java实现对数据库的分页

package util;

 

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.List;

 

/**

 * @author Hongyu

 *

 * @param <T>

 */

publicclass Pagination<T> {

    // 当前页

    privateIntegernowPage;

    // 页面要显示信息条数

    privateIntegerpageSize;

    // 根据页面显示的条数计算总页数

    privateIntegercountPage;

    // 根据传入的数据库查询数据库中的信息的条数

    privateIntegertotal;

    // 向数据库查询时的开始的下标

    privateIntegerstartIndex;

    // 向数据库查询时的查询条数

    privateIntegerendIndex;

 

 

    // 将查询到的数据存放到这里

    private List<T> rows;

 

    publicPagination(IntegernowPage, IntegerpageSize, String tableName) {

        // 赋值

        this.nowPage = nowPage;

        this.pageSize = pageSize;

 

        // 判断当前页是否合法

        if (this.nowPage < 1) {

            this.nowPage = 1;

        }

 

        // 向数据库发送查询,查询出指定表格的数据的总数

        this.total = this.getCountSize(tableName);

        // 计算总页数

        this.countPage = this.total % this.pageSize == 0 ? this.total

                / this.pageSize : this.total / this.pageSize + 1;

 

        if (this.nowPage > this.countPage) {

            this.nowPage = this.countPage;

        }

 

        //System.out.println("pagenation中的nowPage=========="+ this.nowPage);

        // 计算出开始的记录下标,和每页要显示的条数

 

        if (this.nowPage == 0) {

            this.startIndex = this.nowPage * this.pageSize;

            this.endIndex = this.pageSize;

        }else{

            this.startIndex = (this.nowPage - 1) * this.pageSize;

            this.endIndex = this.pageSize;

        }

 

        /*System.out.println(this.startIndex + "======pagenation中的开始和结束========"

                + this.endIndex+"====================总页数"+countPage);

*/

    }

 

    // 根据提供的表名向数据库发送请求,计算指定数据表中的数据总条数

    publicInteger getCountSize(String tableName) {

        intcountRecord = 0;

        String sql = "select count(*) as c from " + tableName;

        Connectionconn = JdbcUtil.getConn();

        PreparedStatement pstmt = null;

        ResultSet rs = null;

        try {

            pstmt = conn.prepareStatement(sql);

            rs = pstmt.executeQuery();

            if (rs.next()) {

                countRecord = rs.getInt("c");

            }

        } catch (SQLException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        } finally {

            JdbcUtil.release(rs, pstmt);

        }

        returncountRecord;

    }

 

    publicList<T> getRows() {

        returnrows;

    }

 

    publicvoid setRows(List<T> rows) {

        this.rows= rows;

    }

 

    publicInteger getStartIndex() {

        returnstartIndex;

    }

 

    publicInteger getEndIndex() {

        returnendIndex;

    }

 

    publicInteger getTotal() {

        returntotal;

    }

     

 

 

}