关于Servlet的List假分页_servlet假分页-优快云博客

本文链接：https://blog.youkuaiyun.com/wisdom_c_1010/article/details/41518437

本文介绍了一个用于Java项目的自定义分页组件的设计与实现细节，包括如何从List中获取子列表来实现分页功能，以及如何在Web应用中集成该组件进行商品列表的展示与分页操作。

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Page类

import java.util.ArrayList;
import java.util.List;
/**
 * 
 * @ClassName: PageModel 
 * @Description: 从List中获取子list实行分页 
 *
 */
public class Page {
    private int page = 1; // 当前页

    public int totalPages = 0; // 总页数

    private int pageRecorders;// 每页5条数据

    private int totalRows = 0; // 总数据数

    private int pageStartRow = 0;// 每页的起始数

    private int pageEndRow = 0; // 每页显示数据的终止数

    private boolean hasNextPage = false; // 是否有下一页

    private boolean hasPreviousPage = false; // 是否有前一页

    private List list;

    // private Iterator it;

    public Page(List list, int pageRecorders) {
        init(list, pageRecorders);// 通过对象集，记录总数划分
    }
    
    /**
     * 初始化list，并告之该list每页的记录数
     * @param list
     * @param pageRecorders
     */
    public void init(List list, int pageRecorders) {
        this.pageRecorders = pageRecorders;
        this.list = list;
        totalRows = list.size();
        // it = list.iterator();
        hasPreviousPage = false;
        if ((totalRows % pageRecorders) == 0) {
            totalPages = totalRows / pageRecorders;
        } else {
            totalPages = totalRows / pageRecorders + 1;
        }

        if (page >= totalPages) {
            hasNextPage = false;
        } else {
            hasNextPage = true;
        }

        if (totalRows < pageRecorders) {
            this.pageStartRow = 0;
            this.pageEndRow = totalRows;
        } else {
            this.pageStartRow = 0;
            this.pageEndRow = pageRecorders;
        }
    }


    // 判断要不要分页
    public boolean isNext() {
        return list.size() > 5;
    }

    public void setHasPreviousPage(boolean hasPreviousPage) {
        this.hasPreviousPage = hasPreviousPage;
    }

    public String toString(int temp) {
        String str = Integer.toString(temp);
        return str;
    }

    public void description() {

        String description = "共有数据数:" + this.getTotalRows() +

        "共有页数: " + this.getTotalPages() + 

        "当前页数为:" + this.getPage() +

        " 是否有前一页: " + this.isHasPreviousPage() +

        " 是否有下一页:" + this.isHasNextPage() +

        " 开始行数:" + this.getPageStartRow() +

        " 终止行数:" + this.getPageEndRow();

        System.out.println(description);
    }

    public List getNextPage() {
        page = page + 1;

        disposePage();

        System.out.println("用户凋用的是第" + page + "页");
        this.description();
        return getObjects(page);
    }

    /**
     * 处理分页
     */
    private void disposePage() {

        if (page == 0) {
            page = 1;
        }

        if ((page - 1) > 0) {
            hasPreviousPage = true;
        } else {
            hasPreviousPage = false;
        }

        if (page >= totalPages) {
            hasNextPage = false;
        } else {
            hasNextPage = true;
        }
    }

    public List getPreviousPage() {

        page = page - 1;

        if ((page - 1) > 0) {
            hasPreviousPage = true;
        } else {
            hasPreviousPage = false;
        }
        if (page >= totalPages) {
            hasNextPage = false;
        } else {
            hasNextPage = true;
        }
        this.description();
        return getObjects(page);
    }

    /**
     * 获取第几页的内容
     * 
     * @param page
     * @return
     */
    public List getObjects(int page) {
        if (page == 0)
            this.setPage(1);
        else
            this.setPage(page);
        this.disposePage();
        if (page * pageRecorders < totalRows) {// 判断是否为最后一页
            pageEndRow = page * pageRecorders;
            pageStartRow = pageEndRow - pageRecorders;
        } else {
            pageEndRow = totalRows;
            pageStartRow = pageRecorders * (totalPages - 1);
        }

        List objects = null;
        if (!list.isEmpty()) {
            objects = list.subList(pageStartRow, pageEndRow);
        }
        //this.description();
        return objects;
    }

    public List getFistPage() {
        if (this.isNext()) {
            return list.subList(0, pageRecorders);
        } else {
            return list;
        }
    }

    public boolean isHasNextPage() {
        return hasNextPage;
    }


    public void setHasNextPage(boolean hasNextPage) {
        this.hasNextPage = hasNextPage;
    }


    public List getList() {
        return list;
    }


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


    public int getPage() {
        return page;
    }


    public void setPage(int page) {
        this.page = page;
    }


    public int getPageEndRow() {
        return pageEndRow;
    }


    public void setPageEndRow(int pageEndRow) {
        this.pageEndRow = pageEndRow;
    }


    public int getPageRecorders() {
        return pageRecorders;
    }


    public void setPageRecorders(int pageRecorders) {
        this.pageRecorders = pageRecorders;
    }


    public int getPageStartRow() {
        return pageStartRow;
    }


    public void setPageStartRow(int pageStartRow) {
        this.pageStartRow = pageStartRow;
    }


    public int getTotalPages() {
        return totalPages;
    }


    public void setTotalPages(int totalPages) {
        this.totalPages = totalPages;
    }


    public int getTotalRows() {
        return totalRows;
    }


    public void setTotalRows(int totalRows) {
        this.totalRows = totalRows;
    }


    public boolean isHasPreviousPage() {
        return hasPreviousPage;
    }
    
    
    
    public static void main(String args[]) {
        List<String> list = new ArrayList<String>();
        list.add("a");
        list.add("b");
        list.add("c");
        list.add("d");
        list.add("e");
        list.add("f");
        list.add("g");
        list.add("h");
        list.add("h");
        list.add("i");
        list.add("j");
        list.add("k");
        list.add("l");
        list.add("m");
        Page pm = new Page(list, 1);
        
        
        List sublist = pm.getObjects(3);
        for(int i = 0; i < sublist.size(); i++) {
            System.out.println(sublist.get(i));
        }
        //System.out.println("............"+sublist.get(0));
    	

    }

}

HTML页面

<pre name="code" class="html"><% 
<span>	</span>List saleGoodsList = (List) request.getAttribute("subList");
<span>	</span>for (Object list : saleGoodsList) {
<span>	</span>Goods goods = (Goods) list; 
%>
<tr>
<span>	</span><td>
<span>		</span><img  src="<%=goods.getPic_url()%>" width="120px" height="70px">
<span>	</span></td>
<span>	</span><td>
<span>		</span><%=goods.getTitle()%>
<span>		</span><br/>
<span>		</span><%=goods.getPrice()%>
<span>	</span></td>
</tr>
<%
<span>	</span>}
%>

<tr>
   <td>
<span>	</span><a href="saleGoodsList?pageNow=1&pageSize=5" >首页</a>
<span>	</span><c:choose>
<span>	</span><c:when test="${pageNow==1}">
<span>		</span><a href="saleGoodsList?pageNow=1&pageSize=5">上一页</a>
<span>	</span></c:when>
<span>	</span><c:otherwise>
<span>		</span><a href="saleGoodsList?pageNow=${pageNow-1}&pageSize=5">上一页</a>
<span>	</span></c:otherwise>  
<span>	</span></c:choose>
<span>	</span><c:choose>
<span>	</span><c:when test="${pageNow == totalPage}">
<span>		</span><a href="saleGoodsList?pageNow=${totalPage}&pageSize=5">下一页</a>
<span>	</span></c:when>
<span>	</span><c:otherwise>
<span>		</span><a href="saleGoodsList?pageNow=${pageNow+1}&pageSize=5">下一页</a>
<span>	</span> </c:otherwise>  
<span>	</span></c:choose>
<span>	</span><a href="saleGoodsList?pageNow=<%=request.getAttribute("totalPage")%>&pageSize=5">末页</a>
<span>	</span>当前第<%=request.getAttribute("pageNow") %>页 总共<%=request.getAttribute("totalPage") %>页  共<%=request.getAttribute("totalRow") %>条数据
   </td>
</tr>

web.xml

  <servlet>
  	<servlet-name>saleGoodsServlet</servlet-name>
  	<servlet-class>servlet.saleGoodsServlet</servlet-class>
  </servlet>
  <servlet>
  	<servlet-name>storeGoodsServlet</servlet-name>
  	<servlet-class>servlet.storeGoodsServlet</servlet-class>
  </servlet>
  <servlet-mapping>
  	<servlet-name>saleGoodsServlet</servlet-name>
  	<url-pattern>/saleGoodsList</url-pattern>
  </servlet-mapping>
   <servlet-mapping>
  	<servlet-name>storeGoodsServlet</servlet-name>
  	<url-pattern>/storeGoodsList</url-pattern>
  </servlet-mapping>

Servlet类

public void service(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		//设置接受字符类型
		request.setCharacterEncoding("UTF-8");
		//设置输出字符类型
		response.setContentType("text/html;charset=UTF-8");
		TaobaoClient client = new DefaultTaobaoClient(
				"http://gw.api.tbsandbox.com/router/rest", "***",
				"***");
		String saleGoodsResult = TaobaoOpenApiDemo.saleGioodsGet(client);
		List<Goods> saleGoodsList = TaobaoOpenApiDemo
				.changeList(saleGoodsResult);
		//当前页页码
		Integer pageNow = Integer.parseInt(request.getParameter("pageNow"));
		//每页显示条数
		Integer pageSize = Integer.parseInt(request.getParameter("pageSize"));
		//总数据数
		Integer totalRow = saleGoodsList.size();
		//总页数
		Integer totalPage = totalRow % pageSize == 0 ? totalRow / pageSize : totalRow / pageSize + 1;
		//调用Page中List分页方法
		Page pm = new Page(saleGoodsList, pageSize);
		List subList = pm.getObjects(pageNow);
		request.setAttribute("subList", subList);
		request.setAttribute("pageNow", pageNow);
		request.setAttribute("totalRow", totalRow);
		request.setAttribute("totalPage", totalPage);
		//返回页面
		RequestDispatcher rd = request.getRequestDispatcher("saleGoodsList.jsp"); 
		rd.forward(request, response);
	}