一个通用的分页方法

一个通用的分页方法,不仅在数据库操作上分页了还在上层也做了分页.理解了这个就很容易理解其他框架的分页了.

java 代码

1.
2. import java.math. * ;
3.
4.
5.
6. public class Pager {
7.
8. private int totalRows; // 总行数

9.
10. private int pageSize=30 ; // 每页显示的行数

11.
12. private int currentPage; // 当前页号

13.
14. private int totalPages; // 总页数

15.
16. private int startRow; // 当前页在数据库中的起始行

17.
18.
19.
20. public Pager() {
21.
22.
23.
24. }
25.
26.
27.
28. public Pager( int _totalRows) {
29.
30. totalRows=_totalRows;
31.
32. totalPages=totalRows / pageSize;
33.
34. int mod=totalRows % pageSize;
35.
36. if (mod > 0 ) {
37.
38. totalPages ++ ;
39.
40. }
41.
42. currentPage=1 ;
43.
44. startRow=0 ;
45.
46. }
47.
48.
49.
50. public int getStartRow() {
51.
52. return startRow;
53.
54. }
55.
56. public int getTotalPages() {
57.
58. return totalPages;
59.
60. }
61.
62. public int getCurrentPage() {
63.
64. return currentPage;
65.
66. }
67.
68. public int getPageSize() {
69.
70. return pageSize;
71.
72. }
73.
74. public void setTotalRows( int totalRows) {
75.
76. this.totalRows = totalRows;
77.
78. }
79.
80. public void setStartRow( int startRow) {
81.
82. this.startRow = startRow;
83.
84. }
85.
86. public void setTotalPages( int totalPages) {
87.
88. this.totalPages = totalPages;
89.
90. }
91.
92. public void setCurrentPage( int currentPage) {
93.
94. this.currentPage = currentPage;
95.
96. }
97.
98. public void setPageSize( int pageSize) {
99.
100. this.pageSize = pageSize;
101.
102. }
103.
104. public int getTotalRows() {
105.
106. return totalRows;
107.
108. }
109.
110. public void first() {
111.
112. currentPage = 1 ;
113.
114. startRow = 0 ;
115.
116. }
117.
118. public void previous() {
119.
120. if (currentPage == 1 ) {
121.
122. return ;
123.
124. }
125.
126. currentPage -- ;
127.
128. startRow =(currentPage-1)*pageSize;
129.
130. }
131.
132. public void next() {
133.
134. if (currentPage<totalPages) {
135.
136. currentPage ++ ;
137.
138. }
139.
140. startRow=(currentPage-1)*pageSize;
141.
142. }
143.
144. public void last() {
145.
146. currentPage=totalPages;
147.
148. startRow=(currentPage-1 )*pageSize;
149.
150. }
151.
152. public void refresh(int _currentPage) {
153.
154. currentPage=_currentPage;
155.
156. if (currentPage>totalPages) {
157.
158. last();
159.
160. }
161.
162. }
163.
164. }
165.
166.
167.

操作pager的PagerService

java 代码

 

1.
2. package com.game.common;
3.
4.
5.
6. public class PagerService {
7.
8.
9.
10.
11.
12.
13.
14. public Pager getPager(String currentPage,String pagerMethod, int totalRows) {
15.
16. // 定义pager对象，用于传到页面
17.
18. Pager pager= new Pager(totalRows);
19.
20. // 如果当前页号为空，表示为首次查询该页
21.
22. // 如果不为空，则刷新pager对象，输入当前页号等信息
23.
24. if (currentPage!=null ) {
25.
26. pager.refresh(Integer.parseInt(currentPage));
27.
28. }
29.
30. // 获取当前执行的方法，首页，前一页，后一页，尾页。
31.
32. if (pagerMethod!=null ) {
33.
34. if (pagerMethod.equals("first")) {
35.
36. pager.first();
37.
38. } else if (pagerMethod.equals("previous")) {
39.
40. pager.previous();
41.
42. } else if (pagerMethod.equals("next")) {
43.
44. pager.next();
45.
46. } else if (pagerMethod.equals("last")) {
47.
48. pager.last();
49.
50. }
51.
52. }
53.
54. return pager;
55.
56. }
57.
58. }
59.
60.
61.

java 代码

 

1.
2. public class ProductsDaoImp extends HibernateDaoSupport implements ProductsDao {
3.
4.
5.
6. public int getRows() {
7.
8.
9.
10. String sql = " FROM Products ORDER BY gameNameCn " ;
11.
12. List list = this .getHibernateTemplate().find(sql);
13.
14. return list.size();
15.
16.
17.
18. }
19.
20.
21.
22. public void addProduct(Products pd) {
23.
24. this.getHibernateTemplate().save(pd);
25.
26.
27.
28. }
29.
30.
31.
32. public void deleteProduct(Products pd) {
33.
34. this.getHibernateTemplate().delete(pd);
35.
36.
37.
38. }
39.
40.
41.
42. public String getMaxId() {
43.
44. String sql="select max(gameId)+1 from Products" ;
45.
46. String noStr=null;
47.
48. List list=(List)this.getHibernateTemplate().find(sql);
49.
50. Iterator it=list.iterator();
51.
52. if(it.hasNext()){
53.
54. Object noInt=it.next();
55.
56. if(noInt==null){
57.
58. noStr="1";
59.
60. }else{
61.
62. noStr=noInt.toString();
63.
64. }
65.
66.
67.
68. }
69.
70. if(noStr.length()==1){
71.
72. noStr="000"+noStr;
73.
74. }else if(noStr.length()==2){
75.
76. noStr="00"+noStr;
77.
78. }else if(noStr.length()==2){
79.
80. noStr="0"+noStr;
81.
82. } else {
83.
84. noStr=noStr;
85.
86. }
87.
88.
89.
90. return noStr;
91.
92. }
93.
94.
95.
96. public List getProducts() {
97.
98. String hql="from products order by gameNameCn" ;
99.
100. this.getHibernateTemplate().find(hql);
101.
102. return null;
103.
104. }
105.
106.
107.
108. public List getProducts(final int pageSize, final int startRow) {
109.
110.
111.
112. return this.getHibernateTemplate().executeFind(new HibernateCallback(){
113.
114.
115.
116. public Object doInHibernate(Session session ) throws HibernateException, SQLException {
117.
118. Query query=session.createQuery("from products order by gameNameCn" );
119.
120. query.setFirstResult(startRow);
121.
122.
123.
124. query.setMaxResults(pageSize);
125.
126. return query.list();
127.
128. }
129.
130.
131.
132. });
133.
134.
135.
136. }
137.
138.
139.
140. public Products getProducts(int gameId) {
141.
142. return (Products)this.getHibernateTemplate().get(Products.class, gameId);
143.
144.
145.
146. }
147.
148.
149.
150. public int getRows(String fieldName, String value) {
151.
152.
153.
154. String sql = " FROM Products where " + fieldName + " like '% " + value + " %' " + " ORDER BY gameNameCn " ;
155.
156. List list = this .getHibernateTemplate().find(sql);
157.
158. return list.size();
159.
160. }
161.
162.
163.
164. public List queryProducts(String fieldName, String value) {
165.
166. String sql = "FROM Products where" + fieldName + "like'%" + value + "%' " + "ORDER BY gameNameCn" ;
167.
168.
169.
170. return this.getHibernateTemplate().find(sql);
171.
172. }
173.
174.
175.
176. public List queryProducts(String fieldName, String value, final int pageSize,
177.
178. final int startRow) {
179.
180. final String sql = " FROM Products where " + fieldName+ " like '% " + value + " %' " + " ORDER BY gameNameCn " ;
181.
182. return this.getHibernateTemplate().executeFind(new HibernateCallback(){
183.
184.
185.
186.
187.
188. public Object doInHibernate(Session session ) throws HibernateException, SQLException {
189.
190. Query query=session.createQuery(sql);
191.
192. query.setFirstResult(startRow);
193.
194.
195.
196. query.setMaxResults(pageSize);
197.
198. return query.list();
199.
200. }
201.
202.
203.
204. });
205.
206.
207.
208.
209.
210. }
211.
212.
213.
214. public void updateProductd(Products pd) {
215.
216. this.getHibernateTemplate().update(pd);
217.
218. }
219.
220.
221.
222. }