1.首先定义了一个PageUtil的类，看了网上的很多教程，貌似都有一个这样的类，自己也定义了一个。在代码编写过程中发现这个类其实也没有那么大的作用，但是不去定义这个类，感觉好像缺少什么似得。(请高手解释下这个类的存在的意义。)
1 package com.util;
2
3 public class PageUtil {
4 private int totalRows; //总的记录数
5 private int curPage; //当前页码
6 private int pageSize; //每页记录数
7 private int totalPages;
8 public PageUtil(int totalRows, int curPage, int pageSize) {
9 super();
10 this.totalRows = totalRows;
11 this.curPage = curPage;
12 this.pageSize = pageSize;
13 }
14 public PageUtil(int totalRows, int pageSize) {
15 this.totalRows=totalRows;
16 this.pageSize=pageSize;
17 }
18
19 //总页数
20 public int getTotalPages() {
21 return totalRows%pageSize==0?totalRows/pageSize:totalRows/pageSize+1;
22 }
23 public int getTotalRows() {
24 return totalRows;
25 }
26 public void setTotalRows(int totalRows) {
27 this.totalRows = totalRows;
28 }
29 public int getCurPage() {
30 return curPage;
31 }
32 public void setCurPage(int curPage) {
33 this.curPage = curPage;
34 }
35 public int getPageSize() {
36 return pageSize;
37 }
38 public void setPageSize(int pageSize) {
39 this.pageSize = pageSize;
40 }
41 public void setTotalPages(int totalPages) {
42 this.totalPages = totalPages;
43 }
44
45 }
2. 自己根据所需的功能提供了一个QueryList的action类。
1 package com.action;
2
3 import java.util.List;
4
5 import javax.servlet.http.HttpSession;
6
7 import org.apache.struts2.ServletActionContext;
8
9 import com.bean.Student;
10 import com.daoImpl.DaoImpl;
11 import com.opensymphony.xwork2.ActionSupport;
12 import com.util.PageUtil;
13
14 public class QueryAll extends ActionSupport {
15 private final static int pageSize=8;
16 private DaoImpl daoImpl=new DaoImpl();
17 private PageUtil pageUtil;
18 private int rows;
19
20 private int curPage;
21 public void setCurPage(int curPage) {
22 this.curPage = curPage;
23 }
24
25 public String execute() throws Exception {
26 rows=daoImpl.getTotalRows();
27 pageUtil=new PageUtil(rows, pageSize);
28 if(curPage>pageUtil.getTotalPages()){
29 pageUtil.setCurPage(pageUtil.getTotalPages());
30 }
31 else if(curPage>0) {
32 pageUtil.setCurPage(curPage);
33 }else {
34 pageUtil.setCurPage(1);
35 }
36
37 //test
38 List<Student> studetnsInfo=daoImpl.queryList(pageUtil.getPageSize(), pageUtil.getCurPage());
39 System.out.println(studetnsInfo.size());
40
41 HttpSession session=ServletActionContext.getRequest().getSession();
42
43 session.setAttribute("list", studetnsInfo);
44 session.setAttribute("curPage", pageUtil.getCurPage());
45
46 return SUCCESS;
47 }
48
50 }
这里把前台所需的信息放在session里面，提供给前台使用。控制逻辑上当访问首页之前和尾页之后的页面的时候，自动定位到首页和尾页。
附上queryList()方法的代码。
1 public List<Student> queryList(int pageSize, int curPage) {
2 List<Student> list=new ArrayList<>();
3 Student stu;
4 String sql="select * from classa limit "+pageSize*(curPage-1)+", "+pageSize;
5 try {
6 con=JDBC_Connection.getConnection();
7 statement=con.createStatement();
8
9 res=statement.executeQuery(sql);
10 while(res.next()){
11 stu=new Student(res.getString(1), res.getString(2), res.getString(3), res.getDouble(4), res.getDouble(5));
12 list.add(stu);
13 }
14 } catch (SQLException e) {
15 e.printStackTrace();
16 }
17 try {
18 destory();
19 } catch (Exception e) {
20 e.printStackTrace();
21 }
22 return list;
23 }
3.前端页面自己不是太懂，随便写了展示jsp页面。
1 <body>
2 <%
3 int curPage=0;
4
5 if(session.getAttribute("curPage")!=null)
6 curPage=(int)session.getAttribute("curPage");
7 %>
8 <form action="queryAll" method="post">
9 <table width="98%" align="center" cellpadding="1" cellspacing="1" border="1">
10 <tr align="center">
11 <td width="5%">学号</td>
12 <td width="5%">姓名</td>
13 <td>学术贡献</td>
14 <td width="5%">scoreA</td>
15 <td width="5%">socreB</td>
16 </tr>
17 <s:iterator var="stu" value="#session.list" >
18 <tr>
19 <td>${stu.stuNo}</td>
20 <td>${stu.name}</td>
21 <td>${stu.detialInfo}</td>
22 <td>${stu.scoreA}</td>
23 <td>${stu.socreB}</td>
24 </tr>
25 </s:iterator>
26
27 </table>
28
29 <div align="right" style="color: red;">
30 <a href="queryAll?curPage=<%=curPage-1%>">上一页</a>/
31 <a href="queryAll?curPage=<%=curPage+1%>">下一页</a>
32 </div>
33
34
35 </form>
36
37 </body>
时间： 2024-08-27 18:55:49