Page.java

/**
 * Copyright © 2012-2013 <a href="https://github.com/thinkgem/jeesite">JeeSite</a> All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 */
package com.fang.bbks.common.persistence;

import java.util.ArrayList;
import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.lang3.StringUtils;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.data.domain.Sort.Direction;
import org.springframework.data.domain.Sort.Order;

import com.fang.bbks.common.utils.CookieUtils;

/**
 * 分页类
 * @author ThinkGem
 * @version 2013-01-15
 * @param <T>
 */
public class Page<T> {
	
	private int pageNo = 1; // 当前页码
	private int pageSize = 20; // 页面大小，设置为“-1”表示不进行分页（分页无效）
	
	private long count;// 总记录数，设置为“-1”表示不查询总数
	
	private int first;// 首页索引
	private int last;// 尾页索引
	private int prev;// 上一页索引
	private int next;// 下一页索引
	
	private boolean firstPage;//是否是第一页
	private boolean lastPage;//是否是最后一页

	private int length = 8;// 显示页面长度
	private int slider = 1;// 前后显示页面长度
		
	private List<T> list = new ArrayList<T>();
	
	private String orderBy = ""; // 标准查询有效， 实例： updatedate desc, name asc
	
	private String funcName = "page"; // 设置点击页码调用的js函数名称，默认为page，在一页有多个分页对象时使用。

	/**
	 * 构造方法
	 * @param request 传递 repage 参数，来记住页码
	 * @param response 用于设置 Cookie，记住页码
	 */
	public Page(HttpServletRequest request, HttpServletResponse response){
		this(request, response, -1);
	}
	
	/**
	 * 构造方法
	 * @param request 传递 repage 参数，来记住页码
	 * @param response 用于设置 Cookie，记住页码
	 * @param pageSize 分页大小，如果传递 -1 则为不分页，返回所有数据
	 */
	public Page(HttpServletRequest request, HttpServletResponse response, int pageSize){
		// 设置页码参数（传递repage参数，来记住页码）
		String no = request.getParameter("pageNo");
		if (StringUtils.isNumeric(no)){
			CookieUtils.setCookie(response, "pageNo", no);
			this.setPageNo(Integer.parseInt(no));
		}else if (request.getParameter("repage")!=null){
			no = CookieUtils.getCookie(request, "pageNo");
			if (StringUtils.isNumeric(no)){
				this.setPageNo(Integer.parseInt(no));
			}
		}
		// 设置页面大小参数（传递repage参数，来记住页码大小）
		if (pageSize==-1){
			String size = request.getParameter("pageSize");
			if (StringUtils.isNumeric(size)){
				CookieUtils.setCookie(response, "pageSize", size);
				this.setPageSize(Integer.parseInt(size));
			}else if (request.getParameter("repage")!=null){
				no = CookieUtils.getCookie(request, "pageSize");
				if (StringUtils.isNumeric(size)){
					this.setPageSize(Integer.parseInt(size));
				}
			}
		}else{
			this.setPageSize(pageSize);
		}
		// 设置排序参数
		String orderBy = request.getParameter("orderBy");
		if (StringUtils.isNotBlank(orderBy)){
			this.setOrderBy(orderBy);
		}
	}
	
	/**
	 * 构造方法
	 * @param pageNo 当前页码
	 * @param pageSize 分页大小
	 */
	public Page(int pageNo, int pageSize) {
		this(pageNo, pageSize, 0);
	}
	
	/**
	 * 构造方法
	 * @param pageNo 当前页码
	 * @param pageSize 分页大小
	 * @param count 数据条数
	 */
	public Page(int pageNo, int pageSize, long count) {
		this(pageNo, pageSize, count, new ArrayList<T>());
	}
	
	/**
	 * 构造方法
	 * @param pageNo 当前页码
	 * @param pageSize 分页大小
	 * @param count 数据条数
	 * @param list 本页数据对象列表
	 */
	public Page(int pageNo, int pageSize, long count, List<T> list) {
		this.setCount(count);
		this.setPageNo(pageNo);
		this.setPageSize(pageSize);
		this.setList(list);
	}
	
	/**
	 * 初始化参数
	 */
	public void initialize(){
				
		//1
		this.first = 1;
		
		this.last = (int)(count / (this.pageSize < 1 ? 20 : this.pageSize) + first - 1);
		
		if (this.count % this.pageSize != 0 || this.last == 0) {
			this.last++;
		}

		if (this.last < this.first) {
			this.last = this.first;
		}
		
		if (this.pageNo <= 1) {
			this.pageNo = this.first;
			this.firstPage=true;
		}

		if (this.pageNo >= this.last) {
			this.pageNo = this.last;
			this.lastPage=true;
		}

		if (this.pageNo < this.last - 1) {
			this.next = this.pageNo + 1;
		} else {
			this.next = this.last;
		}

		if (this.pageNo > 1) {
			this.prev = this.pageNo - 1;
		} else {
			this.prev = this.first;
		}
		
		//2
		if (this.pageNo < this.first) {// 如果当前页小于首页
			this.pageNo = this.first;
		}

		if (this.pageNo > this.last) {// 如果当前页大于尾页
			this.pageNo = this.last;
		}
		
	}
	
	/**
	 * 默认输出当前分页标签 
	 * <div class="page">${page}</div>
	 */
	@Override
	public String toString() {

		initialize();
		
		StringBuilder sb = new StringBuilder();
		
		if (pageNo == first) {// 如果是首页
			sb.append("<li class=\"disabled\"><a href=\"javascript:\">« 上一页</a></li>\n");
		} else {
			sb.append("<li><a href=\"javascript:"+funcName+"("+prev+","+pageSize+");\">« 上一页</a></li>\n");
		}

		int begin = pageNo - (length / 2);

		if (begin < first) {
			begin = first;
		}

		int end = begin + length - 1;

		if (end >= last) {
			end = last;
			begin = end - length + 1;
			if (begin < first) {
				begin = first;
			}
		}

		if (begin > first) {
			int i = 0;
			for (i = first; i < first + slider && i < begin; i++) {
				sb.append("<li><a href=\"javascript:"+funcName+"("+i+","+pageSize+");\">"
						+ (i + 1 - first) + "</a></li>\n");
			}
			if (i < begin) {
				sb.append("<li class=\"disabled\"><a href=\"javascript:\">...</a></li>\n");
			}
		}

		for (int i = begin; i <= end; i++) {
			if (i == pageNo) {
				sb.append("<li class=\"active\"><a href=\"javascript:\">" + (i + 1 - first)
						+ "</a></li>\n");
			} else {
				sb.append("<li><a href=\"javascript:"+funcName+"("+i+","+pageSize+");\">"
						+ (i + 1 - first) + "</a></li>\n");
			}
		}

		if (last - end > slider) {
			sb.append("<li class=\"disabled\"><a href=\"javascript:\">...</a></li>\n");
			end = last - slider;
		}

		for (int i = end + 1; i <= last; i++) {
			sb.append("<li><a href=\"javascript:"+funcName+"("+i+","+pageSize+");\">"
					+ (i + 1 - first) + "</a></li>\n");
		}

		if (pageNo == last) {
			sb.append("<li class=\"disabled\"><a href=\"javascript:\">下一页 »</a></li>\n");
		} else {
			sb.append("<li><a href=\"javascript:"+funcName+"("+next+","+pageSize+");\">"
					+ "下一页 »</a></li>\n");
		}

		sb.append("<li class=\"disabled\"><a href=\"javascript:\" style=\"border:0;padding-top:1px;_padding-top:7px;\">当前 ");
		sb.append("<input type=\"text\" value=\""+pageNo+"\" style=\"width:30px;padding:0;margin:0 2px 3px 2px;text-align:center;\" ");
		sb.append("onkeypress=\"if(window.event.keyCode==13) "+funcName+"(this.value,"+pageSize+");\" onclick=\"this.select();\"/> / ");
		sb.append("<input type=\"text\" value=\""+pageSize+"\" style=\"width:30px;padding:0;margin:0 2px 3px 2px;text-align:center;\" ");
		sb.append("onkeypress=\"if(window.event.keyCode==13) "+funcName+"("+pageNo+",this.value);\" onclick=\"this.select();\"/> 条，");
		sb.append("共 " + count + " 条</a><li>\n");

		sb.insert(0,"<ul>\n").append("</ul>\n");
		
		sb.append("<div style=\"clear:both;\"></div>");

//		sb.insert(0,"<div class=\"page\">\n").append("</div>\n");
		
		return sb.toString();
	}
	
	public static void main(String[] args) {
		Page<String> p = new Page<String>(3, 3);
		System.out.println(p);
		System.out.println("首页："+p.getFirst());
		System.out.println("尾页："+p.getLast());
		System.out.println("上页："+p.getPrev());
		System.out.println("下页："+p.getNext());
	}

	/**
	 * 获取设置总数
	 * @return
	 */
	public long getCount() {
		return count;
	}

	/**
	 * 设置数据总数
	 * @param count
	 */
	public void setCount(long count) {
		this.count = count;
		if (pageSize >= count){
			pageNo = 1;
		}
	}
	
	/**
	 * 获取当前页码
	 * @return
	 */
	public int getPageNo() {
		return pageNo;
	}
	
	/**
	 * 设置当前页码
	 * @param pageNo
	 */
	public void setPageNo(int pageNo) {
		this.pageNo = pageNo;
	}
	
	/**
	 * 获取页面大小
	 * @return
	 */
	public int getPageSize() {
		return pageSize;
	}

	/**
	 * 设置页面大小（最大500）
	 * @param pageSize
	 */
	public void setPageSize(int pageSize) {
		this.pageSize = pageSize > 500 ? 500 : pageSize;
	}

	/**
	 * 首页索引
	 * @return
	 */
	public int getFirst() {
		return first;
	}

	/**
	 * 尾页索引
	 * @return
	 */
	public int getLast() {
		return last;
	}
	
	/**
	 * 获取页面总数
	 * @return getLast();
	 */
	public int getTotalPage() {
		return getLast();
	}

	/**
	 * 是否为第一页
	 * @return
	 */
	public boolean isFirstPage() {
		return firstPage;
	}

	/**
	 * 是否为最后一页
	 * @return
	 */
	public boolean isLastPage() {
		return lastPage;
	}
	
	/**
	 * 上一页索引值
	 * @return
	 */
	public int getPrev() {
		if (isFirstPage()) {
			return pageNo;
		} else {
			return pageNo - 1;
		}
	}

	/**
	 * 下一页索引值
	 * @return
	 */
	public int getNext() {
		if (isLastPage()) {
			return pageNo;
		} else {
			return pageNo + 1;
		}
	}
	
	/**
	 * 获取本页数据对象列表
	 * @return List<T>
	 */
	public List<T> getList() {
		return list;
	}

	/**
	 * 设置本页数据对象列表
	 * @param list
	 */
	public void setList(List<T> list) {
		this.list = list;
	}

	/**
	 * 获取查询排序字符串
	 * @return
	 */
	public String getOrderBy() {
		return orderBy;
	}

	/**
	 * 设置查询排序，标准查询有效， 实例： updatedate desc, name asc
	 */
	public void setOrderBy(String orderBy) {
		this.orderBy = orderBy;
	}

	/**
	 * 获取点击页码调用的js函数名称
	 * function ${page.funcName}(pageNo){location="${ctx}/list-${category.id}${urlSuffix}?pageNo="+i;}
	 * @return
	 */
	public String getFuncName() {
		return funcName;
	}

	/**
	 * 设置点击页码调用的js函数名称，默认为page，在一页有多个分页对象时使用。
	 * @param funcName 默认为page
	 */
	public void setFuncName(String funcName) {
		this.funcName = funcName;
	}
	
	/**
	 * 分页是否有效
	 * @return this.pageSize==-1
	 */
	public boolean isDisabled() {
		return this.pageSize==-1;
	}
	
	/**
	 * 是否进行总数统计
	 * @return this.count==-1
	 */
	public boolean isNotCount() {
		return this.count==-1;
	}
	
	/**
	 * 获取 Hibernate FirstResult
	 */
	public int getFirstResult(){
		int firstResult = (getPageNo() - 1) * getPageSize();
		if (firstResult >= getCount()) {
			firstResult = 0;
		}
		return firstResult;
	}
	/**
	 * 获取 Hibernate MaxResults
	 */
	public int getMaxResults(){
		return getPageSize();
	}
	
	public boolean isNormal(int queryPageNo){
		System.out.println("queryPageNo:"+queryPageNo);
		System.out.println("pageNo:"+getPageNo());
		System.out.println("pageSize:"+getPageSize());
		
		if(queryPageNo != getPageNo()){
			return false;
		}
		
		if(queryPageNo > 1){
			if(getFirstResult() == 0){
				return false;
			}
			return ((getPageNo() - 1) * getPageSize()) == getFirstResult() ;
		}else{
			if(getFirstResult() == 0){
				return true;
			}
			return false;
		}
	}   

	/**
	 * 获取 Spring data JPA 分页对象
	 */
	public Pageable getSpringPage(){
		List<Order> orders = new ArrayList<Order>();
		if (orderBy!=null){
			for (String order : StringUtils.split(orderBy, ",")){
				String[] o = StringUtils.split(order, " ");
				if (o.length>=1){
					orders.add(new Order(Direction.ASC, o[0]));
				}else if (o.length>=2){
					if ("DESC".equals(o[1].toUpperCase())){
						orders.add(new Order(Direction.DESC, o[0]));
					}else{
						orders.add(new Order(Direction.ASC, o[0]));
					}
				}
			}
		}
		return new PageRequest(this.pageNo - 1, this.pageSize, new Sort(orders));
	}
	
	/**
	 * 设置 Spring data JPA 分页对象，转换为本系统分页对象
	 */
	public void setSpringPage(org.springframework.data.domain.Page<T> page){
		this.pageNo = page.getNumber();
		this.pageSize = page.getSize();
		this.count = page.getTotalElements();
		this.list = page.getContent();
	}
}