Java分页代码的独立实现

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

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 {  
      
        //结果集  
        private List 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 getList() {  
            return list;  
        }  
      
        public void setList(List 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 list=new ArrayList();  
            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 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