Hibernate3 提供了DetachedCriteria,使得我们可以在Web层构造 <lf692.3
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detachedCriteria,然后调用业务层Bean,进行动态条件查询,根 fOHbgnL>
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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 g&xj(SMj-$
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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 :
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。 )4=86>XJT
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分页支持类: E .Xp\Dm71
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java代码: $kTm"I
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package com.javaeye.common.util; SZ9Oz-?
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import java.util.List; *zrGrk:l
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publicclass PaginationSupport { ]|CcQ1#|H
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publicfinalstaticint PAGESIZE = 30; rwLKY.J]
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privateint pageSize = PAGESIZE; Qy" Jt ]O
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privateList items; agx8 *x
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privateint totalCount; s`bGW1#io
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privateint[] indexes = newint[0]; ;m7G8)I
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privateint startIndex = 0; iN
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public PaginationSupport(List items, int 8)1q,[:M
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totalCount){ 0* F` h
setPageSize(PAGESIZE); f
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setTotalCount(totalCount); E,Rj;?
setItems(items); UF!qp
setStartIndex(0); d*d:-f~q
} \nEMj,)
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public PaginationSupport(List items, int ]H !ru
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totalCount, int startIndex){ PG63{
setPageSize(PAGESIZE); c36p+6rJk=
setTotalCount(totalCount); 'z"vk
setItems(items); 9Y.(xp &vw
setStartIndex(startIndex); @\?ubF
} hE {";/}J
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public PaginationSupport(List items, int ?4R%z([X7
:1*E5pX0n
totalCount, int pageSize, int startIndex){ $VHIU1JjZ
setPageSize(pageSize); &RZO\ZT
setTotalCount(totalCount); ) 1AAL0F\B
setItems(items); F9j@KC(yg
setStartIndex(startIndex); GfELL`yz
} =6dAF"b)
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publicList getItems(){ }?,?2U,8:
return items; 1- s(v)cxh
} ^5E9p@d"J
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publicvoid setItems(List items){ (SRY(q
this.items = items; ~6i'V?>
} Q<V(#)*
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publicint getPageSize(){ Xb%Q%"?~
return pageSize; AaYH(2m-
} !ddyJJ^a
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publicvoid setPageSize(int pageSize){ N4ZV+
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this.pageSize = pageSize; ({j8|{)+
} ?2&= +QaT
~-zIB=TyK
publicint getTotalCount(){ ,N(Yjq"R
return totalCount; nnj<k5
} H7tviSTd
jvB[bS`<H
publicvoid setTotalCount(int totalCount){ U)8yd,qG[%
if(totalCount > 0){ .m]}Ba}J$
this.totalCount = totalCount; pZ>yBY?R8>
int count = totalCount / [o<hQ`&
v>wN
O
pageSize; q|<B9Jk
if(totalCount % pageSize > 0) }8 z:L<
count++; 'w=|uE {^
indexes = newint[count]; !0@4*>n
for(int i = 0; i < count; i++){ o9e8Oj&
indexes = pageSize * T9V=#+8#"
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i; E_=F'sP?
} $97O7j@
}else{ vT EqT
this.totalCount = 0; '{2]:
} S#M8}+ZD,
} ,)[9RgsE
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publicint[] getIndexes(){ U&#`
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return indexes; VP
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} 9\.0v{&v
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publicvoid setIndexes(int[] indexes){ ? #rXc%F
this.indexes = indexes; Ge`7`D>L
} jlP*RX
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publicint getStartIndex(){ L4Jm8sy{
return startIndex; jcqUY+T$
} 'UsR/h5T
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publicvoid setStartIndex(int startIndex){ ^nPy(Q0
if(totalCount <= 0) O(W"QY
this.startIndex = 0; Nb$0pc1J<
elseif(startIndex >= totalCount) UAF$bR
this.startIndex = indexes #S?^?3d
%8n<#0v-|4
[indexes.length - 1]; u*@R`,Y
elseif(startIndex < 0) ! :]_-DX
this.startIndex = 0; #$BFTlm|
else{ }eVDe(7_
this.startIndex = indexes 3tf_\E+mIi
^!S4?<v
[startIndex / pageSize]; B9NUafK=
} X6
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} sR9$=91`
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publicint getNextIndex(){ ,CyX*k8o
int nextIndex = getStartIndex() + &'/"=lK
}9\_s*
pageSize; mvjx
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if(nextIndex >= totalCount) nKGQU,C
return getStartIndex(); 9Do75S{(
else $^fF}y6N
return nextIndex; 1TQ?Fxj
} Xq$-&~
@ !")shc
publicint getPreviousIndex(){ 4JK6<Pk
int previousIndex = getStartIndex() - nCi
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hOB<6Tm[
pageSize; n'mrLZw
if(previousIndex < 0) SEI0G_wk$
return0; fsjLD|?|:
else i[KXkjr
return previousIndex; Fl.?*KBz
} V|
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} q.=Q
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抽象业务类 /}@F
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java代码: zY\u"
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/** : 2%eh
* Created on 2005-7-12 :(XyiF<Ud
*/ TQO|C?
package com.javaeye.common.business; G@DNV3Cc
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import java.io.Serializable; FBl,Mky
import java.util.List;
{ 8 K
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import org.hibernate.Criteria; #Q=73~
import org.hibernate.HibernateException; OT\D;Z"__I
import org.hibernate.Session; ynA_Z^j
import org.hibernate.criterion.DetachedCriteria; c{Z
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import org.hibernate.criterion.Projections; 0\!Bh^++1
import i{EQjZ
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org.springframework.orm.hibernate3.HibernateCallback; q*lk9{>
import P\Qvj7_
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org.springframework.orm.hibernate3.support.HibernateDaoS "&SE!3*m`I
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upport; AT
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import com.javaeye.common.util.PaginationSupport; q}Po)IUT`5
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public abstract class AbstractManager extends
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HibernateDaoSupport { fwt+$`n
)*}\fmOv{
privateboolean cacheQueries = false; 0Lj;t/mG
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privateString queryCacheRegion; (QIU 3EN
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publicvoid setCacheQueries(boolean 10zM8<bl
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cacheQueries){ 8*8Y\"
this.cacheQueries = cacheQueries; e/Z{{FP%6
} 6?}|@y^fb
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publicvoid setQueryCacheRegion(String 1.p?1"4\u
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queryCacheRegion){ m>Wt'Cc
this.queryCacheRegion = B>E4,"
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queryCacheRegion; 4wKCzPy
} Fb<'L5}i
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publicvoid save(finalObject entity){ &kdW(;`
getHibernateTemplate().save(entity); S".|j$
} <P1nfH
0* x?rO?
publicvoid persist(finalObject entity){ pqs!kSJV
getHibernateTemplate().save(entity); 0UpRSh)#
} +>1Yp"> ?
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publicvoid update(finalObject entity){ 2Ax(q&`9
getHibernateTemplate().update(entity); dKPXs-5
} "8a
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publicvoid delete(finalObject entity){ ]z7pa^
getHibernateTemplate().delete(entity); 0o 7o;eN
} -U>)B
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publicObject load(finalClass entity, Z-t qSw8n
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finalSerializable id){ kxe{HxM$Z
return getHibernateTemplate().load $Rze[3
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(entity, id); A\ mSS
} SKf;Fe
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publicObject get(finalClass entity, L7 FFa:#
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finalSerializable id){ zLr:zf l
return getHibernateTemplate().get ~yN>9f U
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(entity, id); HHyN\
} <AVWT+,
}6u}?>S
publicList findAll(finalClass entity){ 'GW~~UhdW
return getHibernateTemplate().find("from _Hq)@AI
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" + entity.getName()); 7KC2%s#7
} CiU^U|~ 'L
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publicList findByNamedQuery(finalString %A
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namedQuery){ @pvQci
return getHibernateTemplate y1Br4K5C
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().findByNamedQuery(namedQuery); I&8!V)r)
} Wf:X)S7
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publicList findByNamedQuery(finalString query, siuDg,uqK5
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finalObject parameter){ <!W9EM
return getHibernateTemplate
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]$)};8;7W
().findByNamedQuery(query, parameter); 1iqgTi>
} Ktuv
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publicList findByNamedQuery(finalString query, _NuHz
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finalObject[] parameters){ R,!aX"]|
return getHibernateTemplate (Gzq 1+B
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().findByNamedQuery(query, parameters); gvjy'Rm
} >0N$R|B&
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publicList find(finalString query){ F ww S[3
return getHibernateTemplate().find J=t}N+:F`b
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(query); kU)E-h
} Ov:U3P?%
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publicList find(finalString query, finalObject /#x0?d{5
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parameter){ )1 0aDTlr
return getHibernateTemplate().find QSYKYgxC
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(query, parameter); pkIJbI{aS
} (:#4{C
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public PaginationSupport findPageByCriteria on\ahk, y]
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(final DetachedCriteria detachedCriteria){ <UwA5X`0e.
return findPageByCriteria *q1sM#;5
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(detachedCriteria, PaginationSupport.PAGESIZE, 0); d$D3iv^hyx
} yrMakT =
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public PaginationSupport findPageByCriteria :=`N2D
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(final DetachedCriteria detachedCriteria, finalint hG/Z65`&
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startIndex){ dBL{Mbh2Z
return findPageByCriteria `Z#]lS?
pKL^<'w0
(detachedCriteria, PaginationSupport.PAGESIZE, iaaD1<m
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startIndex); {M0pq3SL*t
} uc;,JX!bN
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public PaginationSupport findPageByCriteria rI]n4>k{
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(final DetachedCriteria detachedCriteria, finalint "OKsl2e
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pageSize, ;fY)7
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finalint startIndex){ 74Il]i1=
return(PaginationSupport) 8+~|!)a
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getHibernateTemplate().execute(new HibernateCallback(){ x6~`{N1N
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publicObject doInHibernate %$(*.o!+8
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(Session session)throws HibernateException { k@C]~1
Criteria criteria = gl6 *bB=
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detachedCriteria.getExecutableCriteria(session); ?37Kc,o
int totalCount = r`=!4vY2
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((Integer) criteria.setProjection(Projections.rowCount JMYM}G
cM+s)4TPL
()).uniqueResult()).intValue(); d,).O
criteria.setProjection R$40cW3`
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(null); =kWm9W<^
List items = <j89HtCz
0 Pa\:^/6
criteria.setFirstResult(startIndex).setMaxResults RiAY>:
sJ/?R:
(pageSize).list(); YR/rN,
PaginationSupport ps = DadlCEZv
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new PaginationSupport(items, totalCount, pageSize, \c$!C8z
8|p*T&Cn&
startIndex); a?9Ka!O4s
return ps; >&N8Du*[
} M&O .7B1}
}, true); w6l8RNRe
} -J*jW
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public List findAllByCriteria(final owc#RW9 7
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DetachedCriteria detachedCriteria){ 3YPoObY
return(List) getHibernateTemplate CVBy&o"6A
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().execute(new HibernateCallback(){ .B9rG~
publicObject doInHibernate wrW768WR
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(Session session)throws HibernateException { t.oP]_mI
Criteria criteria = p2~MJ
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detachedCriteria.getExecutableCriteria(session); "8Y4;lbN.q
return criteria.list(); lGZ^ 8
} kC)ye"r
}, true); VDq?,4Kb
} 7*r7Q'
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public int getCountByCriteria(final LHz-/0[
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DetachedCriteria detachedCriteria){ "(rG5z3P
Integer count = (Integer) NrdbXPHceN
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getHibernateTemplate().execute(new HibernateCallback(){ {` Lem
publicObject doInHibernate cvvba 60
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(Session session)throws HibernateException { n-n{+Dl!
Criteria criteria = vHPp$lql
p M:lg
detachedCriteria.getExecutableCriteria(session); X4U$#uI{
return HW(cA}$
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criteria.setProjection(Projections.rowCount V'4sOn
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()).uniqueResult(); fWywegh
} g2v0!
}, true); -&*
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return count.intValue(); J!,<NlP0K
} &i,xod6$
} Vn-y<*np
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用户在web层构造查询条件detachedCriteria,和可选的 I=)u:l c
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startIndex,调用业务bean的相应findByCriteria方法,返回一个 R(sPU>`MX
? -PRS.=%
PaginationSupport的实例ps。 ) )q4Rh
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ps.getItems()得到已分页好的结果集 c-L1 Bkw
ps.getIndexes()得到分页索引的数组 B6&;nU>;
ps.getTotalCount()得到总结果数 1o. O]>
ps.getStartIndex()当前分页索引 oZkjg3
ps.getNextIndex()下一页索引 YzqUOMAt"V
ps.getPreviousIndex()上一页索引 I65W^b4y
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连续看了两篇robbin有关DetachedCriteria的介绍,感觉真的不错 +,&8U&~`
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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 N|OI~boV%
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一下代码重构了。 v&p|9C@
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我把原本我的做法也提供出来供大家讨论吧: 5J^S-K^r
82.::J'e
首先,为了实现分页查询,我封装了一个Page类: J|-X?V;ZW
java代码: x78`dX
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/*Created on 2005-4-14*/ A{Jp>15AVg
package org.flyware.util.page; $^F
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UMN3.-4K#
/** YL_M=h>P
* @author Joa | N%?7PZ(
* C:+-T+m[
*/ kQ5mIJ9(
publicclass Page { 5\MCk "R!
>YwvM=b"V
/** imply if the page has previous page */ ztcV[{[g
privateboolean hasPrePage; n.&z^&$w\)
K}e%E&|>
/** imply if the page has next page */ &eL02:[
privateboolean hasNextPage; $9!2c /
+ML4.$lc^
/** the number of every page */ i^9 ,. $<1
privateint everyPage; =]k0*\PS
),ur!v
/** the total page number */ LO8`qq*rq
privateint totalPage; SJg4P4|
V(hM@ztN
/** the number of current page */ F7!g+LPc<
privateint currentPage; zPzy0lx
&\8qN_`
/** the begin index of the records by the current _Mi`]VSq9
]}t6V]`Q
query */ Wt|IKCx
privateint beginIndex; .ME>ICA
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/** The default constructor */
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public Page(){ u^HC1r|%
^U"$uJz!c
} #NU@7Q[4
P%VEJ5,]b
/** construct the page by everyPage 6V{Sf9V|
* @param everyPage LH7m >/LJr
* */ *3.K; Ic;
public Page(int everyPage){ kiYHJ\a
this.everyPage = everyPage; GtR!a
} ! =(OvX_<
rC`pTN
/** The whole constructor */ CD}::7$
public Page(boolean hasPrePage, boolean hasNextPage, 6_Ps*Ed
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int everyPage, int totalPage, -;NGS
)RM
int currentPage, int beginIndex){ t6/w({}j
this.hasPrePage = hasPrePage; LqNt.d @
this.hasNextPage = hasNextPage; HQtR;[1
this.everyPage = everyPage; 52X[{
this.totalPage = totalPage;
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this.currentPage = currentPage; &B1j,$NRc
this.beginIndex = beginIndex; b#~K>
} PHQ7
k
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/** _}bs0 kIz
* @return cs+;ijp
* Returns the beginIndex. b|SDg%e
*/ Q]/ZVcoqo
publicint getBeginIndex(){ C K#^`w
return beginIndex; p**Sd[|
} {KQ-QKxxS
>:o$h2
/** {}.M(nPtv;
* @param beginIndex 7+!FZo{?
* The beginIndex to set. O0Z!*Hy
*/ ^/6LVB *
publicvoid setBeginIndex(int beginIndex){ 1zNh&
"
this.beginIndex = beginIndex; vIq>QXb;d
} '80mhrEutG
wh Hp}r
/** %#go9H(K
* @return _HMQx_e0YM
* Returns the currentPage. k)j6rU
*/ ={'3j
publicint getCurrentPage(){ g=#Cc(
q
return currentPage; 4{PN9i
E
} O)N$nBnp
,xSNTOJ
/** e1<9:h+
* @param currentPage =EJ8J;y_f
* The currentPage to set. qjr:(x /
*/ S_eD1iY2-
publicvoid setCurrentPage(int currentPage){ PJfADB7Y
this.currentPage = currentPage; Y0z)5),[U:
} 8SZZ_tS3r
hkpS}*L9o
/** uSsP'qd
* @return 5q^5DH_;
* Returns the everyPage. /1y\EEc
*/ 'hGUsi
publicint getEveryPage(){ oV/:T\Qn=
return everyPage; H*.v*ro9_
} K#%@4]jO3
C.|.0^5
/** q1^bH6*fl
* @param everyPage ,kQCCn]
* The everyPage to set. X-4(oE
*/ iv!; gMco
publicvoid setEveryPage(int everyPage){ +X%pUe
this.everyPage = everyPage;
l;;,[xhq
} UuKW`(?^
/4I9Elr
/** "F[e~S#V*
* @return #x+7-hi
* Returns the hasNextPage. i,h)VCc
*/ T^ )\
publicboolean getHasNextPage(){ m$.7) 24
return hasNextPage; .DR*MQI9
} <`V_H~Z
([ jm=[E^
/** <@S'vcO
* @param hasNextPage Leu6kPk
* The hasNextPage to set. oA* 88c+{f
*/ A(D>Zh6 o@
publicvoid setHasNextPage(boolean hasNextPage){ u?4d<%5R!
this.hasNextPage = hasNextPage; @?n~v^
} NwcRH9};i
&W8fEQwa
/** ,Mr_F^|
* @return .: Zw6
* Returns the hasPrePage. lyS`X
*/ Fy*t[>
publicboolean getHasPrePage(){ `t7z
LC^c
return hasPrePage; :u,Ji9
u
} h1~/zM/`
7](aPm8
/** no$X0ia
* @param hasPrePage {zI>"%$u
* The hasPrePage to set.
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*/ kp-`_sDg
publicvoid setHasPrePage(boolean hasPrePage){ g_3Ozy
this.hasPrePage = hasPrePage; 3dx.%~c
} WCYVon bg"
?!.L#]23f
/** % !>@m6JK
* @return Returns the totalPage. s7(1|}jh
* *x/H
*/ R('\i/fy
publicint getTotalPage(){ mwMc AUD]2
return totalPage; >l b9 j>
} Ub{7 Xk
n
Y1;jRIOA
/** {(IHHA>
* @param totalPage 3V]08
* The totalPage to set. )b~+\xL5J
*/ hZ|8mV
publicvoid setTotalPage(int totalPage){ 12V-EG i
this.totalPage = totalPage; #~o<9O
} Hf+oG
N(kSE^skOa
} ?X+PNw|pf
C1uV7t*\
zWrynJ}s
L0R$T=~%)
%KPQ|^WE
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 F@KtRUxE
Gs>4/
个PageUtil,负责对Page对象进行构造: o]eG+i6g]
java代码: C{G;G@/7
Byh!Snoe
dG!) <
/*Created on 2005-4-14*/ dbg%n 0h
package org.flyware.util.page; .:t&LC][
`k7X|
import org.apache.commons.logging.Log; eF(oHn,
import org.apache.commons.logging.LogFactory; NE><(02qW
` Nv1sA#C
/** QBCEDv&j
* @author Joa R"{P#U,HNO
* $T_>WUiK
*/ +Mb}70^
publicclass PageUtil { jItVAmC=i
;D<;pW
privatestaticfinal Log logger = LogFactory.getLog l\TL=8u2c
6n\){dkZ~
(PageUtil.class); 5~OKKSUmT
Jv8VM\*
/** VHLt,?G
* Use the origin page to create a new page yuhY )T
* @param page xJin%:O
* @param totalRecords <r)5jf
* @return t^=S\1"R\
*/ ,uD}1
G<u
publicstatic Page createPage(Page page, int [[O4_)?el
;3iWV"&_A
totalRecords){ Q$5%9
return createPage(page.getEveryPage(), 4WPco"xH!
j>5X^Jd
page.getCurrentPage(), totalRecords); dpT?*qLM
} L lD=c
w3;T]R*
/** |+Xh ^E
* the basic page utils not including exception hbSKlb0d
Of-8n-
handler EgRuB@lw76
* @param everyPage Rsx?8Y^5
* @param currentPage B}@CtVWFz
* @param totalRecords Lie= DD
* @return page `,Fc271`
*/ /Ri-iC >
publicstatic Page createPage(int everyPage, int 6%V#_]
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currentPage, int totalRecords){ R8Dn
GR
everyPage = getEveryPage(everyPage); 0S\HO<~k
currentPage = getCurrentPage(currentPage); )>N=B 2P
int beginIndex = getBeginIndex(everyPage, lI3d
_cU
p::`1
currentPage); @vO~'Xxq!
int totalPage = getTotalPage(everyPage,
QrLXAK\5
H {uR+&<
totalRecords); g(R!M0hdF
boolean hasNextPage = hasNextPage(currentPage, 'X~CrgQl
6&btAwvOHx
totalPage); >}r
1A
boolean hasPrePage = hasPrePage(currentPage); lr[&*v?h
gu1n0N`b
returnnew Page(hasPrePage, hasNextPage, !N/?b^y
everyPage, totalPage, 0IQ|`C.
currentPage, KcM+8W\
a
fB?js6
beginIndex); [9Hrpo]tU:
} %htbEKWR
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privatestaticint getEveryPage(int everyPage){ KssIoP
return everyPage == 0 ? 10 : everyPage; P u}PE-b
} GPAz#0p
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privatestaticint getCurrentPage(int currentPage){ JY9hD;`6y
return currentPage == 0 ? 1 : currentPage; 1#x@
} lgC^32y
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privatestaticint getBeginIndex(int everyPage, int ^ lG^.
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currentPage){ scZ'/(b-E
return(currentPage - 1) * everyPage; $oIGlKc:L
} iJk/fvi
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privatestaticint getTotalPage(int everyPage, int *jl_,0g]
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totalRecords){ u73/#!(1=H
int totalPage = 0; V6b)
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if(totalRecords % everyPage == 0) mZ.E;X& ,*
totalPage = totalRecords / everyPage; t`0(5v
else ^ |>)H
totalPage = totalRecords / everyPage + 1 ; 7T?7KS
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return totalPage; X6oY-4O
} 'x=y:0A
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privatestaticboolean hasPrePage(int currentPage){ `(L<Q%
return currentPage == 1 ? false : true; e(k$k>?
} WhL1OG
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privatestaticboolean hasNextPage(int currentPage, 9R|B 5.
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int totalPage){ NAfu$7
return currentPage == totalPage || totalPage == 0>0:ls
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0 ? false : true; BYs^?IfW
} !B&1{
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} |)Sx"B)
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上面的这两个对象与具体的业务逻辑无关,可以独立和抽象。 h_h6@/1l
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面对一个具体的业务逻辑:分页查询出User,每页10个结果。具体 e7gWz~
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做法如下: %suXp,j
1. 编写一个通用的结果存储类Result,这个类包含一个Page对象 .g6(07TyV
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的信息,和一个结果集List: N+NS\Y5
java代码: %i`YJ
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/*Created on 2005-6-13*/ (?zZvW8
package com.adt.bo; lb`2a3W/
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import java.util.List; siGt5RH*
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import org.flyware.util.page.Page; 5P
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/** pmi`Er
* @author Joa mH09*
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*/ %D}]Z=gp
publicclass Result { g,cl|]/\d
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private Page page; |CjE}5Op>
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private List content; Oo95\Yf$N
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/** &