Jsp+struts分页显示源码

主要有三个文件：show.jsp、ShowAction.java、PageInformation.java

环境是:JDK1.6+mysql5.0+jboss4.0+struts 2.0.11

还需完善的地方：如果没有前一页、后一页，直接把这个链接在页面上屏蔽掉
因为不想在Action里面有太多的链接数据库的代码，所以另外搞了一个PageInformation类，来完成数据库查询工作。

具体代码如下：
package com.ClockWise.ray.jsp;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
/*
* 此类用来完成数据库操作
* */
public class PageInformation {
             private int pageSize;//每一页包含的条目个数
             private int totalRows;//一共有多少行
             private int totalPages;//一共有多少页
             private int currentPage=1;//初始化当前页为第一页
             private boolean hasPrevious = false;//是否有前页，尚未使用，有待完善
             private boolean hasNext = false;//是否有后页，尚未使用，有待完善
             private ArrayList<User> list = new ArrayList<User>();//存放结果的列表
             private DatabaseGeneralServices dgs;//自己写的获得connection的类，可以自己实现
             private Connection conn;          
             private PreparedStatement ps;
             private ResultSet rs;

             public PageInformation(){
             dgs = DatabaseGeneralServices.getInstance();
             pageSize = 20;//每页设置为20条
             totalRows = initRowCount();//得到总行数，比较粗犷，不知有什么灵巧的方法，比如select count(*)...
             totalPages =((totalRows+pageSize)-1)/pageSize;//获得总页数
             initList(1);
               }
            /*
             * 每次查询只取20条，封装为一个列表，返回。参数是当前页号，在构造函数中默认为第一页
      * */
             private void initList(int currentPage){
                 list.removeAll(list);
             conn = dgs.getConnection();
             try{
                        ps = conn.prepareStatement("Select * FROM jsptest LIMIT ?,20");
                        int temp = (currentPage-1)*20;
                        ps.setInt(1, temp);
                        rs = ps.executeQuery();
                        while (rs.next()){
                                 User user = new User();
                                 user.setId(rs.getString(1));
                                 user.setName(rs.getString(2));
                                 list.add(user);
                        }
             }catch(SQLException e){
                        e.printStackTrace();
             }finally{
                        dgs.closeConnection(rs, ps, conn);
             }
             }
             //粗犷的得到行数
             private int initRowCount(){
             conn = dgs.getConnection();
             try{
             ps = conn.prepareStatement("Select * FROM jsptest");
             rs = ps.executeQuery();
             rs.last();
             int result = rs.getRow();
             rs.first();
             return result;
             }catch(SQLException e){
                        e.printStackTrace();
             }finally{
                        dgs.closeConnection(rs, ps, conn);
             }
             return 0;
             }

             //页面调数据的时候，重新发出查询，初始化结果列表
                   public ArrayList<User> getList(int cp) {
                            initList(cp);
                            ArrayList<User> temp = new ArrayList<User>();
                            for(int i =0;i<20;i++){
                                     temp.add(list.get(i));
                            }
                            return temp;
                   }
        //other setters and getters
                   ……
} 

紧接着是Action代码
package com.ClockWise.ray.jsp;
import java.util.ArrayList;
import com.opensymphony.xwork2.ActionSupport;
public class ShowAction extends ActionSupport {
         private int totalPages;
         private boolean hasPre;
         private boolean hasNext;
         private int currentPage=1;
         private ArrayList<User> list;
         //以上几个和PageInformation里面的一一对应
         private String username ="ray";
         private ArrayList list2= new ArrayList();//这个list用来存放下面的页码起始位置
         private PageInformation pi;

         public String execute(){
                   init(currentPage);
                   return SUCCESS;
         }

         private void init(int currentPage){
                   pi = new PageInformation();
                   this.setTotalPages(pi.getTotalPages());
                   this.setHasPre(pi.isHasPrevious());
                   this.setHasNext(pi.isHasNext());
                   this.setList(pi.getList(currentPage));

                   for(int i =currentPage;i<=currentPage+20;i++){
                            Current c = new Current();
                            c.setCurrentPage(i);
                            list2.add(c);
                   }
         }

        public ArrayList<User> getList() {
                   this.setList(pi.getList(currentPage));
                   return list;
         }
//other setters and getters
…….
} 

最后是JSP代码
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<s:form action="ShowAction" method="GET">
   <h1>Welcome <s:property value="username"/></h1><BR>
   <h1>CurrentPage <s:property value="currentPage"/></h1>
   <!--show items of this page-->
   <s:iterator value="list" status="status">
        <s:property value="id"/>
        <s:property value="name"/>
        <BR>
   </s:iterator>

   <!--define the url of the previous page and next page-->
     <s:url id="url_pre" value="ShowAction.action">
         <s:param name="currentPage" value="currentPage-1"></s:param>
     </s:url>
     <s:url id="url_next" value="ShowAction.action">
         <s:param name="currentPage" value="currentPage+1"></s:param>
     </s:url> 

   <!-- use url defined above -->    
   <s:a href="%{url_pre}">Pre</s:a>
   <s:iterator value="list2" status="status">
      <s:url id="url" value="ShowAction.action">
      <!-- pass the currentPage parameter -->
         <s:param name="currentPage" value="currentPage"></s:param>
      </s:url>
      <s:a href="%{url}"><s:property value="currentPage"/> </s:a>
   </s:iterator>
   <s:a href="%{url_next}">Next</s:a>
</s:form>  
</body>
</html>