JavaWeb--简单分页技术

分页需要的技术点：1.前台分页标签的使用

　　　　　　　　　2.前台上一页，下一页显示的业务逻辑

　　　　　　　　　3.MSQL用到的语句  limit

　　　　　　　　　4.封装pageBean对象

这个是PageBean用到的

分页公式：

1. int totalPageNum = (totalRecord  +  pageSize  - 1) / pageSize;

package com.itheima.vo;

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

import com.itheima.domain.Product;

public class PageBean<T> {

    //当前页
    private int currentPage;
    //当前页显示的条数
    private int currentCount;
    //总条数
    private int totalCount;
    //总页数
    private int totalPage;
    //每页显示的数据
    private List<T> productList = new ArrayList<T>();

    public int getCurrentPage() {
        return currentPage;
    }
    public void setCurrentPage(int currentPage) {
        this.currentPage = currentPage;
    }
    public int getCurrentCount() {
        return currentCount;
    }
    public void setCurrentCount(int currentCount) {
        this.currentCount = currentCount;
    }
    public int getTotalCount() {
        return totalCount;
    }
    public void setTotalCount(int totalCount) {
        this.totalCount = totalCount;
    }
    public int getTotalPage() {
        return totalPage;
    }
    public void setTotalPage(int totalPage) {
        this.totalPage = totalPage;
    }
    public List<T> getProductList() {
        return productList;
    }
    public void setProductList(List<T> productList) {
        this.productList = productList;
    }

}

前台页面上的分页标签显示逻辑

    <!--分页 -->
    <div style="width: 380px; margin: 0 auto; margin-top: 50px;">
        <ul class="pagination" style="text-align: center; margin-top: 10px;">
            <!-- 上一页 -->
            <!-- 判断当前页是否是第一页 -->
            <c:if test="${pageBean.currentPage==1 }">
                <li class="disabled">
                    <a href="javascript:void(0);" aria-label="Previous">
                        <span aria-hidden="true">&laquo;</span>
                    </a>
                </li>
            </c:if>
            <c:if test="${pageBean.currentPage!=1 }">
                <li>
                    <a href="${pageContext.request.contextPath }/productList?currentPage=${pageBean.currentPage-1}" aria-label="Previous">
                        <span aria-hidden="true">&laquo;</span>
                    </a>
                </li>
            </c:if>    

            <c:forEach begin="1" end="${pageBean.totalPage }" var="page">
                <!-- 判断当前页 -->
                <c:if test="${pageBean.currentPage==page }">
                    <li class="active"><a href="javascript:void(0);">${page}</a></li>
                </c:if>
                <c:if test="${pageBean.currentPage!=page }">
                    <li><a href="${pageContext.request.contextPath }/productList?currentPage=${page}">${page}</a></li>
                </c:if>

            </c:forEach>

            <!-- 判断当前页是否是最后一页 -->
            <c:if test="${pageBean.currentPage==pageBean.totalPage }">
                <li class="disabled">
                    <a href="javascript:void(0);" aria-label="Next">
                        <span aria-hidden="true">&raquo;</span>
                    </a>
                </li>
            </c:if>
            <c:if test="${pageBean.currentPage!=pageBean.totalPage }">
                <li>
                    <a href="${pageContext.request.contextPath }/productList?currentPage=${pageBean.currentPage+1}" aria-label="Next">
                        <span aria-hidden="true">&raquo;</span>
                    </a>
                </li>
            </c:if>

        </ul>
    </div>
    <!-- 分页结束 -->