用JDBC實現數據庫分頁

文章轉自:http://blog.csdn.net/zxingchao2009/archive/2010/08/11/5805375.aspx

感謝!!!

 

一、所需參數

(1)當前頁數(currentPage)

就是來指明當前到底顯示到了第幾頁

(2)每頁顯示的數目(pageSize)

比如每頁顯示20條

(3)總記錄數(totalcount)

一般可由“select count(*) from table_name”獲得

(4)總頁數(totalPage)

totalPage=((totalCount+pageSize)-1)/pageSize

或者

if(totalCount%pageSize==0)

    totalPage=totalCount/pageSize;

else

    totalPage=totalCount/pageSize+1;

注意要確保總頁數至少爲1

if(totalPage==0)

    totalPage=1;

(5)JDBC ResultSet類定義結果集的方法rs.absolute(int n);

例如:rs.absolute((currentPage-1)*pageSize);

二、下面給出一個實例

1.建立用mysql數據庫及其表person

create database person;
use person;
create table person(id varchar(20),name varchar(20),age varchar(20),sex varchar(20));

2.編寫數據庫訪問公用類DBAccess.java

 

package com.zxc.struts.bean;  
  
import java.sql.Connection;  
import java.sql.DriverManager;  
import java.sql.SQLException;  
  
public class DBAccess {  
  
    /** 
     * @param args 
     */  
    public DBAccess(){  
    }  
    public static Connection getConnection(){  
        try {  
            Class.forName("com.mysql.jdbc.Driver");  
        } catch (ClassNotFoundException e) {  
            // TODO Auto-generated catch block  
            System.out.println("驅動程序未找到");  
            e.printStackTrace();  
        }  
        String url="jdbc:mysql://localhost:3306/person";  
        String user="root";  
        String password="123";  
        Connection conn=null;  
        try {  
            conn=DriverManager.getConnection(url, user, password);  
        } catch (SQLException e) {  
            // TODO Auto-generated catch block  
            System.out.println("數據庫連接出錯啦!");  
            e.printStackTrace();  
        }  
         System.out.println("Connection連接成功!");  
        return conn;  
    }  
    public static void main(String[] args) {  
        // TODO Auto-generated method stub  
        Connection connection=getConnection();  
    }  
  
}

 

3.編寫javabean

(1)Person.java

 

package com.zxc.struts.bean;  
  
public class Person {  
    private String id;  
    private String name;  
    private int age;  
    private String sex;  
    public String getId() {  
        return id;  
    }  
    public void setId(String id) {  
        this.id = id;  
    }  
    public String getName() {  
        return name;  
    }  
    public void setName(String name) {  
        this.name = name;  
    }  
    public int getAge() {  
        return age;  
    }  
    public void setAge(int age) {  
        this.age = age;  
    }  
    public String getSex() {  
        return sex;  
    }  
    public void setSex(String sex) {  
        this.sex = sex;  
    }  
  
}

(2)PageListData.java(封裝分頁參數以及頁面表現層函數的bean)

 

package com.zxc.struts.bean;  
  
import java.util.ArrayList;  
import java.util.Locale;  
  
import javax.servlet.http.HttpServletRequest;  
  
public class PageListData {  
    // 保存分頁數據對象  
    private ArrayList dataArray = null;  
  
    // 記錄總數  
    private int count = 0;  
  
    // 每頁顯示記錄數  
    private int pageSize = 0;  
  
    // 當前頁數  
    private int page = 1;  
  
    public PageListData() {  
        super();  
        newDataArray();  
    }  
  
    public ArrayList getDataArray() {  
        return dataArray;  
    }  
  
    public void setDataArray(ArrayList dataArray) {  
        this.dataArray = dataArray;  
    }  
    public void newDataArray() {  
        if (dataArray == null)  
            dataArray = new ArrayList();  
    }  
  
    public void setData(Object data) {  
        newDataArray();  
        getDataArray().add(data);  
    }  
  
    public void setData(int i, Object data) {  
        newDataArray();  
        getDataArray().add(i, data);  
    }  
  
    // 記錄總數  
    public int getCount() {  
        return count;  
    }  
  
    public void setCount(int count) {  
        this.count = count;  
    }  
  
    // 總頁數  
    public int getPageCount() {  
        if(count%pageSize==0){  
            return count/pageSize;  
        }else{  
            return count/pageSize+1;  
        }  
    }  
  
    // 每頁顯示 錄數  
    public int getPageSize() {  
        return pageSize;  
    }  
  
    public void setPageSize(int pageSize) {  
        this.pageSize = pageSize;  
    }  
  
    // 當前頁數  
    public int getPage() {  
        return page;  
    }  
  
    public void setPage(int page) {  
        this.page = page;  
    }  
    /**分頁表現層 
     * 封裝分頁欄函數  必需被包含在某個Form之中 
     * @param request  HttpServletRequest 
     * @return String  pages  當前頁號  pageSize  每頁顯示行數 
     */  
    public String getFooter(HttpServletRequest request) {  
        String previous = "上一頁";  
        String next ="下一頁";  
  
        StringBuffer pageStr = new StringBuffer("");  
        pageStr.append("<center><p class='pages'>");  
        int nTotalPages = getPageCount(); //總頁數  
        int nCurrentPage = getPage();   //當前頁  
        int nPrevPage = getPage() - 1;   //上一頁  
        int nNextPage = getPage() + 1;   //下一頁  
        int first = 0;  
        int last = 0;  
        if (nCurrentPage > 1){  
            pageStr.append("<a onclick='document.getElementById(/"pages/").value=" + nPrevPage + ";document.getElementById(/"pages/").form.submit();' class='prevpage' style="cursor: pointer;" mce_style="cursor: pointer;" ><strong>" + previous +"</strong></a>  ");  
        }  
          
        for (int i = 1; i <= nTotalPages; i++) {  
            if (i == nCurrentPage){  
                pageStr.append("<span style="padding:1px 8px 1px 8px;color:#fff;text-decoration:none!important;background:url(./pgback.png) no-repeat center center;" mce_style="padding:1px 8px 1px 8px;color:#fff;text-decoration:none!important;background:url(pgback.png) no-repeat center center;">" + i + "</span>  ");  
            } else {  
                if(nCurrentPage == 1 && (i == 2 || i==3)) {  
                    pageStr.append("<a id='Pagelist' onclick='document.getElementById(/"pages/").value="+ i +";document.getElementById(/"pages/").form.submit();' style="cursor: pointer;" mce_style="cursor: pointer;">" + i + "</a>   ");  
                } else if (i != 1 && nCurrentPage >= 5 && i < nCurrentPage) {  
                    if(first == 0) {  
                        pageStr.append("<span class='pgempty'>...</span>");  
                        first = 1;  
                    }  
                    if(nCurrentPage == nTotalPages && i == nTotalPages - 1) {  
                        pageStr.append("<a id='Pagelist' onclick='document.getElementById(/"pages/").value="+ i +";document.getElementById(/"pages/").form.submit();' style="cursor: pointer;" mce_style="cursor: pointer;">" + i + "</a>   ");  
                    }  
                } else if( i <= nTotalPages && nCurrentPage <= nTotalPages - 4 && i > (nCurrentPage + 1)) {  
                    if(last == 0) {  
                        pageStr.append("<span class='pgempty'>...</span>");  
                        last = 1;  
                    }  
                    if(i==nTotalPages){  
                        pageStr.append("<a id='Pagelist' onclick='document.getElementById(/"pages/").value="+ i +";document.getElementById(/"pages/").form.submit();' style="cursor: pointer;" mce_style="cursor: pointer;">" + i + "</a>   ");  
                    }  
                } else {  
                    pageStr.append("<a id='Pagelist' onclick='document.getElementById(/"pages/").value="+ i +";document.getElementById(/"pages/").form.submit();' style="cursor: pointer;" mce_style="cursor: pointer;">" + i + "</a>   ");  
                }  
                  
            }  
        }  
        if (nCurrentPage < nTotalPages)  
        {  
            pageStr.append("<a class='nextpage'style='cursor: pointer;' onclick='document.getElementById(/"pages/").value=" + nNextPage + ";document.getElementById(/"pages/").form.submit();'><strong>" + next +"</strong></a></center>");  
        }  
        pageStr.append("</p>");  
        pageStr.append("<input type='hidden' value='" + nCurrentPage  
                        + "' name='pages' id='pages' />");  
        pageStr.append("<input type='hidden' value='" + pageSize  
                + "' name='pageSize' id='pageSize' />");  
        return pageStr.toString();  
    }  
//  public String getPager(HttpServletRequest request) {  
//      String previous = "previous";  
//      String next = "next";  
//    
//      StringBuffer pageStr = new StringBuffer("");  
//      pageStr.append("<div id='pager' class='pager'>");  
//      pageStr.append("<div id='pagenumber' class='pagedisplay pages'></div>");  
//      pageStr.append("<input class='pagesize' type='hidden' value='"+ pageSize  
//                              + "' name='pageSize' id='pageSize' />");  
//      pageStr.append("<input type='hidden' value='"+ previous  
//              + "' name='labpre' id='labpre' />");  
//      pageStr.append("<input type='hidden' value='"+ next  
//              + "' name='labnext' id='labnext' />");  
//      pageStr.append("</div>");  
//    
//      return pageStr.toString();  
//  }  
}

4.編寫數據訪問層ManagerPerson.java

 

package com.zxc.struts.bean;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.zxc.struts.bean.DBAccess;
public class ManagerPerson {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        //往數據庫插入100條數據
        List list1=new ArrayList();
        for (int i = 1; i < 101; i++) {
            Person person = new Person();
            person.setId(String.valueOf(i));
            person.setName("A");
            person.setAge(i + 20);
            person.setSex("man");
            list1.add(person);
        }
        insertData(list1);
    }
    //返回的map中包含所需的結果集和總的記錄數
    public static Map getList(int pageSize,int currentPage){
        String sql="select * from person";
        Connection conn=null;
        PreparedStatement ps=null;
        ResultSet rs=null;
        Map result=null;
        List list=null;
        Person p=null;
        try{
            conn=DBAccess.getConnection();
            result=new HashMap();
            list=new ArrayList();
            ps=conn.prepareStatement(sql);
            rs=ps.executeQuery();
            if((currentPage-1)*pageSize!=0)
                rs.absolute((currentPage-1)*pageSize);
            int i=0;
            while(rs.next()&&i++<pageSize){
                p=new Person();
                p.setId(rs.getString("id"));
                p.setName(rs.getString("name"));
                p.setSex(rs.getString("sex"));
                p.setAge(Integer.parseInt(rs.getString("age")));
                list.add(p);

            }
            result.put("list", list);
            rs.close();
            ps.close();
            sql="select count(*) from person";
            ps=conn.prepareStatement(sql);
            rs=ps.executeQuery(sql);
            if(rs.next()){
                result.put("tatalcount", rs.getInt(1));
            }
            rs.close();
            ps.close();
            conn.close();
        }catch(Exception e){
            e.printStackTrace();
        }
        return result;
    }
    //將list中的數據插入到數據庫中
    public static void insertData(List list){
        String sql="insert into person values(?,?,?,?)";
        Connection conn=DBAccess.getConnection();
        PreparedStatement ps=null;
        ResultSet rs=null;
        int n=0;
        for(int i=0;i<list.size();i++){
            try{
                Person p=(Person)list.get(i);
                ps=conn.prepareStatement(sql);
                ps.setString(1, p.getId());
                ps.setString(2, p.getName());
                ps.setString(3, String.valueOf(p.getAge()));
                ps.setString(4,p.getSex());
                n=ps.executeUpdate();
                if(n==1){
                    System.out.println("插入一條數據成功！");
                }else{
                    System.out.println("插入一條數據失敗!");
                }
            }catch(Exception e){
                e.printStackTrace();
            }
        }
        try{
            ps.close();
            conn.close();
        }catch(SQLException e){
            e.printStackTrace();
        }
    }

}

 

5.編寫業務邏輯層PaginationAction.java

 

/*
 * Generated by MyEclipse Struts
 * Template path: templates/java/JavaClass.vtl
 */
package com.zxc.struts.action;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;

import com.zxc.struts.bean.ManagerPerson;
import com.zxc.struts.bean.PageListData;
import com.zxc.struts.bean.Person;


/**
 * MyEclipse Struts
 * Creation date: 08-10-2010
 *
 * XDoclet definition:
 * @struts.action validate="true"
 */
public class PaginationAction extends Action {
    /*
     * Generated Methods
     */

    /**
     * Method execute
     * @param mapping
     * @param form
     * @param request
     * @param response
     * @return ActionForward
     */
    public ActionForward execute(ActionMapping mapping, ActionForm form,
            HttpServletRequest request, HttpServletResponse response) {
        // TODO Auto-generated method stub
        int currPage = request.getParameter("pages")==null?1:Integer.parseInt(request.getParameter("pages"));
        int pageSize = request.getParameter("pageSize")==null?5:Integer.parseInt(request.getParameter("pageSize"));
        Map map=ManagerPerson.getList(pageSize, currPage);
        PageListData listdata=new PageListData();
        listdata.setCount(Integer.parseInt(map.get("tatalcount")==null?"":map.get("tatalcount").toString()));
        listdata.setPage(currPage);
        listdata.setPageSize(pageSize);
        listdata.setDataArray((ArrayList)map.get("list"));
        request.setAttribute("footer", listdata.getFooter(request));
        System.out.println(listdata.getFooter(request));
        request.setAttribute("listdata", listdata);
        return mapping.findForward("success");
    }
}

 

6.配置struts-config.properties

 

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts-config PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 1.3//EN" "http://struts.apache.org/dtds/struts-config_1_3.dtd">

<struts-config>
  <form-beans />
  <global-exceptions />
  <global-forwards />
  <action-mappings >
     <action
      path="/pagination"
      type="com.zxc.struts.action.PaginationAction"
      cancellable="true" >
      <forward name="success" path="/pagesort.jsp"/>
      </action>
  </action-mappings>

  <message-resources parameter="com.zxc.struts.ApplicationResources"/>
</struts-config>

 

7.表現層頁面

(1)index.jsp

 

<%@ page language="java" pageEncoding="UTF-8"%>
<%
    String path = request.getContextPath();
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
    <body>
    <form>
        <a href="<%=path%>/pagination.do">JDBC分頁練習</a>
        </form>
    </body>
</html>

 

(2)pagesort.jsp

 

<%@ page language="java" isELIgnored="false" pageEncoding="utf-8"%>
<%@ taglib uri="/WEB-INF/c.tld" prefix="c"%>
<%
    String path = request.getContextPath();
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<link href="<%=path%>/tefort.css" type="text/css" rel="stylesheet"/>
<link href="<%=path%>/template01.css" type="text/css" rel="stylesheet"/>
</head>
    <body>
        <form action="<%=path%>/pagination.do" method="post">

            <table>
                <thead>
                    <tr>
                        <td style="width:20%">
                            id
                        </td>
                        <td style="width:30">
                            name
                        </td>
                        <td style="width:25%">
                            sex
                        </td>
                        <td style="width:25%">
                            age
                        </td>
                    </tr>
                </thead>
                <tbody>
                    <c:if test="${not empty listdata}">
                        <c:forEach items="${listdata.dataArray}" var="data">
                        <tr>
                        <td>${data.id}</td>
                        <td>${data.name}</td>
                        <td>${data.age}</td>
                        <td>${data.sex }</td>
                        </tr>
                        </c:forEach>
                    </c:if>
                </tbody>
            </table>
            ${footer}
        </form>
    </body>
</html>

 

8.運行結果

在瀏覽器輸入http://localhost:8080/j2eePractice