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	title:?JSP分頁技術(shù)實現(xiàn)
          summary:使用工具類實現(xiàn)通用分頁處理
          author:?evan_zhao
          email:?evan_zhao@hotmail.com
          from:http://www.javaresearch.org/article/showarticle.jsp?column=106&thread=8893

          　　目前比較廣泛使用的分頁方式是將查詢結(jié)果緩存在HttpSession或有狀態(tài)bean中，翻頁的時候從緩存中取出一頁數(shù)據(jù)顯示。這種方法有兩個主要的缺點：一是用戶可能看到的是過期數(shù)據(jù)；二是如果數(shù)據(jù)量非常大時第一次查詢遍歷結(jié)果集會耗費(fèi)很長時間，并且緩存的數(shù)據(jù)也會占用大量內(nèi)存，效率明顯下降。
          　　其它常見的方法還有每次翻頁都查詢一次數(shù)據(jù)庫，從ResultSet中只取出一頁數(shù)據(jù)（使用rs.last();rs.getRow()獲得總計錄條數(shù)，使用rs.absolute()定位到本頁起始記錄）。這種方式在某些數(shù)據(jù)庫(如oracle)的JDBC實現(xiàn)中差不多也是需要遍歷所有記錄，實驗證明在記錄數(shù)很大時速度非常慢。
          　　至于緩存結(jié)果集ResultSet的方法則完全是一種錯誤的做法。因為ResultSet在Statement或Connection關(guān)閉時也會被關(guān)閉，如果要使ResultSet有效勢必長時間占用數(shù)據(jù)庫連接。

          　　因此比較好的分頁做法應(yīng)該是每次翻頁的時候只從數(shù)據(jù)庫里檢索頁面大小的塊區(qū)的數(shù)據(jù)。這樣雖然每次翻頁都需要查詢數(shù)據(jù)庫，但查詢出的記錄數(shù)很少，網(wǎng)絡(luò)傳輸數(shù)據(jù)量不大，如果使用連接池更可以略過最耗時的建立數(shù)據(jù)庫連接過程。而在數(shù)據(jù)庫端有各種成熟的優(yōu)化技術(shù)用于提高查詢速度，比在應(yīng)用服務(wù)器層做緩存有效多了。

          　　在oracle數(shù)據(jù)庫中查詢結(jié)果的行號使用偽列ROWNUM表示（從1開始）。例如select?*? from?employee?where?rownum<10?返回前10條記錄。但因為rownum是在查詢之后排序之前賦值的，所以查詢employee按birthday排序的第100到120條記錄應(yīng)該這么寫：
          ????????select?*?from?(
          ????????????select?my_table.*,?rownum?as?my_rownum?from?(
          ????????????????select?name,?birthday?from?employee?order?by?birthday
          ????????????)?my_table?where?rownum?<120
          ????????)?where?my_rownum>=100

          　　mySQL可以使用LIMIT子句：
          　　　　select?name,?birthday?from?employee?order?by?birthday?LIMIT?99,20
          　　DB2有rownumber()函數(shù)用于獲取當(dāng)前行數(shù)。
          　　SQL?Server沒研究過，可以參考這篇文章：http://www.csdn.net/develop/article/18/18627.shtm

          　　在Web程序中分頁會被頻繁使用，但分頁的實現(xiàn)細(xì)節(jié)卻是編程過程中比較麻煩的事情。大多分頁顯示的查詢操作都同時需要處理復(fù)雜的多重查詢條件，sql語句需要動態(tài)拼接組成，再加上分頁需要的記錄定位、總記錄條數(shù)查詢以及查詢結(jié)果的遍歷、封裝和顯示，程序會變得很復(fù)雜并且難以理解。因此需要一些工具類簡化分頁代碼，使程序員專注于業(yè)務(wù)邏輯部分。下面是我設(shè)計的兩個工具類：
          　　PagedStatement??封裝了數(shù)據(jù)庫連接、總記錄數(shù)查詢、分頁查詢、結(jié)果數(shù)據(jù)封裝和關(guān)閉數(shù)據(jù)庫連接等操作，并使用了PreparedStatement支持動態(tài)設(shè)置參數(shù)。
          　　RowSetPage? ?參考PetStore的page?by?page?iterator模式，?設(shè)計 RowSetPage用于封裝查詢結(jié)果（使用OracleCachedRowSet緩存查詢出的一頁數(shù)據(jù)，關(guān)于使用CachedRowSet封裝數(shù)據(jù)庫查詢結(jié)果請參考JSP頁面查詢顯示常用模式）以及當(dāng)前頁碼、總記錄條數(shù)、當(dāng)前記錄數(shù)等信息，?并且可以生成簡單的HTML分頁代碼。
          　　PagedStatement?查詢的結(jié)果封裝成RowsetPage。

          　　下面是簡單的使用示例：

          2. ????//DAO查詢數(shù)據(jù)部分代碼：
          3. ????… 

          4. ????public?RowSetPage?getEmployee(String?gender,?int?pageNo)?throws?Exception{ 

          5. ????????String?sql="select?emp_id,?emp_code,??user_name,?real_name?from?employee?where?gender?=?"; 

          6. ???????//使用Oracle數(shù)據(jù)庫的分頁查詢實現(xiàn),每頁顯示5條
          7. ????????PagedStatement?pst?=new?PagedStatementOracleImpl(sql,??pageNo,?5); 

          8. ????????pst.setString(1,?gender); 

          9. ????????return?pst.executeQuery(); 

          10. ????} 



          13. ????//Servlet處理查詢請求部分代碼：

          15. ????… 

          16. ????int?pageNo; 

          17. ????try{ 

          18. ????????//可以通過參數(shù)pageno獲得用戶選擇的頁碼
          19. ????????pageNo?=?Integer.parseInt(request.getParameter("pageno")?); 

          20. ????}catch(Exception?ex){ 

          21. ????????//默認(rèn)為第一頁
          22. ????????pageNo=1; 

          23. ????} 

          24. ????String?gender?=?request.getParameter("gender"?); 

          25. ????request.setAttribute("empPage",?myBean.getEmployee(gender,?pageNo)?); 

          26. ????… 


          28. ????//JSP顯示部分代碼
          29. <%@?page?import?=?"page.RowSetPage"%> 

          30. ????… 

          31. ????<script?language="javascript"> 

          32. ????????function?doQuery(){ 

          33. ????????????form1.actionType.value="doQuery"; 

          34. ????????????form1.submit(); 

          35. ????} 

          36. ????</script> 

          37. ????… 

          38. ????<form?name=form1?method=get> 

          39. ??????<input?type=hidden?name=actionType> 

          40. ??????性別： 

          41. ??????<input?type=text?name=gender?size=1?value="<%=request.getParameter("gender")%>"> 

          42. ??????<input?type=button?value="?查詢?"?onclick="doQuery()"> 

          43. <% 

          44. ????RowSetPage?empPage?=?(RowSetPage)request.getAttribute("empPage"); 

          45. ????if?(empPage?==?null?)?empPage?=?RowSetPage.EMPTY_PAGE; 

          46. %> 

          47. ????… 

          48. ????<table??cellspacing="0"?width="90%"> 

          49. ????????<tr>? <td>ID</td>?<td>代碼</td>?<td>用戶名 </td>?<td>姓名</td>??</tr> 

          50. <% 

          51. ????javax.sql.RowSet?empRS?=?(javax.sql.RowSet)?empPage.getRowSet(); 

          52. ????if?(empRS!=null)?while?(empRS.next()?)?{ 

          53. %> 

          54. ????????<tr>?? 

          55. ????????????<td><%=?empRS.getString("EMP_ID")%></td>? 

          56. ????????????<td><%=?empRS.getString("EMP_CODE")%></td>?? 

          57. ????????????<td><%=?empRS.getString("USER_NAME")%></td>? 

          58. ????????????<td><%=?empRS.getString("REAL_NAME")%></td>?? 

          59. ????????</tr> 

          60. <% 

          61. ????}//?end?while
          62. %> 

          63. ????????<tr> 

          64. <% 

          65. ????//顯示總頁數(shù)和當(dāng)前頁數(shù)(pageno)以及分頁代碼。
          66. ????//此處doQuery為頁面上提交查詢動作的javascript函數(shù)名，?pageno為標(biāo)識當(dāng)前頁碼的參數(shù)名
          67. %> 

          68. ????????????<td?colspan=4><%=?empPage?.getHTML("doQuery",?"pageno")%></td> 

          69. ????????</tr> 

          70. ????</table> 

          71. ????</form> 

          　　效果如圖：


          　　因為分頁顯示一般都會伴有查詢條件和查詢動作，頁面應(yīng)已經(jīng)有校驗查詢條件和提交查詢的javascript方法（如上面的doQuery），所以 RowSetPage.getHTML()生成的分頁代碼在用戶選擇新頁碼時直接回調(diào)前面的處理提交查詢的javascript方法。注意在顯示查詢結(jié)果的時候上次的查詢條件也需要保持，如<input?type=text?name=gender?size= 1?value="<%=request.getParameter("gender")%>">。同時由于頁碼的參數(shù)名可以指定，因此也支持在同一頁面中有多個分頁區(qū)。
          　　另一種分頁代碼實現(xiàn)是生成每一頁的URL，將查詢參數(shù)和頁碼作為QueryString附在URL后面。這種方法的缺陷是在查詢條件比較復(fù)雜時難以處理，并且需要指定處理查詢動作的servlet，可能不適合某些定制的查詢操作。
          　　如果對RowSetPage.getHTML()生成的默認(rèn)分頁代碼不滿意可以編寫自己的分頁處理代碼，RowSetPage提供了很多getter方法用于獲取相關(guān)信息（如當(dāng)前頁碼、總頁數(shù)、?總記錄數(shù)和當(dāng)前記錄數(shù)等）。
          　　在實際應(yīng)用中可以將分頁查詢和顯示做成jsp?taglib，?進(jìn)一步簡化JSP代碼，屏蔽Java?Code。

          附：分頁工具類的源代碼，?有注釋，應(yīng)該很容易理解。

          1.Page.java
          2.RowSetPage.java(RowSetPage繼承Page)
          3.PagedStatement.java
          4.PagedStatementOracleImpl.java(PagedStatementOracleImpl繼承PagedStatement)



          您可以任意使用這些源代碼，但必須保留author?evan_zhao@hotmail.com字樣

          2. ///////////////////////////////////
          3. //
          4. //??Page.java
          5. //??author:?evan_zhao@hotmail.com
          6. //
          7. ///////////////////////////////////

          9. package?page; 


          11. import?java.util.List; 

          12. import?java.util.ArrayList; 

          13. import?java.util.Collection; 

          14. import?java.util.Collections; 



          17. /**
          18. ?*?Title:?分頁對象<br>
          19. ?*?Description:??用于包含數(shù)據(jù)及分頁信息的對象<br>
          20. ?*?????? ?????????Page類實現(xiàn)了用于顯示分頁信息的基本方法，但未指定所含數(shù)據(jù)的類型，
          21. ?*???????????????可根據(jù)需要實現(xiàn)以特定方式組織數(shù)據(jù)的子類，<br>
          22. ?*?????? ?????????如RowSetPage以RowSet 封裝數(shù)據(jù)，ListPage以List封裝數(shù)據(jù)<br>
          23. ?*?Copyright:????Copyright?(c)?2002?<br>
          24. ?*?@author?evan_zhao@hotmail.com?<br>
          25. ?*?@version?1.0
          26. ?*/
          27. public??class?Page?implements?java.io.Serializable?{ 

          28. ????public?static?final?Page?EMPTY_PAGE?=?new?Page(); 

          29. ????public?static?final?int??DEFAULT_PAGE_SIZE?=?20; 

          30. ????public?static?final??int?MAX_PAGE_SIZE?=?9999; 


          32. ????private?int?myPageSize?=?DEFAULT_PAGE_SIZE; 


          34. ????private?int?start; 

          35. ????private?int?avaCount,totalSize; 

          36. ????private?Object?data; 


          38. ????private?int?currentPageno; 

          39. ????private?int?totalPageCount; 


          41. ????/**
          42. ?????*?默認(rèn)構(gòu)造方法，只構(gòu)造空頁
          43. ?????*/
          44. ????protected?Page(){ 

          45. ????????this.init(0,0,0,DEFAULT_PAGE_SIZE,new?Object()); 

          46. ????} 


          48. ????/**
          49. ?????*?分頁數(shù)據(jù)初始方法，由子類調(diào)用
          50. ?????*?@param?start?本頁數(shù)據(jù)在數(shù)據(jù)庫中的起始位置
          51. ?????*?@param?avaCount?本頁包含的數(shù)據(jù)條數(shù)
          52. ?????*?@param?totalSize?數(shù)據(jù)庫中總記錄條數(shù)
          53. ?????*?@param?pageSize?本頁容量
          54. ?????*?@param?data?本頁包含的數(shù)據(jù)
          55. ?????*/
          56. ????protected?void?init(int?start,?int?avaCount,?int?totalSize,?int?pageSize,?Object?data){ 


          58. ????????this.avaCount?=avaCount; 

          59. ????????this.myPageSize?=?pageSize; 


          61. ????????this.start?=?start; 

          62. ????????this.totalSize?=?totalSize; 


          64. ????????this.data=data; 


          66. ????????//System.out.println("avaCount:"+avaCount);
          67. ????????//System.out.println("totalSize:"+totalSize);
          68. ????????if?(avaCount>totalSize)?{ 

          69. ????????????//throw?new?RuntimeException("記錄條數(shù)大于總條數(shù)？！");
          70. ????????} 


          72. ????????this.currentPageno?=?(start?-1)/pageSize?+1; 

          73. ????????this.totalPageCount?=?(totalSize?+?pageSize?-1)?/?pageSize; 


          75. ????????if?(totalSize==0?&&?avaCount==0){ 

          76. ????????????this.currentPageno?=?1; 

          77. ????????????this.totalPageCount?=?1; 

          78. ????????} 

          79. ????????//System.out.println("Start?Index?to?Page?No:?"?+?start?+?"-"?+?currentPageno);
          80. ????} 


          82. ????public??Object?getData(){ 

          83. ????????return?this.data; 

          84. ????} 


          86. ????/**
          87. ?????*?取本頁數(shù)據(jù)容量（本頁能包含的記錄數(shù)）
          88. ?????*?@return?本頁能包含的記錄數(shù)
          89. ?????*/
          90. ????public?int?getPageSize(){ 

          91. ????????return?this.myPageSize; 

          92. ????} 


          94. ????/**
          95. ?????*?是否有下一頁
          96. ?????*?@return?是否有下一頁
          97. ?????*/
          98. ????public?boolean?hasNextPage()?{ 

          99. ??????/*
          100. ????????if?(avaCount==0?&&?totalSize==0){
          101. ????????????return?false;
          102. ????????}
          103. ????????return?(start?+?avaCount?-1)?<?totalSize;
          104. ???????*/
          105. ??????return?(this.getCurrentPageNo()<this.getTotalPageCount()); 

          106. ????} 


          108. ????/**
          109. ?????*?是否有上一頁
          110. ?????*?@return??是否有上一頁
          111. ?????*/
          112. ????public?boolean?hasPreviousPage()?{ 

          113. ??????/*
          114. ????????return?start?>?1;
          115. ???????*/
          116. ??????return?(this.getCurrentPageNo()>1); 

          117. ????} 


          119. ????/**
          120. ?????*?獲取當(dāng)前頁第一條數(shù)據(jù)在數(shù)據(jù)庫中的位置
          121. ?????*?@return
          122. ?????*/
          123. ????public?int?getStart(){ 

          124. ????????return?start; 

          125. ????} 


          127. ????/**
          128. ?????*?獲取當(dāng)前頁最后一條數(shù)據(jù)在數(shù)據(jù)庫中的位置
          129. ?????*?@return
          130. ?????*/
          131. ????public?int?getEnd(){ 

          132. ????????int?end?=?this.getStart()?+?this.getSize()?-1; 

          133. ????????if?(end<0)?{ 

          134. ????????????end?=?0; 

          135. ????????} 

          136. ????????return?end; 

          137. ????} 


          139. ????/**
          140. ?????*?獲取上一頁第一條數(shù)據(jù)在數(shù)據(jù)庫中的位置
          141. ?????*?@return?記錄對應(yīng)的rownum
          142. ?????*/
          143. ????public?int?getStartOfPreviousPage()?{ 

          144. ????????return?Math.max(start-myPageSize,?1); 

          145. ????} 



          148. ????/**
          149. ?????*?獲取下一頁第一條數(shù)據(jù)在數(shù)據(jù)庫中的位置
          150. ?????*?@return?記錄對應(yīng)的rownum
          151. ?????*/
          152. ????public?int?getStartOfNextPage()?{ 

          153. ????????return?start?+?avaCount; 

          154. ????} 


          156. ????/**
          157. ?????*?獲取任一頁第一條數(shù)據(jù)在數(shù)據(jù)庫中的位置，每頁條數(shù)使用默認(rèn)值
          158. ?????*?@param?pageNo?頁號
          159. ?????*?@return?記錄對應(yīng)的rownum
          160. ?????*/
          161. ????public?static?int?getStartOfAnyPage(int?pageNo){ 

          162. ????????return?getStartOfAnyPage(pageNo,?DEFAULT_PAGE_SIZE); 

          163. ????} 


          165. ????/**
          166. ?????*?獲取任一頁第一條數(shù)據(jù)在數(shù)據(jù)庫中的位置
          167. ?????*?@param?pageNo?頁號
          168. ?????*?@param?pageSize?每頁包含的記錄數(shù)
          169. ?????*?@return?記錄對應(yīng)的rownum
          170. ?????*/
          171. ????public?static?int?getStartOfAnyPage(int?pageNo,?int?pageSize){ 

          172. ????????int?startIndex?=?(pageNo-1)?*?pageSize?+?1; 

          173. ????????if?(?startIndex?<?1)?startIndex?=?1; 

          174. ????????//System.out.println("Page?No?to?Start?Index:?"?+?pageNo?+?"-"?+?startIndex);
          175. ????????return?startIndex; 

          176. ????} 


          178. ????/**
          179. ?????*?取本頁包含的記錄數(shù)
          180. ?????*?@return?本頁包含的記錄數(shù)
          181. ?????*/
          182. ????public?int?getSize()?{ 

          183. ????????return?avaCount; 

          184. ????} 


          186. ????/**
          187. ?????*?取數(shù)據(jù)庫中包含的總記錄數(shù)
          188. ?????*?@return?數(shù)據(jù)庫中包含的總記錄數(shù)
          189. ?????*/
          190. ????public?int?getTotalSize()?{ 

          191. ????????return?this.totalSize; 

          192. ????} 


          194. ????/**
          195. ?????*?取當(dāng)前頁碼
          196. ?????*?@return?當(dāng)前頁碼
          197. ?????*/
          198. ????public?int?getCurrentPageNo(){ 

          199. ????????return??this.currentPageno; 

          200. ????} 


          202. ????/**
          203. ?????*?取總頁碼
          204. ?????*?@return?總頁碼
          205. ?????*/
          206. ????public?int?getTotalPageCount(){ 

          207. ????????return?this.totalPageCount; 

          208. ????} 



          211. ????/**
          212. ?????*
          213. ?????*?@param?queryJSFunctionName?實現(xiàn)分頁的JS腳本名字，頁碼變動時會自動回調(diào)該方法
          214. ?????*?@param?pageNoParamName?頁碼參數(shù)名稱
          215. ?????*?@return
          216. ?????*/
          217. ????public?String?getHTML(String?queryJSFunctionName,?String?pageNoParamName){ 

          218. ????????if?(getTotalPageCount()<1){ 

          219. ????????????return?"<input?type='hidden'?name='"+pageNoParamName+"'?value='1'?>"; 

          220. ????????} 

          221. ????????if?(queryJSFunctionName?==?null?||?queryJSFunctionName.trim().length()<1)?{ 

          222. ????????????queryJSFunctionName?=?"gotoPage"; 

          223. ????????} 

          224. ????????if?(pageNoParamName?==?null?||?pageNoParamName.trim().length()<1){ 

          225. ????????????pageNoParamName?=?"pageno"; 

          226. ????????} 


          228. ????????String?gotoPage?=?"_"+queryJSFunctionName; 


          230. ????????StringBuffer?html?=?new?StringBuffer("\n"); 

          231. ????????html.append("<script?language=\"Javascript1.2\">\n") 

          232. ?????????????.append("function?").append(gotoPage).append("(pageNo){??\n") 

          233. ?????????????.append(??"???var?curPage=1;??\n") 

          234. ?????????????.append(??"???try{?curPage?=?document.all[\"") 

          235. ?????????????.append(pageNoParamName).append("\"].value;??\n") 

          236. ?????????????.append(??"????????document.all[\"").append(pageNoParamName) 

          237. ?????????????.append("\"].value?=?pageNo;??\n") 

          238. ?????????????.append(??"????????").append(queryJSFunctionName).append("(pageNo);?\n") 

          239. ?????????????.append(??"????????return?true;??\n") 

          240. ?????????????.append(??"???}catch(e){?\n") 

          241. //?????????????.append(??"??????try{?\n")
          242. //?????????????.append(??"???????????document.forms[0].submit();??\n")
          243. //?????????????.append(??"??????}catch(e){???\n")
          244. ?????????????.append(??"??????????alert('尚未定義查詢方法：function?") 

          245. ?????????????.append(queryJSFunctionName).append("()');?\n") 

          246. ?????????????.append(??"??????????document.all[\"").append(pageNoParamName) 

          247. ?????????????.append("\"].value?=?curPage;??\n") 

          248. ?????????????.append(??"??????????return?false;??\n") 

          249. //?????????????.append(??"??????}??\n")
          250. ?????????????.append(??"???}??\n") 

          251. ?????????????.append(??"}") 

          252. ?????????????.append(??"</script>??\n") 

          253. ?????????????.append(??""); 

          254. ????????html.append(?"<table??border=0?cellspacing=0?cellpadding=0?align=center?width=80%>??\n") 

          255. ?????????????.append(?"??<tr>??\n") 

          256. ?????????????.append(?"????<td?align=left><br>??\n"); 

          257. ????????html.append(??"???????共"?).append(?getTotalPageCount()?).append(?"頁") 

          258. ?????????????.append(??"???????[")?.append(getStart()).append("..").append(getEnd()) 

          259. ?????????????.append("/").append(this.getTotalSize()).append("]??\n") 

          260. ?????????????.append(?"????</td>??\n") 

          261. ?????????????.append(?"????<td?align=right>??\n"); 

          262. ????????if?(hasPreviousPage()){ 

          263. ?????????????html.append(?"[<a?href='javascript:").append(gotoPage) 

          264. ?????????????.append("(")?.append(getCurrentPageNo()-1)? 

          265. ?????????????.append(?")'>上一頁</a>]???\n"); 

          266. ????????} 

          267. ????????html.append(??"???????第") 

          268. ?????????????.append(???"????????<select?name='") 

          269. ?????????????.append(pageNoParamName).append("'?onChange='javascript:") 

          270. ?????????????.append(gotoPage).append("(this.value)'>\n"); 

          271. ????????String?selected?=?"selected"; 

          272. ????????for(int?i=1;i<=getTotalPageCount();i++){ 

          273. ????????????if(?i?==?getCurrentPageNo()?) 

          274. ?????????????????selected?=?"selected"; 

          275. ????????????else?selected?=?""; 

          276. ????????????html.append(?"??????<option?value='").append(i).append("'?") 

          277. ??????????????.append(selected).append(">").append(i).append("</option>??\n"); 

          278. ????????} 

          279. ????????if?(getCurrentPageNo()>getTotalPageCount()){ 

          280. ????????????html.append(?"??????<option?value='").append(getCurrentPageNo()) 

          281. ????????????.append("'?selected>").append(getCurrentPageNo()) 

          282. ????????????.append("</option>??\n"); 

          283. ????????} 

          284. ????????html.append(?"????</select>頁??\n"); 

          285. ????????if?(hasNextPage()){ 

          286. ?????????????html.append(?"????[<a?href='javascript:").append(gotoPage) 

          287. ???????????????.append("(").append((getCurrentPageNo()+1))? 

          288. ???????????????.append(?")'>下一頁</a>]???\n"); 

          289. ????????} 

          290. ????????html.append(?"</td></tr></table>??\n"); 


          292. ????????return?html.toString(); 


          294. ????} 

          295. } 





          300. ///////////////////////////////////
          301. //
          302. //??RowSetPage.java
          303. //??author:?evan_zhao@hotmail.com
          304. //
          305. ///////////////////////////////////
          306. package?page; 


          308. import?javax.sql.RowSet; 



          311. /**
          312. ?*?<p>Title:?RowSetPage</p>
          313. ?*?<p>Description:?使用RowSet封裝數(shù)據(jù)的分頁對象</p>
          314. ?*?<p>Copyright:?Copyright?(c)?2003</p>
          315. ?*?@author?evan_zhao@hotmail.com
          316. ?*?@version?1.0
          317. ?*/

          319. public?class?RowSetPage?extends?Page?{ 

          320. ????private?javax.sql.RowSet?rs; 


          322. ????/**
          323. ?????*空頁
          324. ?????*/
          325. ????public?static?final?RowSetPage?EMPTY_PAGE?=?new?RowSetPage(); 


          327. ????/**
          328. ?????*默認(rèn)構(gòu)造方法，創(chuàng)建空頁
          329. ?????*/
          330. ????public?RowSetPage(){ 

          331. ??????this(null,?0,0); 

          332. ????} 


          334. ????/**
          335. ?????*構(gòu)造分頁對象
          336. ?????*@param?crs?包含一頁數(shù)據(jù)的OracleCachedRowSet
          337. ?????*@param?start?該頁數(shù)據(jù)在數(shù)據(jù)庫中的起始位置
          338. ?????*@param?totalSize?數(shù)據(jù)庫中包含的記錄總數(shù)
          339. ?????*/
          340. ????public?RowSetPage(RowSet?crs,?int?start,?int?totalSize)?{ 

          341. ????????this(crs,start,totalSize,Page.DEFAULT_PAGE_SIZE); 

          342. ????} 


          344. ????/**
          345. ?????*構(gòu)造分頁對象
          346. ?????*@param?crs?包含一頁數(shù)據(jù)的OracleCachedRowSet
          347. ?????*@param?start?該頁數(shù)據(jù)在數(shù)據(jù)庫中的起始位置
          348. ?????*@param?totalSize?數(shù)據(jù)庫中包含的記錄總數(shù)
          349. ?????*@pageSize?本頁能容納的記錄數(shù)
          350. ?????*/
          351. ????public?RowSetPage(RowSet?crs,?int?start,?int?totalSize,?int?pageSize)?{ 

          352. ????????try{ 

          353. ????????????int?avaCount=0; 

          354. ????????????if?(crs!=null)?{ 

          355. ????????????????crs.beforeFirst(); 

          356. ????????????????if?(crs.next()){ 

          357. ????????????????????crs.last(); 

          358. ????????????????????avaCount?=?crs.getRow(); 

          359. ????????????????} 

          360. ????????????????crs.beforeFirst(); 

          361. ????????????} 

          362. ????????????rs?=?crs; 

          363. ????????????super.init(start,avaCount,totalSize,pageSize,rs); 

          364. ????????}catch(java.sql.SQLException?sqle){ 

          365. ????????????throw?new?RuntimeException(sqle.toString()); 

          366. ????????} 

          367. ????} 


          369. ????/**
          370. ?????*取分頁對象中的記錄數(shù)據(jù)
          371. ?????*/
          372. ????public?javax.sql.RowSet?getRowSet(){ 

          373. ????????return?rs; 

          374. ????} 



          377. } 





          382. ///////////////////////////////////
          383. //
          384. //??PagedStatement.java
          385. //??author:?evan_zhao@hotmail.com
          386. //
          387. ///////////////////////////////////

          389. package?page; 


          391. import?foo.DBUtil; 


          393. import?java.math.BigDecimal; 

          394. import?java.util.List; 

          395. import?java.util.Iterator; 

          396. import?java.util.Collections; 


          398. import?java.sql.Connection; 

          399. import?java.sql.SQLException; 

          400. import?java.sql.ResultSet; 

          401. import?java.sql.Statement; 

          402. import?java.sql.PreparedStatement; 

          403. import?java.sql.Timestamp; 

          404. import?javax.sql.RowSet; 


          406. /**
          407. ?*?<p>Title:?分頁查詢</p>
          408. ?*?<p>Description:?根據(jù)查詢語句和頁碼查詢出當(dāng)頁數(shù)據(jù)</p>
          409. ?*?<p>Copyright:?Copyright?(c)?2002</p>
          410. ?*?@author?evan_zhao@hotmail.com
          411. ?*?@version?1.0
          412. ?*/
          413. public?abstract?class?PagedStatement?{ 

          414. ????public?final?static?int?MAX_PAGE_SIZE?=?Page.MAX_PAGE_SIZE; 


          416. ????protected?String?countSQL,?querySQL; 

          417. ????protected?int?pageNo,pageSize,startIndex,totalCount; 

          418. ????protected?javax.sql.RowSet?rowSet; 

          419. ????protected?RowSetPage?rowSetPage; 


          421. ????private?List?boundParams; 


          423. ????/**
          424. ?????*?構(gòu)造一查詢出所有數(shù)據(jù)的PageStatement
          425. ?????*?@param?sql??query?sql
          426. ?????*/
          427. ????public?PagedStatement(String?sql){ 

          428. ????????this(sql,1,MAX_PAGE_SIZE); 

          429. ????} 



          432. ????/**
          433. ?????*?構(gòu)造一查詢出當(dāng)頁數(shù)據(jù)的PageStatement
          434. ?????*?@param?sql??query?sql
          435. ?????*?@param?pageNo??頁碼
          436. ?????*/
          437. ????public?PagedStatement(String?sql,?int?pageNo){ 

          438. ????????this(sql,?pageNo,?Page.DEFAULT_PAGE_SIZE); 

          439. ????} 


          441. ????/**
          442. ?????*?構(gòu)造一查詢出當(dāng)頁數(shù)據(jù)的PageStatement，并指定每頁顯示記錄條數(shù)
          443. ?????*?@param?sql?query?sql
          444. ?????*?@param?pageNo?頁碼
          445. ?????*?@param?pageSize?每頁容量
          446. ?????*/
          447. ????public?PagedStatement(String?sql,?int?pageNo,?int?pageSize){ 

          448. ????????this.pageNo?=?pageNo; 

          449. ????????this.pageSize?=?pageSize; 

          450. ????????this.startIndex?=?Page.getStartOfAnyPage(pageNo,?pageSize); 

          451. ????????this.boundParams?=?Collections.synchronizedList(new?java.util.LinkedList()); 


          453. ????????this.countSQL?=?"select?count(*)?from?(?"?+?sql?+")?"; 

          454. ????????this.querySQL?=?intiQuerySQL(sql,?this.startIndex,?pageSize); 

          455. ????} 



          458. ????/**
          459. ?????*生成查詢一頁數(shù)據(jù)的sql語句
          460. ?????*@param?sql?原查詢語句
          461. ?????*@startIndex?開始記錄位置
          462. ?????*@size?需要獲取的記錄數(shù)
          463. ?????*/
          464. ????protected?abstract??String?intiQuerySQL(String?sql,?int?startIndex,?int?size); 



          467. ????/**
          468. ?????*使用給出的對象設(shè)置指定參數(shù)的值
          469. ?????*@param?index?第一個參數(shù)為1，第二個為2，。。。
          470. ?????*@param?obj?包含參數(shù)值的對象
          471. ?????*/
          472. ????public?void?setObject(int?index,?Object?obj)?throws?SQLException{ 

          473. ????????BoundParam?bp?=?new?BoundParam(index,?obj); 

          474. ????????boundParams.remove(bp); 

          475. ????????boundParams.add(?bp); 

          476. ????} 


          478. ????/**
          479. ?????*使用給出的對象設(shè)置指定參數(shù)的值
          480. ?????*@param?index?第一個參數(shù)為1，第二個為2，。。。
          481. ?????*@param?obj?包含參數(shù)值的對象
          482. ?????*@param?targetSqlType?參數(shù)的數(shù)據(jù)庫類型
          483. ?????*/
          484. ????public?void?setObject(int?index,?Object?obj,?int?targetSqlType)?throws?SQLException{ 

          485. ????????BoundParam?bp?=?new?BoundParam(index,?obj,?targetSqlType); 

          486. ????????boundParams.remove(bp); 

          487. ????????boundParams.add(bp?); 

          488. ????} 


          490. ????/**
          491. ?????*使用給出的對象設(shè)置指定參數(shù)的值
          492. ?????*@param?index?第一個參數(shù)為1，第二個為2，。。。
          493. ?????*@param?obj?包含參數(shù)值的對象
          494. ?????*@param?targetSqlType?參數(shù)的數(shù)據(jù)庫類型(常量定義在java.sql.Types中)
          495. ?????*@param?scale?精度，小數(shù)點后的位數(shù)
          496. ?????*?（只對targetSqlType是Types.NUMBER或Types.DECIMAL有效，其它類型則忽略）
          497. ?????*/
          498. ????public?void?setObject(int?index,?Object?obj,?int?targetSqlType,?int?scale)?throws?SQLException{ 

          499. ????????BoundParam?bp?=?new?BoundParam(index,?obj,?targetSqlType,?scale)?; 

          500. ????????boundParams.remove(bp); 

          501. ????????boundParams.add(bp); 

          502. ????} 


          504. ????/**
          505. ?????*使用給出的字符串設(shè)置指定參數(shù)的值
          506. ?????*@param?index?第一個參數(shù)為1，第二個為2，。。。
          507. ?????*@param?str?包含參數(shù)值的字符串
          508. ?????*/
          509. ????public?void?setString(int?index,?String?str)throws?SQLException{ 

          510. ????????BoundParam?bp?=?new?BoundParam(index,?str)??; 

          511. ????????boundParams.remove(bp); 

          512. ????????boundParams.add(bp); 

          513. ????} 


          515. ????/**
          516. ?????*使用給出的字符串設(shè)置指定參數(shù)的值
          517. ?????*@param?index?第一個參數(shù)為1，第二個為2，。。。
          518. ?????*@param?timestamp?包含參數(shù)值的時間戳
          519. ?????*/
          520. ????public?void?setTimestamp(int?index,?Timestamp?timestamp)throws?SQLException{ 

          521. ????????BoundParam?bp?=?new?BoundParam(index,?timestamp)??; 

          522. ????????boundParams.remove(bp); 

          523. ????????boundParams.add(?bp?); 

          524. ????} 


          526. ????/**
          527. ?????*使用給出的整數(shù)設(shè)置指定參數(shù)的值
          528. ?????*@param?index?第一個參數(shù)為1，第二個為2，。。。
          529. ?????*@param?value?包含參數(shù)值的整數(shù)
          530. ?????*/
          531. ????public?void?setInt(int?index,?int?value)throws?SQLException{ 

          532. ????????BoundParam?bp?=??new?BoundParam(index,?new?Integer(value))??; 

          533. ????????boundParams.remove(bp); 

          534. ????????boundParams.add(?bp?); 

          535. ????} 


          537. ????/**
          538. ?????*使用給出的長整數(shù)設(shè)置指定參數(shù)的值
          539. ?????*@param?index?第一個參數(shù)為1，第二個為2，。。。
          540. ?????*@param?value?包含參數(shù)值的長整數(shù)
          541. ?????*/
          542. ????public?void?setLong(int?index,?long?value)throws?SQLException{ 

          543. ????????BoundParam?bp?=??new?BoundParam(index,?new?Long(value))??; 

          544. ????????boundParams.remove(bp); 

          545. ????????boundParams.add(?bp?); 

          546. ????} 


          548. ????/**
          549. ?????*使用給出的雙精度浮點數(shù)設(shè)置指定參數(shù)的值
          550. ?????*@param?index?第一個參數(shù)為1，第二個為2，。。。
          551. ?????*@param?value?包含參數(shù)值的雙精度浮點數(shù)
          552. ?????*/
          553. ????public?void?setDouble(int?index,?double?value)throws?SQLException{ 

          554. ????????BoundParam?bp?=??new?BoundParam(index,?new?Double(value))???; 

          555. ????????boundParams.remove(bp); 

          556. ????????boundParams.add(?bp); 

          557. ????} 


          559. ????/**
          560. ?????*使用給出的BigDecimal設(shè)置指定參數(shù)的值
          561. ?????*@param?index?第一個參數(shù)為1，第二個為2，。。。
          562. ?????*@param?bd?包含參數(shù)值的BigDecimal
          563. ?????*/
          564. ????public?void?setBigDecimal(int?index,?BigDecimal?bd)throws?SQLException{ 

          565. ????????BoundParam?bp?=???new?BoundParam(index,?bd?)???; 

          566. ????????boundParams.remove(bp); 

          567. ????????boundParams.add(?bp); 

          568. ????} 


          570. ????private??void?setParams(PreparedStatement?pst)?throws?SQLException{ 

          571. ????????if?(pst==null?||?this.boundParams==null?||?this.boundParams.size()==0?)?return?; 

          572. ????????BoundParam?param; 

          573. ????????for?(Iterator?itr?=?this.boundParams.iterator();itr.hasNext();){ 

          574. ????????????param?=?(BoundParam)?itr.next(); 

          575. ????????????if??(param==null)?continue; 

          576. ????????????if?(param.sqlType?==?java.sql.Types.OTHER){ 

          577. ????????????????pst.setObject(param.index,?param.value); 

          578. ????????????}else{ 

          579. ????????????????pst.setObject(param.index,?param.value,?param.sqlType,?param.scale); 

          580. ????????????} 

          581. ????????} 

          582. ????} 




          586. ????/**
          587. ?????*?執(zhí)行查詢?nèi)〉靡豁摂?shù)據(jù)，執(zhí)行結(jié)束后關(guān)閉數(shù)據(jù)庫連接
          588. ?????*?@return?RowSetPage
          589. ?????*?@throws?SQLException
          590. ?????*/
          591. ????public??RowSetPage?executeQuery()?throws?SQLException{ 

          592. ????????System.out.println("executeQueryUsingPreparedStatement"); 

          593. ????????Connection?conn?=?DBUtil.getConnection(); 

          594. ????????PreparedStatement?pst?=?null; 

          595. ????????ResultSet?rs?=?null; 

          596. ????????try{ 

          597. ????????????pst?=?conn.prepareStatement(this.countSQL); 

          598. ????????????setParams(pst); 

          599. ????????????rs?=pst.executeQuery(); 

          600. ????????????if?(rs.next()){ 

          601. ????????????????totalCount?=?rs.getInt(1); 

          602. ????????????}?else?{ 

          603. ????????????????totalCount?=?0; 

          604. ????????????} 


          606. ????????????rs.close(); 

          607. ????????????pst.close(); 


          609. ????????????if?(totalCount?<?1?)?return?RowSetPage.EMPTY_PAGE; 


          611. ????????????pst?=?conn.prepareStatement(this.querySQL); 

          612. ????????????System.out.println(querySQL); 

          613. ????????????pst.setFetchSize(this.pageSize); 

          614. ????????????setParams(pst); 

          615. ????????????rs?=pst.executeQuery(); 

          616. ????????????//rs.setFetchSize(pageSize);

          618. ????????????this.rowSet?=?populate(rs); 


          620. ????????????rs.close(); 

          621. ????????????rs?=?null; 

          622. ????????????pst.close(); 

          623. ????????????pst?=?null; 


          625. ????????????this.rowSetPage?=?new?RowSetPage(this.rowSet,startIndex,totalCount,pageSize); 

          626. ????????????return?this.rowSetPage; 

          627. ????????}catch(SQLException?sqle){ 

          628. ????????????//System.out.println("executeQuery?SQLException");
          629. ????????????sqle.printStackTrace(); 

          630. ????????????throw?sqle; 

          631. ????????}catch(Exception?e){ 

          632. ????????????e.printStackTrace(); 

          633. ????????????throw?new?RuntimeException(e.toString()); 

          634. ????????}finally{ 

          635. ????????????//System.out.println("executeQuery?finally");
          636. ????????????DBUtil.close(rs,?pst,?conn); 

          637. ????????} 

          638. ????} 


          640. ????/**
          641. ?????*將ResultSet數(shù)據(jù)填充進(jìn)CachedRowSet
          642. ?????*/
          643. ????protected?abstract?RowSet?populate(ResultSet?rs)?throws?SQLException; 


          645. ????/**
          646. ?????*取封裝成RowSet查詢結(jié)果
          647. ?????*@return?RowSet
          648. ?????*/
          649. ????public?javax.sql.RowSet?getRowSet(){ 

          650. ????????return?this.rowSet; 

          651. ????} 



          654. ????/**
          655. ?????*取封裝成RowSetPage的查詢結(jié)果
          656. ?????*@return?RowSetPage
          657. ?????*/
          658. ????public?RowSetPage?getRowSetPage()?{ 

          659. ????????return?this.rowSetPage; 

          660. ????} 




          664. ????/**
          665. ?????*關(guān)閉數(shù)據(jù)庫連接
          666. ?????*/
          667. ????public?void?close(){ 

          668. ????????//因為數(shù)據(jù)庫連接在查詢結(jié)束或發(fā)生異常時即關(guān)閉，此處不做任何事情
          669. ????????//留待擴(kuò)充。
          670. ????} 




          674. ????private?class?BoundParam?{ 

          675. ????????int?index; 

          676. ????????Object?value; 

          677. ????????int?sqlType; 

          678. ????????int?scale; 


          680. ????????public?BoundParam(int?index,?Object?value)?{ 

          681. ????????????this(index,?value,?java.sql.Types.OTHER); 

          682. ????????} 


          684. ????????public?BoundParam(int?index,?Object?value,?int?sqlType)?{ 

          685. ????????????this(index,?value,?sqlType,?0); 

          686. ????????} 


          688. ????????public?BoundParam(int?index,?Object?value,?int?sqlType,?int?scale)?{ 

          689. ????????????this.index?=?index; 

          690. ????????????this.value?=?value; 

          691. ????????????this.sqlType?=?sqlType; 

          692. ????????????this.scale?=?scale; 

          693. ????????} 


          695. ????????public?boolean?equals(Object?obj){ 

          696. ????????????if?(obj!=null?&&?this.getClass().isInstance(obj)){ 

          697. ????????????????BoundParam?bp?=?(BoundParam)obj; 

          698. ????????????????if?(this.index==bp.index)?return?true; 

          699. ????????????} 

          700. ????????????return?false; 

          701. ????????} 

          702. ????} 


          704. } 



          707. ///////////////////////////////////
          708. //
          709. //??PagedStatementOracleImpl.java
          710. //??author:?evan_zhao@hotmail.com
          711. //
          712. ///////////////////////////////////
          713. package?page; 

          714. import?java.sql.ResultSet; 

          715. import?java.sql.SQLException; 

          716. import?javax.sql.RowSet; 

          717. import?oracle.jdbc.rowset.OracleCachedRowSet; 


          719. /**
          720. ?*?<p>Title:?分頁查詢Oracle數(shù)據(jù)庫實現(xiàn)</p>
          721. ?*?<p>Copyright:?Copyright?(c)?2002</p>
          722. ?*?@author?evan_zhao@hotmail.com
          723. ?*?@version?1.0
          724. ?*/
          725. public?class?PagedStatementOracleImpl?extends?PagedStatement?{ 


          727. ????/**
          728. ?????*?構(gòu)造一查詢出所有數(shù)據(jù)的PageStatement
          729. ?????*?@param?sql??query?sql
          730. ?????*/
          731. ????public?PagedStatementOracleImpl(String?sql){ 

          732. ????????super(sql); 

          733. ????} 



          736. ????/**
          737. ?????*?構(gòu)造一查詢出當(dāng)頁數(shù)據(jù)的PageStatement
          738. ?????*?@param?sql??query?sql
          739. ?????*?@param?pageNo??頁碼
          740. ?????*/
          741. ????public?PagedStatementOracleImpl(String?sql,?int?pageNo){ 

          742. ????????super(sql,?pageNo); 

          743. ????} 


          745. ????/**
          746. ?????*?構(gòu)造一查詢出當(dāng)頁數(shù)據(jù)的PageStatement，并指定每頁顯示記錄條數(shù)
          747. ?????*?@param?sql?query?sql
          748. ?????*?@param?pageNo?頁碼
          749. ?????*?@param?pageSize?每頁容量
          750. ?????*/
          751. ????public?PagedStatementOracleImpl(String?sql,?int?pageNo,?int?pageSize){ 

          752. ????????super(sql,?pageNo,?pageSize); 

          753. ????} 



          756. ????/**
          757. ?????*生成查詢一頁數(shù)據(jù)的sql語句
          758. ?????*@param?sql?原查詢語句
          759. ?????*@startIndex?開始記錄位置
          760. ?????*@size?需要獲取的記錄數(shù)
          761. ?????*/
          762. ????protected?String?intiQuerySQL(String?sql,?int?startIndex,?int?size){ 

          763. ????????StringBuffer?querySQL?=?new?StringBuffer(); 

          764. ????????if?(size?!=?super.MAX_PAGE_SIZE)?{ 

          765. ????????????querySQL.append("select?*?from?(select?my_table.*,rownum?as?my_rownum?from(") 

          766. ????????????????????.append(??sql) 

          767. ????????????????????.append(")?my_table?where?rownum<").append(startIndex?+?size) 

          768. ????????????????????.append(")?where?my_rownum>=").append(startIndex); 

          769. ????????}?else?{ 

          770. ????????????querySQL.append("select?*?from?(select?my_table.*,rownum?as?my_rownum?from(") 

          771. ????????????????????.append(sql) 

          772. ????????????????????.append(")?my_table?") 

          773. ????????????????????.append(")?where?my_rownum>=").append(startIndex); 

          774. ????????} 

          775. ????????return?querySQL.toString(); 

          776. ????} 


          778. ????/**
          779. ?????*將ResultSet數(shù)據(jù)填充進(jìn)CachedRowSet
          780. ?????*/
          781. ????protected??RowSet?populate(ResultSet?rs)?throws?SQLException{ 

          782. ????????OracleCachedRowSet?ocrs?=?new?OracleCachedRowSet(); 

          783. ????????ocrs.populate(rs); 

          784. ????????return?ocrs; 

          785. ????} 


          787. } 


          相關(guān)連接：
          　　JSP頁面查詢顯示常用模式,介紹查詢結(jié)果集封裝的幾種常用模式。本程序使用了其中部分代碼
          　　RowSet規(guī)范原來是JDBC(TM)?2.0?Optional?Package的一部分，現(xiàn)在已經(jīng)并入JDBC3.0規(guī)范，并且將成為J2SE1.5的組成部分。
          　　關(guān)于RowSet的實現(xiàn)各個數(shù)據(jù)庫的jdbc?driver應(yīng)該都有提供,oracle實現(xiàn)可以到http://otn.oracle.com/software/tech/java/sqlj_jdbc/content.html下載(Additional?RowSet?support)
          　　Sun也提供了RowSet的參考實現(xiàn)，應(yīng)該可以支持大多數(shù)數(shù)據(jù)庫：http://java.sun.com/products/jdbc/download.html
          　　PetStore?是Sun關(guān)于J2EE設(shè)計模式的一個示例程序。 
	
          posted on 2006-03-13 22:27 rd2pm 閱讀(957) 評論(0)  編輯  收藏  
          

          







          
	    
    




          





          


          

	
          
		
          
				
		
	
		
          
		
		
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