Java分页代码的实现

在项目中，分页是一个项目中必不可少的，它可以防止我们从数据库中进行大量数据查询时速度变慢，提高我们的查询效率

http://www.open-open.com/lib/view/open1346772322162.html

1、定义分页模型：PageModel

package com.common.page;  
  
import java.util.List;  
  
/** 
 * 封装分页信息 
 * @author Administrator 
 * 
 */  
public class PageModel<E> {  
  
    //结果集  
    private List<E> list;  
      
    //查询记录数  
    private int totalRecords;  
      
    //每页多少条数据  
    private int pageSize;  
      
    //第几页  
    private int pageNo;  
      
    /** 
     * 总页数 
     * @return 
     */  
    public int getTotalPages() {  
        return (totalRecords + pageSize - 1) / pageSize;  
    }  
      
    /** 
     * 取得首页 
     * @return 
     */  
    public int getTopPageNo() {  
        return 1;  
    }  
      
    /** 
     * 上一页 
     * @return 
     */  
    public int getPreviousPageNo() {  
        if (pageNo <= 1) {  
            return 1;  
        }  
        return pageNo - 1;  
    }  
      
    /** 
     * 下一页 
     * @return 
     */  
    public int getNextPageNo() {  
        if (pageNo >= getBottomPageNo()) {  
            return getBottomPageNo();  
        }  
        return pageNo + 1;    
    }  
      
    /** 
     * 取得尾页 
     * @return 
     */  
    public int getBottomPageNo() {  
        return getTotalPages();  
    }  
      
    public List<E> getList() {  
        return list;  
    }  
  
    public void setList(List<E> list) {  
        this.list = list;  
    }  
  
    public int getTotalRecords() {  
        return totalRecords;  
    }  
  
    public void setTotalRecords(int totalRecords) {  
        this.totalRecords = totalRecords;  
    }  
  
    public int getPageSize() {  
        return pageSize;  
    }  
  
    public void setPageSize(int pageSize) {  
        this.pageSize = pageSize;  
    }  
  
    public int getPageNo() {  
        return pageNo;  
    }  
  
    public void setPageNo(int pageNo) {  
        this.pageNo = pageNo;  
    }  
}  

2、分页测试：在MySQL中建立admin表，里面有字段id、name、password

3、简历Admin的实体bean类：

package com.common.page;  
  
public class Admin {  
    private int id;  
    private String name;  
    private String password;  
    public int getId() {  
        return id;  
    }  
    public void setId(int id) {  
        this.id = id;  
    }  
    public String getName() {  
        return name;  
    }  
    public void setName(String name) {  
        this.name = name;  
    }  
    public String getPassword() {  
        return password;  
    }  
    public void setPassword(String password) {  
        this.password = password;  
    }  
  
}  

4、测试调用：

package com.common.page;  
  
import java.sql.Connection;  
import java.sql.PreparedStatement;  
import java.sql.ResultSet;  
import java.sql.SQLException;  
import java.util.ArrayList;  
import java.util.List;  
  
import com.common.db.DbUtil;  
  
public class Client {  
    public static PageModel findAdmins(int pageNo,int pageSize){  
        Connection conn=DbUtil.getConnection();  
        String sql="select * from admin limit ?,?";  
        PageModel pageModel=null;  
        PreparedStatement pstm=null;  
        ResultSet rs=null;  
        Admin admin=null;  
        List<Admin> list=new ArrayList<Admin>();  
        try {  
            pstm=conn.prepareStatement(sql);  
            pstm.setInt(1, (pageNo-1)*pageSize);  
            pstm.setInt(2, pageNo*pageSize);  
            rs=pstm.executeQuery();;  
            while(rs.next()){  
                admin=new Admin();  
                admin.setId(rs.getInt("a_id"));  
                admin.setName(rs.getString("a_name"));  
                admin.setPassword(rs.getString("a_pwd"));  
                list.add(admin);  
            }  
            ResultSet rs2=pstm.executeQuery("select count(*) from admin");  
            int total=0;  
            if(rs2.next()){  
                total=rs2.getInt(1);  
            }  
            pageModel=new PageModel();  
            pageModel.setPageNo(pageNo);  
            pageModel.setPageSize(pageSize);  
            pageModel.setTotalRecords(total);  
            pageModel.setList(list);  
        } catch (SQLException e) {  
            e.printStackTrace();  
        }finally{  
            DbUtil.close(conn);  
            DbUtil.close(pstm);  
            DbUtil.close(rs);  
        }  
        return pageModel;  
    }  
      
    public static void main(String[] args) {  
        PageModel pageModel=Client.findAdmins(2,4);  
        List<Admin> list=pageModel.getList();  
        for(Admin a:list){  
            System.out.print("ID:"+a.getId()+",用户名:"+a.getName()+",密码:"+a.getPassword());  
            System.out.println();  
        }  
        System.out.print("当前页:"+pageModel.getPageNo()+" ");  
        System.out.print("共"+pageModel.getTotalPages()+"页  ");  
        System.out.print("首页:"+pageModel.getTopPageNo()+" ");  
        System.out.print("上一页:"+pageModel.getPreviousPageNo()+" ");  
        System.out.print("下一页:"+pageModel.getNextPageNo()+" ");  
        System.out.print("尾页:"+pageModel.getBottomPageNo()+" ");  
        System.out.print("共"+pageModel.getTotalRecords()+"条记录");  
        System.out.println();  
    }  
  
}  

这样分页效果就实现了，我们要实现分页效果，只要传入相应的参数和相应的数据库执行语句即可实现，希望大家能灵活运用。

转自：http://blog.csdn.net/harderxin/article/details/7731313