商品增删改查之分页显示

首先需要创建一个javaBean

public class PageBean<T> {
    
    private Integer currentPage;//当前页数      
    
    private Integer pagesize;//每页显示的数目
    
    private Integer totalCount;//总条目数
    
    private Integer totalPage;//总页数
    
    private List<T> list;//用来封装商品集合
    
    public List<T> getList() {
        return list;
    }

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

    

    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;
    }

    public Integer getTotalCount() {
        return totalCount;
    }

    public void setTotalCount(Integer totalCount) {
        this.totalCount = totalCount;
    }

    public Integer getTotalPage() {
        return totalPage;
    }

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

}

然后需要请求servlet用来处理

public String findByCid(HttpServletRequest request,
            HttpServletResponse response) {
        try {
            // 接受参数
            String cid = request.getParameter("cid");
            Integer currentPage = Integer.parseInt(request
                    .getParameter("currentPage"));
            // 调用业务层
            ProductService productService = (ProductService) BeanFactory.getBean("productService");
            PageBean<Product> pageBean = productService.findByPageCid(cid,
                    currentPage);
            // 将数据放入域中
            request.setAttribute("pageBean", pageBean);
            return "/jsp/product_list.jsp";
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException();
        }

    }

然后调用service来处理封装数据

/*
     * 用于分页查询商品分类
     * 并且在业务层封装pageBean的信息
     */
    public PageBean<Product> findByPageCid(String cid, Integer currentPage) throws SQLException {
        PageBean<Product> pageBean = new PageBean<Product>();
        //设置当前页数
        pageBean.setCurrentPage(currentPage);
        //设置每页读取的商品数目
        Integer pagesize = 12;
        pageBean.setPagesize(pagesize);
        //设置总的记录数
        ProductDao productDao = (ProductDao) BeanFactory.getBean("productDao");
        Integer count = productDao.findCount(cid);
        pageBean.setTotalCount(count);
        //设置总页数
        double tc = count;
        Double totalPage = Math.ceil(tc/pagesize);
        pageBean.setTotalPage(totalPage.intValue());
        
        //设置每页显示数据的商品的集合        1 10   2 11-20 
        int begin = (currentPage-1)*pagesize;
        List<Product> list = productDao.findByCid(cid, begin, pagesize);
        pageBean.setList(list);
        
        return pageBean;
        
    }

调用DAO来查询数据库

    /*
     * 分页查询商品
     */
    public List<Product> findByCid(String cid, int begin, Integer pagesize) throws SQLException {
        QueryRunner queryRunner = new QueryRunner(JDBCUtils.getDataSource());
        String sql = "select * from product where pflag = ? and cid = ? order by pdate desc limit ?,?";
        List<Product> list = queryRunner.query(sql, new BeanListHandler<Product>(Product.class),0,cid,begin,pagesize);
        return list;
    }

将封装的数据返回并在jsp中获取

<div style="width: 380px; margin: 0 auto; margin-top: 50px;">

        <ul class="pagination" style="text-align: center; margin-top: 10px;">
            <c:if test="${pageBean.currentPage!=1 }">
                <li ><a
                    href="${pageContext.request.contextPath}/ProductServlet?cid=${param.cid }&method=findByCid&currentPage=${pageBean.currentPage-1 }"
                    aria-label="Previous"><span aria-hidden="true">&laquo;</span></a></li>
            </c:if>
            <c:forEach var="i" begin="1" end="${ pageBean.totalPage }">
                <c:if test="${pageBean.currentPage==i}">
                    <li class="active"><a href="#">${i }</a></li>
                </c:if>

                <c:if test="${pageBean.currentPage!=i}">
                    <li ><a
                        href="${pageContext.request.contextPath}/ProductServlet?cid=${param.cid }&method=findByCid&currentPage=${i }">${i}</a></li>
                </c:if>

            </c:forEach>
            
            <c:if test="${ pageBean.currentPage != pageBean.totalPage }">
                <li ><a
                    href="${ pageContext.request.contextPath }/ProductServlet?cid=${param.cid }&method=findByCid&currentPage=${pageBean.currentPage+1 }"
                    aria-label="Next"> <span aria-hidden="true">&raquo;</span>
                </a></li>
            </c:if>
        </ul>
    </div>
    <!-- 分页结束=======================        -->