一、概述
今天自己做了个项目练练，然后有一些分页的功能，自己把分页的功能做了一个简单的总结，然后，为了以后能够方便自己的开发，做了一个baseDao的实现。
二、代码实现
2.1、分页的实体类pageBean
package org.sihai.utils;
import java.util.List;
public class PageBean {
//当前页数
private Integer currentPage;
//总记录数
private Integer totalCount;
//每页显示条数
private Integer pageSize;
//总页数
private Integer totalPage;
//分页列表数据
private List list;
public PageBean(Integer currentPage, Integer totalCount, Integer pageSize) {
this.totalCount = totalCount;
this.pageSize = pageSize;
this.currentPage = currentPage;
if(this.currentPage == null){
//如页面没有指定显示那一页.显示第一页.
this.currentPage = 1;
}
if(this.pageSize == null){
//如果每页显示条数没有指定,默认每页显示3条
this.pageSize = 3;
}
//计算总页数
this.totalPage = (this.totalCount+this.pageSize-1)/this.pageSize;
//判断当前页数是否超出范围
//不能小于1
if(this.currentPage < 1){
this.currentPage = 1;
}
//不能大于总页数
if(this.currentPage > this.totalPage){
this.currentPage = this.totalPage;
}
}
//计算起始索引
public int getStart(){
return (this.currentPage-1)*this.pageSize;
}
public Integer getCurrentPage() {
return currentPage;
}
public void setCurrentPage(Integer currentPage) {
this.currentPage = currentPage;
}
public Integer getTotalCount() {
return totalCount;
}
public void setTotalCount(Integer totalCount) {
this.totalCount = totalCount;
}
public Integer getPageSize() {
return pageSize;
}
public void setPageSize(Integer pageSize) {
this.pageSize = pageSize;
}
public Integer getTotalPage() {
return totalPage;
}
public void setTotalPage(Integer totalPage) {
this.totalPage = totalPage;
}
public List getList() {
return list;
}
public void setList(List list) {
this.list = list;
}
}
2.2、Action的实现
package org.sihai.web.action;
import org.apache.commons.lang3.StringUtils;
import org.hibernate.criterion.DetachedCriteria;
import org.hibernate.criterion.Restrictions;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.ModelDriven;
import org.sihai.domain.user;
import org.sihai.domain.User;
import org.sihai.service.userService;
import org.sihai.service.UserService;
import org.sihai.utils.PageBean;
public class userAction extends ActionSupport implements ModelDriven {
private user user = new user();
private userService cs;
private Integer currentPage;
private Integer pageSize;
public String list() throws Exception {
//封装离线查询对象
DetachedCriteria dc = DetachedCriteria.forClass(user.class);
//判断并封装参数
if(StringUtils.isNotBlank(user.getuser_name())){
dc.add(Restrictions.like("user_name", "%"+user.getuser_name()+"%"));
}
//1 调用Service查询分页数据(PageBean)
PageBean pb = cs.getPageBean(dc,currentPage,pageSize);
//2 将PageBean放入request域,转发到列表页面显示
ActionContext.getContext().put("pageBean", pb);
return "list";
}
@Override
public user getModel() {
return user;
}
public void setCs(userService cs) {
this.cs = cs;
}
public Integer getCurrentPage() {
return currentPage;
}
public void setCurrentPage(Integer currentPage) {
this.currentPage = currentPage;
}
public Integer getPageSize() {
return pageSize;
}
public void setPageSize(Integer pageSize) {
this.pageSize = pageSize;
}
}
2.3、service的实现
package org.sihai.service.impl;
import java.util.List;
import org.hibernate.criterion.DetachedCriteria;
import org.sihai.dao.userDao;
import org.sihai.domain.user;
import org.sihai.service.userService;
import org.sihai.utils.PageBean;
public class userServiceImpl implements userService {
private userDao cd;
@Override
public PageBean getPageBean(DetachedCriteria dc, Integer currentPage, Integer pageSize) {
//1 调用Dao查询总记录数
Integer totalCount = cd.getTotalCount(dc);
//2 创建PageBean对象
PageBean pb = new PageBean(currentPage, totalCount, pageSize);
//3 调用Dao查询分页列表数据
List list = cd.getPageList(dc,pb.getStart(),pb.getPageSize());
//4 列表数据放入pageBean中.并返回
pb.setList(list);
return pb;
}
public void setCd(userDao cd) {
this.cd = cd;
}
}
2.4、baseDao的具体实现（通用基类）
package org.sihai.dao.impl;
import java.io.Serializable;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.List;
import org.hibernate.criterion.DetachedCriteria;
import org.hibernate.criterion.Projections;
import org.springframework.orm.hibernate5.support.HibernateDaoSupport;
import org.sihai.dao.BaseDao;
import org.sihai.domain.user;
public class BaseDaoImpl extends HibernateDaoSupport implements BaseDao {
private Class clazz;//用于接收运行期泛型类型
public BaseDaoImpl() {
//获得当前类型的带有泛型类型的父类
ParameterizedType ptClass = (ParameterizedType) this.getClass().getGenericSuperclass();
//获得运行期的泛型类型
clazz = (Class) ptClass.getActualTypeArguments()[0];
}
@Override
public void save(T t) {
getHibernateTemplate().save(t);
}
@Override
public void delete(T t) {
getHibernateTemplate().delete(t);
}
@Override
public void delete(Serializable id) {
T t = this.getById(id);//先取,再删
getHibernateTemplate().delete(t);
}
@Override
public void update(T t) {
getHibernateTemplate().update(t);
}
@Override
public T getById(Serializable id) {
return (T) getHibernateTemplate().get(clazz, id);
}
@Override
public Integer getTotalCount(DetachedCriteria dc) {
//设置查询的聚合函数,总记录数
dc.setProjection(Projections.rowCount());
List list = (List) getHibernateTemplate().findByCriteria(dc);
//清空之前设置的聚合函数
dc.setProjection(null);
if(list!=null && list.size()>0){
Long count = list.get(0);
return count.intValue();
}else{
return null;
}
}
@Override
public List getPageList(DetachedCriteria dc, Integer start, Integer pageSize) {
List list = (List) getHibernateTemplate().findByCriteria(dc, start, pageSize);
return list;
}
}
2.5、baseService的具体实现
package org.sihai.qualitycontrol.util.base;
import java.io.Serializable;
import java.util.List;
import org.springframework.transaction.annotation.Transactional;
@Transactional
public interface BaseEbi {
public void save(T t);
public void update(T t);
public void delete(T t);
public List getAll();
public T get(Serializable uuid);
public List getAll(BaseQueryModel qm, Integer pageNum,Integer pageCount);
public Integer getCount(BaseQueryModel qm);
}
2.6、baseAction的具体实现
package org.sihai.qualitycontrol.util.base;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts2.ServletActionContext;
import org.sihai.qualitycontrol.auth.emp.vo.EmpModel;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;
public class BaseAction extends ActionSupport{
public static final String LIST = "list";
public static final String TO_LIST = "toList";
public static final String INPUT = "input";
public Integer pageNum = 1;
public Integer pageCount = 10;
public Integer maxPageNum;
public Integer dataTotal;
public String getActionName(){
//动态
//DepAction ->dep
//EmpAction ->emp
String actionName = this.getClass().getSimpleName();
//DepAction ->Dep
String temp = actionName.substring(0, actionName.length()-6);
//Dep ->dep OrderDetailAction ->orderDetail orderdetail
return temp.substring(0,1).toLowerCase()+temp.substring(1);
}
protected void setDataTotal(int dataTotal){
this.dataTotal = dataTotal ;
maxPageNum = (dataTotal + pageCount -1) / pageCount;
}
protected void put(String name,Object obj){
ActionContext.getContext().put(name,obj);
}
protected Object get(String name){
return ActionContext.getContext().get(name);
}
protected void putSession(String name,Object obj){
ActionContext.getContext().getSession().put(name,obj);
}
protected Object getSession(String name){
return ActionContext.getContext().getSession().get(name);
}
protected EmpModel getLogin(){
return (EmpModel) getSession(EmpModel.EMP_LOGIN_USER_OBJECT_NAME);
}
protected HttpServletRequest getRequest(){
return ServletActionContext.getRequest();
}
protected HttpServletResponse getResponse(){
return ServletActionContext.getResponse();
}
}
2.7、页面的实现
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ taglib prefix="s" uri="/struts-tags" %>
客户列表
当前位置：客户管理 > 客户列表
客户名称
客户级别
客户来源
联系人
电话
手机
操作
修改
删除
三、通用分页实现
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@taglib prefix="s" uri="/struts-tags"%>
共${dataTotal}条记录
首 页
上一页
下一页
末 页
当前第${pageNum}/${maxPageNum }页
四、总结
以前这样的总结还是比较少的，以至于在以后的开发，很多的模块的小的东西还需要重新的来思考，很是浪费时间，希望以后能够坚持。。。
欢迎关注我的微信公众号
好好学java，在公众号里，回复：java基础、html5、javaEE基础、struts2、spring、redis、luncene、oracle等，将可获得以上的优质视频教程及源码。