hibernate和struts实现分页

仓促把功能进行实现一下  类与类之间也没有进行MVC式分开  重要的是逻辑 记录一下 希望其中的些许代码逻辑对你有用

 

TUserDaoImpl---dao层的实现
package com.pers.hoobey;

import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.Transaction;

import java.util.List;

/**
 * Created by hoobey on 2017/9/7.
 */
public class TUserDaoImpl implements TUserDao {
    @Override
    public TUser busOper(TUser bean, int oper) {
        Session s = HibernateSessionFactory.getSession();
        Transaction tx = s.getTransaction();
        TUser user = new TUser();
        try {
            tx.begin();
            user = bean;
//evict变为脱管状态,脱管对象通过session的save,update,saveOrUpdate,lock等方法变回持久化对象
            s.evict(bean);
            if (oper == -1) {
                s.delete(bean);
            } else if (oper == 0) {
                s.update(bean);
            } else if (oper == 1) {
                s.save(bean);
            } else {
                user = (TUser) s.get(TUser.class, bean.getId());
            }
            tx.commit();
        } catch (Exception ex) {
            ex.printStackTrace();
            tx.rollback();//事务回滚
            return null;
        }
        s.evict(bean);
        s.close();
        return user;
    }

    /**
     * 使用hibernate提供的分页功能，得到分页显示的数据
     * select * from t_user limit 0,3;
     * 0=offset
     * 3=pageSize
     */
    @SuppressWarnings("unchecked")
    @Override
    public List<TUser> queryByPage(String hql, int offset, int pageSize) {
        Session session = HibernateSessionFactory.getSession();
        Transaction tx = null;
        List<TUser> list = null;

        try {
            tx = session.beginTransaction();

            Query query = session.createQuery(hql).setFirstResult(offset).setMaxResults(pageSize);

            list = query.list();

            tx.commit();

        } catch (Exception e) {
            if (tx != null) {
                tx.rollback();
            }
            e.printStackTrace();
        } finally {
            HibernateSessionFactory.closeSession();
        }
        return list;
    }


    /**
     * 通过hql语句得到数据库中记录总数
     */
    @Override
    public int getAllRowCount(String hql) {
        Session session = HibernateSessionFactory.getSession();
        Transaction tx = null;
        int allRows = 0;
        try {
            tx = session.beginTransaction();

            Query query = session.createQuery(hql);

            allRows = query.list().size();

            tx.commit();

        } catch (Exception e) {
            if (tx != null) {
                tx.rollback();
            }

            e.printStackTrace();
        } finally {
            HibernateSessionFactory.closeSession();
        }

        return allRows;
    }
}

2.PageBean--每一页显示的信息内容
package com.pers.hoobey;
import java.util.List;
/**
 * Created by hoobey on 2017/9/7.
 * (每一页所需要的内容都存放在这个PageBean里面)，里面用来存放网页每一页显示的内容
 */
public class PageBean {
    private List<TUser> list; //通过hql从数据库分页查询出来的list集合

    private int allRows; //总记录数

    private int totalPage; //总页数

    private int currentPage; //当前页
    /**
     * 得到总页数
     *
     * @param pageSize 每页记录数
     * @param allRows  总记录数
     * @return 总页数
     */
    public int getTotalPages(int pageSize, int allRows) {
        int totalPage = (allRows % pageSize == 0) ? (allRows / pageSize) : (allRows / pageSize) + 1;

        return totalPage;
    }

    /**
     * 得到当前开始记录号
     *
     * @param pageSize    每页记录数
     * @param currentPage 当前页
     * @return
     */
    public int getCurrentPageOffset(int pageSize, int currentPage) {
        int offset = pageSize * (currentPage - 1);

        return offset;
    }

    /**
     * 得到当前页， 如果为0 则开始第一页，否则为当前页
     *
     * @param page
     * @return
     */
    public int getCurPage(int page) {
        int currentPage = (page == 0) ? 1 : page;

        return currentPage;
    }

    public List<TUser> getList() {
        return list;
    }

    public void setList(List<TUser> list) {
        this.list = list;
    }

    public int getAllRows() {
        return allRows;
    }

    public void setAllRows(int allRows) {
        this.allRows = allRows;
    }

    public int getTotalPage() {
        return totalPage;
    }

    public void setTotalPage(int totalPage) {
        this.totalPage = totalPage;
    }

    public int getCurrentPage() {
        return currentPage;
    }

    public void setCurrentPage(int currentPage) {
        this.currentPage = currentPage;
    }

}

3.TUserServiceImpl---service层实现
package com.pers.hoobey;

import java.util.Iterator;
import java.util.List;

/**
 * Created by hoobey on 2017/9/7.
 */
public class TUserServiceImpl implements TUserService {
        private TUserDaoImpl tUserDaoImpl = new TUserDaoImpl();

    /**
     * pageSize为每页显示的记录数
     * page为当前显示的页数 从0开始
     */
    @Override
    public PageBean getPageBean(int pageSize, int page) {
        PageBean pageBean = new PageBean();

        String hql = "from TUser limit ";

        int allRows = tUserDaoImpl.getAllRowCount(hql);//总记录数

        int totalPage = pageBean.getTotalPages(pageSize, allRows);//总页数

        int currentPage = pageBean.getCurPage(page);//当前页

        int offset = pageBean.getCurrentPageOffset(pageSize, currentPage);//当前页是  从1开始 要减去1  默认从0开始

//此处就隐含了分页查询  比对 select * from user limit "+(pageNo-1)*pageSize+","+pageSize;
        List<TUser> list = tUserDaoImpl.queryByPage(hql, offset, pageSize);

        /*打印输出看一波  非常正确 所有的数据都存进了pageBean*/
        Iterator<TUser> iterator = list.iterator();
        while(iterator.hasNext()){
            System.out.println("查询当前分页显示的数据是："+iterator.next().toString());
        }
        System.out.println("总记录数："+allRows);
        System.out.println("当前页面是："+currentPage);
        System.out.println("总页数是："+totalPage);

        pageBean.setList(list);
        pageBean.setAllRows(allRows);
        pageBean.setCurrentPage(currentPage);
        pageBean.setTotalPage(totalPage);

        return pageBean;
    }
}

4.TUserAction--action的定义
package com.pers.hoobey;

import com.opensymphony.xwork2.ActionSupport;
import org.apache.struts2.ServletActionContext;
import org.hibernate.Criteria;
import org.hibernate.Session;

import javax.servlet.http.HttpServletRequest;
import java.util.List;

public class TUserAction extends ActionSupport {
    private static final long serialVersionUID = 1L;
    private TUser user;
    private List<TUser> dataobject;//保存所有TUser数据集合

    TUserDaoImpl tUserDaoImpl = new TUserDaoImpl();

    TUserServiceImpl tUserServiceImpl = new TUserServiceImpl();
    private int page;
    //查询所有
    public String execute() throws Exception {
        Session session = HibernateSessionFactory.getSession();
        Criteria query = session.createCriteria(TUser.class);
        this.dataobject = (List<TUser>)query.list();
        for(TUser user : dataobject){
            System.out.println("id="+user.getId()+"name="+user.getName());
        }
        session.close();
        return SUCCESS;
    }
    // 增加数据
    public String addLine() throws Exception {
        System.out.print(user.getName());// user里面有内容
        user = tUserDaoImpl.busOper(user, 1);
        if (user == null)
            return ERROR;
        return SUCCESS;
    }
    //修改数据
    public String updLine() throws Exception{
        user= tUserDaoImpl.busOper(user, 0);
        if(user==null) return ERROR;
        return SUCCESS;
    }    
    //删除数据
    public String delLine() throws Exception{
        user= tUserDaoImpl.busOper(user, -1);//设计的很巧妙
        if(user==null) return ERROR;
        return SUCCESS;
    }
    //当前页数显示数据
    public String PageAll() throws Exception{
        //表示每页显示3条记录，page表示当前网页
        System.out.println("点击首页链接，进来了，返回出pageBean对象");
        PageBean pageBean = tUserServiceImpl.getPageBean(3, page);
        System.out.println(page);

        HttpServletRequest request = ServletActionContext.getRequest();

        request.setAttribute("pageBean", pageBean);//通过struts.xml的配置把pageBean值送到jsps/Alldata.jsp

        return SUCCESS;
    }

    public TUser getUser() {
        return user;
    }

    public void setUser(TUser user) {
        this.user = user;
    }
    public List<TUser> getDataobject() {
        return dataobject;
    }

    public void setDataobject(List<TUser> dataobject) {
        this.dataobject = dataobject;
    }

    public int getPage() {return page;}

    public void setPage(int page) {this.page = page;}
}

5.Alldata.jsp--页面信息显示
<%@ page language="java" import="java.util.*,com.pers.hoobey.*" pageEncoding="utf-8"%>
<%@ taglib uri="/struts-tags" prefix="s"%>
<%
    TUser user = new TUser(); 
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <script type="text/javascript">

        function validate() {
            var page = document.getElementsByName("page")[0].value;

            if (page > <s:property value="#request.pageBean.totalPage"/>) {
                alert("你输入的页数大于最大页数，页面将跳转到首页！");

                window.document.location.href = "TUserAction";

                return false;
            }

            return true;
        }

    </script>
</head>
<body>
    HQL 查询结果显示如下：
    <h1><font color="blue">分页查询</font></h1>
    <hr>
    <br>
    <table align="center">
        <tr>
            <td>序号</td>
            <td>姓名</td>
            <td>操作1</td>
            <td>操作2</td>
        </tr>
        <%--#request.pageBean.list  数据从TUserServiceImpl获取存入到PageBean--%>
        <s:iterator value="#request.pageBean.list" id="tUser">
            <tr>
                <td><s:property value="#tUser.id" /></td>
                <td><s:property value="#tUser.name" /></td>
                <!-- 修改不同id对应的数据 -->
                <td><a href="<%=request.getContextPath() %>/edit.jsp?user.id=<s:property value="#tUser.id" />">修改</a></td>
                <td><a href="delline.action?user.id=<s:property value="#tUser.id" />">删除</a></td>
            </tr>
        </s:iterator>
    </table>
<%--进行分页的页面布局--%>

    <center>

        <font size="5">共<font color="red"><s:property value="#request.pageBean.totalPage" /></font>页 </font>&nbsp;&nbsp;
        <font size="5">共<font color="red"><s:property value="#request.pageBean.allRows" /></font>条记录</font><br><br>

        <s:if test="#request.pageBean.currentPage == 1">
            首页&nbsp;&nbsp;&nbsp;上一页
        </s:if>

        <s:else>
            <%--进入此展示页面 必须点击首页链接  才会触动action去执行逻辑函数--%>
            <a href="TUserAction.action">首页</a>
            &nbsp;&nbsp;&nbsp;
            <a href="TUserAction.action?page=<s:property value="#request.pageBean.currentPage - 1"/>">上一页</a>
        </s:else>

        <s:if test="#request.pageBean.currentPage != #request.pageBean.totalPage">
            <a href="TUserAction.action?page=<s:property value="#request.pageBean.currentPage + 1"/>">下一页</a>
            &nbsp;&nbsp;&nbsp;
            <a href="TUserAction.action?page=<s:property value="#request.pageBean.totalPage"/>">尾页</a>
        </s:if>

        <s:else>
            下一页&nbsp;&nbsp;&nbsp;尾页
        </s:else>

    </center>
    <br>

    <center>

        <form action="TUserAction" onsubmit="return validate();">
            <font size="4">跳转至</font>
            <input type="text" size="2" name="page">页
            <input type="submit" value="跳转">
        </form>

    </center>
</body>
</html>