginIndex(){ q3x"9i
`
return beginIndex; \u,CixV=
} Db|f"3rq?
ZC?~RXL(
/** 3"h*L8No
* @param beginIndex o(hUC$vW
* The beginIndex to set. o%_-u
+
*/ \lbH
publicvoid setBeginIndex(int beginIndex){ @Tu`0=8
this.beginIndex = beginIndex; tx09B)0
} Qc7*p]E&
[+\He/M6
/** 2j-l<!s
* @return A%^?z.
* Returns the currentPage. ctP+ECH
*/ n9Fq^^?
publicint getCurrentPage(){ evyjHc Cx
return currentPage; RN`TUCQL
} Xh8U}w<k6
So ziFI
/** G<C D4:V
* @param currentPage #:?:gY<
* The currentPage to set. BZ?w}%-MO
*/ JN8Rh
publicvoid setCurrentPage(int currentPage){ tj;47UtH
this.currentPage = currentPage; y4kn2Mw;
} 7J);{ &x9h
<Y`(J#
/** k6#$Nb606
* @return e|tx`yA
* Returns the everyPage. 7m#EqF$P
*/ 1)~|{X+~
publicint getEveryPage(){ O C&BJNOi
return everyPage; x// uF
} W>TG?hH
e)}E&D;${
/** [A~?V.G
* @param everyPage #._JB-,'
* The everyPage to set. _WS8I>
*/ v.RA{a 9
publicvoid setEveryPage(int everyPage){ -|V#U`mwF
this.everyPage = everyPage; oXZWg~&l^
} PJK:LZw
KH2]:&6:Q
/** 6w%n$tiX
* @return z?DCQ
* Returns the hasNextPage. yy5|8L
*/ Xm,fyk>
publicboolean getHasNextPage(){ g[~{iu_$d
return hasNextPage; y(DT^>0
} CzlG#?kU?2
&<><4MQ
/** a<-aE4wdm
* @param hasNextPage NnAIL;WS
* The hasNextPage to set. )xVf3l
pQ
*/ jGouwta
publicvoid setHasNextPage(boolean hasNextPage){ Jj)J5S /
this.hasNextPage = hasNextPage; :i{M1z I
} |OLXb+7X
r`-8+"P
/** T'6`A<`3
* @return ]\rQ{No
* Returns the hasPrePage. ]EK(k7nH
*/ .c>6}:ye
publicboolean getHasPrePage(){ 9 m8KDB[N
return hasPrePage; * K$U[$s
} *-ys}sX
T @^ S:K
/** %f<>Kwr`2
* @param hasPrePage 2=?3MXcjy
* The hasPrePage to set. fln[Q2zl
*/ `Ij EwKra
publicvoid setHasPrePage(boolean hasPrePage){ *SJ[~
this.hasPrePage = hasPrePage; B9,39rG/7+
} jwjLxt
j3&q?1
/** "$N$:B @U
* @return Returns the totalPage. jOCV)V9}
* -"zW"v)\
*/ ;'Hu75ymo
publicint getTotalPage(){ r\QV%09R
return totalPage; %KVmpWku
} ]-t>F
b~UWFX#U
/** kB?/_a`]
* @param totalPage 1>[#./@
* The totalPage to set. Ep(xlHTv
*/ mxEe
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publicvoid setTotalPage(int totalPage){ .<vXj QE
this.totalPage = totalPage; P84YriLo
} vJs6nVbK
rV\G/)xL
} Pek[j)g}
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上面的这个Page类对象只是一个完整的Page描述,接下来我写了一 xyo~p,(~t
#8L:.,AYE
个PageUtil,负责对Page对象进行构造: lV:feX
java代码: !e<5JO;c
v6G1y[Wl
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/*Created on 2005-4-14*/ NL:dyV}
package org.flyware.util.page; &*o4~6pQ#
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import org.apache.commons.logging.Log; i+5Qs-dHA
import org.apache.commons.logging.LogFactory; kIa16m
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/** _1RvK? ;.{
* @author Joa E5A"sB
* gJp6ReZ#
*/ O`Qke
Z}
publicclass PageUtil { T*@o?U
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privatestaticfinal Log logger = LogFactory.getLog _R|_1xa=
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(PageUtil.class); sMAj?]hI$
Q7e4MKy7
/**
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* Use the origin page to create a new page n CwA8AG
* @param page 74N_> 1!j
* @param totalRecords ?7pn%_S
* @return > dVhIbG
*/ ~-NSIV:f
publicstatic Page createPage(Page page, int w:nH_x#C4
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totalRecords){ L8n?F#q
return createPage(page.getEveryPage(), @r[SqGa:
mW {uChHP
page.getCurrentPage(), totalRecords); oj.J;[-
} G:1QXwq\j
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/** ae-tAA[1Y
* the basic page utils not including exception 5nBJj
)2wf D
handler "5dke^yk0
* @param everyPage CB-;Jqb
* @param currentPage m+8:_0x "
* @param totalRecords !"<rlB,J
* @return page \:@7)(p\;
*/ i`f!) 1
publicstatic Page createPage(int everyPage, int G6{'|CV
} D!tB
currentPage, int totalRecords){ .fqy[qrM
everyPage = getEveryPage(everyPage); L'a+1O1q&i
currentPage = getCurrentPage(currentPage); IhK
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int beginIndex = getBeginIndex(everyPage, h}'Hst
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currentPage); $bKXP(
int totalPage = getTotalPage(everyPage, E@otV6Wk[@
{S+?n[1r\
totalRecords); @D*PO-s9
boolean hasNextPage = hasNextPage(currentPage, ud(0}[
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totalPage); sZ&6g<8#y
boolean hasPrePage = hasPrePage(currentPage); ts(u7CJd
5m'AT]5Tn_
returnnew Page(hasPrePage, hasNextPage, d3\?:}o,
everyPage, totalPage, %^E7Iqc
currentPage, ceJ#>Rj
"9^b1UH<
beginIndex); \tvL<U"'
} bh5P98s
Wtw,YFT
privatestaticint getEveryPage(int everyPage){ 6wu`;>
return everyPage == 0 ? 10 : everyPage; >`&2]Wc)
} #?r|6<4X
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privatestaticint getCurrentPage(int currentPage){ xx1l Ecj
return currentPage == 0 ? 1 : currentPage; &QD)1b[U
} Z~h6^h
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privatestaticint getBeginIndex(int everyPage, int ]=ApYg7!
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currentPage){ 4x-,l1NMR
return(currentPage - 1) * everyPage; K%L6UQ;
} ^S;{;c+'
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privatestaticint getTotalPage(int everyPage, int *7Y#G8 s
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totalRecords){ p*g)-/mA
int totalPage = 0; un!v1g9O
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if(totalRecords % everyPage == 0) +\%]<YO
totalPage = totalRecords / everyPage;
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else 2G-"HOG
totalPage = totalRecords / everyPage + 1 ; VHqoa>U,*
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return totalPage; ct|0zl~
} {*n<A{$[
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privatestaticboolean hasPrePage(int currentPage){ B%u[gNZ
return currentPage == 1 ? false : true; \reVA$M[
} tboQn~&4
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privatestaticboolean hasNextPage(int currentPage, WvF{`N
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int totalPage){ ;*zLf 9i
return currentPage == totalPage || totalPage == 5*A5Y E-
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0 ? false : true; 5tkKd4VfL
} h]~FYY
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} R0#scr
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上面的这两个对象与具体的业务逻辑无关,可以独立和抽象。 }&7kT7ogO
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面对一个具体的业务逻辑:分页查询出User,每页10个结果。具体 Bi;a~qE
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做法如下: #l&*&R~>
1. 编写一个通用的结果存储类Result,这个类包含一个Page对象 03|nP$g
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的信息,和一个结果集List: s}Go")p<:
java代码: UMNNAX
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/*Created on 2005-6-13*/ z}-R^"40
package com.adt.bo; D}}?{pe
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import java.util.List; d)biMI}<5
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import org.flyware.util.page.Page; kk<%VKC
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/** '^WR5P<8c
* @author Joa (t5y$bc
*/ }yrs6pQ
publicclass Result { &