package com.how2java.tmall.util;
 
import java.util.List;

import org.springframework.data.domain.Page;
 
public class Page4Navigator<T> {
    Page<T> pageFromJPA;
    int navigatePages;
     
    int totalPages;
 
    int number;
     
    long totalElements;
     
    int size;
 
    int numberOfElements;
 
    List<T> content;
 
    boolean isHasContent;
 
    boolean first;
 
    boolean last;
     
    boolean isHasNext;
 
    boolean isHasPrevious;
     
    int[] navigatepageNums;
     
    public Page4Navigator() {
        //这个空的分页是为了 Redis 从 json格式转换为 Page4Navigator 对象而专门提供的
    }
     
    public Page4Navigator(Page<T> pageFromJPA,int navigatePages) {
        this.pageFromJPA = pageFromJPA;
        this.navigatePages = navigatePages;
         
        totalPages = pageFromJPA.getTotalPages();
         
        number  = pageFromJPA.getNumber() ;
         
        totalElements = pageFromJPA.getTotalElements();
         
        size = pageFromJPA.getSize();
         
        numberOfElements = pageFromJPA.getNumberOfElements();
         
        content = pageFromJPA.getContent();
         
        isHasContent = pageFromJPA.hasContent();
                 
        first = pageFromJPA.isFirst();
         
        last = pageFromJPA.isLast();
         
        isHasNext = pageFromJPA.hasNext();
         
        isHasPrevious  = pageFromJPA.hasPrevious();       
         
        calcNavigatepageNums();
         
    }
 
    private void calcNavigatepageNums() {
        int navigatepageNums[];
        int totalPages = getTotalPages();
        int num = getNumber();
        //当总页数小于或等于导航页码数时
        if (totalPages <= navigatePages) {
            navigatepageNums = new int[totalPages];
            for (int i = 0; i < totalPages; i++) {
                navigatepageNums[i] = i + 1;
            }
        } else { //当总页数大于导航页码数时
            navigatepageNums = new int[navigatePages];
            int startNum = num - navigatePages / 2;
            int endNum = num + navigatePages / 2;
 
            if (startNum < 1) {
                startNum = 1;
                //(最前navigatePages页
                for (int i = 0; i < navigatePages; i++) {
                    navigatepageNums[i] = startNum++;
                }
            } else if (endNum > totalPages) {
                endNum = totalPages;
                //最后navigatePages页
                for (int i = navigatePages - 1; i >= 0; i--) {
                    navigatepageNums[i] = endNum--;
                }
            } else {
                //所有中间页
                for (int i = 0; i < navigatePages; i++) {
                    navigatepageNums[i] = startNum++;
                }
            }
        }  
        this.navigatepageNums = navigatepageNums;
    }
 
    public int getNavigatePages() {
        return navigatePages;
    }
 
    public void setNavigatePages(int navigatePages) {
        this.navigatePages = navigatePages;
    }
 
    public int getTotalPages() {
        return totalPages;
    }
 
    public void setTotalPages(int totalPages) {
        this.totalPages = totalPages;
    }
 
    public int getNumber() {
        return number;
    }
 
    public void setNumber(int number) {
        this.number = number;
    }
 
    public long getTotalElements() {
        return totalElements;
    }
 
    public void setTotalElements(long totalElements) {
        this.totalElements = totalElements;
    }
 
    public int getSize() {
        return size;
    }
 
    public void setSize(int size) {
        this.size = size;
    }
 
    public int getNumberOfElements() {
        return numberOfElements;
    }
 
    public void setNumberOfElements(int numberOfElements) {
        this.numberOfElements = numberOfElements;
    }
 
    public List<T> getContent() {
        return content;
    }
 
    public void setContent(List<T> content) {
        this.content = content;
    }
 
    public boolean isHasContent() {
        return isHasContent;
    }
 
    public void setHasContent(boolean isHasContent) {
        this.isHasContent = isHasContent;
    }
 
    public boolean isFirst() {
        return first;
    }
 
    public void setFirst(boolean first) {
        this.first = first;
    }
 
    public boolean isLast() {
        return last;
    }
 
    public void setLast(boolean last) {
        this.last = last;
    }
 
    public boolean isHasNext() {
        return isHasNext;
    }
 
    public void setHasNext(boolean isHasNext) {
        this.isHasNext = isHasNext;
    }
 
    public boolean isHasPrevious() {
        return isHasPrevious;
    }
 
    public void setHasPrevious(boolean isHasPrevious) {
        this.isHasPrevious = isHasPrevious;
    }
 
    public int[] getNavigatepageNums() {
        return navigatepageNums;
    }
 
    public void setNavigatepageNums(int[] navigatepageNums) {
        this.navigatepageNums = navigatepageNums;
    }
 
}

package com.how2java.tmall.service;

import java.util.List;

import com.how2java.tmall.util.Page4Navigator;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.stereotype.Service;

import com.how2java.tmall.dao.CategoryDAO;
import com.how2java.tmall.pojo.Category;

@Service
public class CategoryService {
	@Autowired CategoryDAO categoryDAO;

	public Page4Navigator<Category> list(int start, int size, int navigatePages) {
		Sort sort = new Sort(Sort.Direction.DESC, "id");
		Pageable pageable = new PageRequest(start, size,sort);
		Page pageFromJPA =categoryDAO.findAll(pageable);

		return new Page4Navigator<>(pageFromJPA,navigatePages);
	}
	public List<Category> list() {
    	Sort sort = new Sort(Sort.Direction.DESC, "id");
		return categoryDAO.findAll(sort);
	}
}

package com.how2java.tmall.web;

import com.how2java.tmall.pojo.Category;
import com.how2java.tmall.service.CategoryService;
import com.how2java.tmall.util.Page4Navigator;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;
 
@RestController
public class CategoryController {
	@Autowired CategoryService categoryService;

	@GetMapping("/categories")
	public Page4Navigator<Category> list(@RequestParam(value = "start", defaultValue = "0") int start, @RequestParam(value = "size", defaultValue = "5") int size) throws Exception {
		start = start<0?0:start;
		Page4Navigator<Category> page =categoryService.list(start, size, 5);  //5表示导航分页最多有5个，像 [1,2,3,4,5] 这样
		return page;
	}

}

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">

<head th:include="include/admin/adminHeader::html('分类管理')" ></head>
<body>
<div th:replace="include/admin/adminNavigator::html" ></div>
<script>
    $(function(){
        var data4Vue = {
            uri:'categories',
            pagination:{},
            beans: []
        };

        //ViewModel
        var vue = new Vue({
            el: '#workingArea',
            data: data4Vue,
            mounted:function(){ //mounted　表示这个 Vue 对象加载成功了
                this.list(0);
            },
            methods: {
                list:function(start){
                    var url =  this.uri+ "?start="+start;
                    axios.get(url).then(function(response) {
                        vue.pagination = response.data;
                        vue.beans = response.data.content	;
                    });
                },
                jump: function(page){
                    jump(page,vue); //定义在adminHeader.html 中
                },
                jumpByNumber: function(start){
                    jumpByNumber(start,vue);
                }
            }
        });
    });

</script>
<div id="workingArea" >
    <h1 class="label label-info" >分类管理</h1>
    <br>
    <br>
    <div class="listDataTableDiv">
        <table class="table table-striped table-bordered table-hover  table-condensed">
            <thead>
            <tr class="success">
                <th>ID</th>
                <th>图片</th>
                <th>分类名称</th>
                <th>属性管理</th>
                <th>产品管理</th>
                <th>编辑</th>
                <th>删除</th>
            </tr>
            </thead>
            <tbody>
            <tr v-for="bean in beans ">
                <td>{{bean.id}}</td>
                <td>
                    <img height="40px"  :src="'img/category/'+bean.id+'.jpg'">
                </td>
                <td>
                    {{bean.name}}
                </td>
                <td>
                    <a :href="'admin_property_list?cid=' + bean.id "><span class="glyphicon glyphicon-th-list"></span></a>
                </td>
                <td>
                    <a :href="'admin_product_list?cid=' + bean.id "><span class="glyphicon glyphicon-shopping-cart"></span></a>
                </td>
                <td>
                    <a :href="'admin_category_edit?id=' + bean.id "><span class="glyphicon glyphicon-edit"></span></a>
                </td>
                <td>
                    <a href="#nowhere"  @click="deleteBean(bean.id)"><span class="   glyphicon glyphicon-trash"></span></a>
                </td>
            </tr>
            </tbody>
        </table>
    </div>
    <div th:replace="include/admin/adminPage::html" ></div>
</div>
<div th:replace="include/admin/adminFooter::html" ></div>
</body>
</html>

<div class="pageDiv" th:fragment="html">
	<nav>
	  <ul class="pagination">
	    <li :class="{ disabled: pagination.first }">
	      <a  href="#nowhere" @click="jump('first')">«</a>
	    </li>
	    <li :class="{ disabled: !pagination.hasPrevious }">
	      <a  href="#nowhere" @click="jump('pre')">‹</a>
	    </li>		    

		<li  v-for="i in pagination.navigatepageNums">
			<a href="#nowhere" @click="jumpByNumber(i-1)" >
				{{i}}
			</a>
		</li>

	    <li :class="{ disabled: !pagination.hasNext }">
	      <a  href="#nowhere" @click="jump('next')">›</a>
	    </li>
	    <li :class="{ disabled: pagination.last }">
	      <a  href="#nowhere" @click="jump('last')"> »</a>
	    </li>		    
	  </ul>
	</nav>    
</div>

	//jpa 传递出来的分页对象， Page4Navigator 类就是对它进行封装以达到扩展的效果
    Page<T> pageFromJPA;
    
    //分页的时候 ,如果总页数比较多，那么显示出来的分页超链一个有几个。 比如如果分页出来的超链是这样的： [8,9,10,11,12], 那么 navigatePages 就是5
    int navigatePages;
     
    //总页面数
    int totalPages;
 
    //第几页（基0）
    int number;
     
    //总共有多少条数据
    long totalElements;
     
    //一页最多有多少条数据
    int size;
 
    //当前页有多少条数据 (与 size，不同的是，最后一页可能不满 size 个)
    int numberOfElements;
 
    //数据集合
    List<T> content;
 
    //是否有数据
    boolean isHasContent;
 
    //是否是首页
    boolean first;
 
    //是否是末页
    boolean last;
     
    //是否有下一页
    boolean isHasNext;
 
    //是否有上一页
    boolean isHasPrevious;
     
    //分页的时候 ,如果总页数比较多，那么显示出来的分页超链一个有几个。 比如如果分页出来的超链是这样的： [8,9,10,11,12]，那么 navigatepageNums 就是这个数组：[8,9,10,11,12]，这样便于前端展示
    int[] navigatepageNums;