分页查询

m页数 n条数 n*m-1   

总页数      如果总条数不可以 整除 当前页数显示的条数  就+1

　　　　  反之整出后的结果就是总页数

上一页  parseInt(获取当前页数)-1 

下一页   parseInt(获取当前页数)+1 

Page实体类

public class Page {
    //当前页面码数
    private String pageNum;
    //当前页码显示几条
    private String pageSize;
    //总条数
    private int pageCount;
    //结果集
    private ResultSet rs;
    //将结果集放入list集合
    private List list;

    public List getList() {
        return list;
    }

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

    public int getPageCount() {
        return pageCount;
    }

    public void setPageCount(int pageCount) {
        this.pageCount = pageCount;
    }

    public ResultSet getRs() {
        return rs;
    }

    public void setRs(ResultSet rs) {
        this.rs = rs;
    }

    public String getPageNum() {
        return pageNum;
    }

    public void setPageNum(String pageNum) {
        this.pageNum = pageNum;
    }

    public String getPageSize() {
        return pageSize;
    }

    public void setPageSize(String pageSize) {
        this.pageSize = pageSize;
    }
}

Dao层

public interface SelectDao {public Page selectPage(Page page);
}

public class SelectDaoImpl extends BaseDao implements SelectDao {
  
    @Override
    public Page selectPage(Page page) {
        String sql = "SELECT `id`,`title`,`createDate`  FROM `news_detail` ";
        Page page1 = this.page(sql,page);
        return page1;
    }
//
}

public interface SelectService {
// 示例  public 返回值类型（int、Boolean,String）方法名（userLogin）( 括号里写 参数类型 和 参数名 示例 String name);
public List selectAll();
public Page selectPage(Page page);
}

public class SelectServiceImpl implements SelectService{
    @Override
    public Page  selectPage(Page page) {
        SelectDao selectDao = new SelectDaoImpl();
        Page page1 = selectDao.selectPage(page);
        ResultSet rs = page1.getRs();
        List newsList = new ArrayList();
        try {
            while (rs.next()){
                NewsDetail newsDetail = new NewsDetail();
                int id = rs.getInt("id");
                String title = rs.getString("title");
                Date createDate = rs.getTimestamp("createDate");
                newsDetail.setId(id);
                newsDetail.setTitle(title);
                newsDetail.setCreateDate(createDate);

                newsList.add(newsDetail);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }

        page1.setList(newsList);
        page1.setRs(null);
        return page1;
    }
//
}

Servlet

@WebServlet(name = "SelectServlet", urlPatterns = "/SelectServlet")
public class SelectServlet extends javax.servlet.http.HttpServlet {
    protected void doPost(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws javax.servlet.ServletException, java.io.IOException {
        request.setCharacterEncoding("UTF-8");  // 处理post请求乱码问题
        doGet(request, response);
    }

    protected void doGet(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws javax.servlet.ServletException, java.io.IOException {
        response.setContentType("text/html;charset=UTF-8"); // 处理响应乱码问题:字节流需getBytes("UTF-8")
        // str = new String(str.getBytes("ISO-8859-1"), "UTF-8");   // 处理get请求乱码问题

        // response.getWriter().write("你好 servlet!");
        String opr = request.getParameter("opr");
      if("selectPage".equals(opr)){
            String pageNum = request.getParameter("pageNum");
            //如果页数为空或者为0 默认 显示第一页
            if(pageNum==null||pageNum==""||"0".equals(pageNum)){
                pageNum="1";
            }
            String pageSize = "1";
            Page page =new Page();
            page.setPageNum(pageNum);
            page.setPageSize(pageSize);
            SelectService selectService = new SelectServiceImpl();
            Page page1 =selectService.selectPage(page);


            String newsJSON = JSON.toJSONStringWithDateFormat(page1,"yyyy-MM-dd HH:mm:ss",SerializerFeature.WriteMapNullValue,SerializerFeature.WriteNullStringAsEmpty,SerializerFeature.WriteNullListAsEmpty,SerializerFeature.WriteNullNumberAsZero);

            PrintWriter out = response.getWriter();
            out.print(newsJSON);
            out.flush();
            out.close();
        }
    }
}

jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8" isELIgnored="false" %>

<%
    String info = (String)request.getAttribute("info");
%>

<!DOCTYPE HTML>
<html>
  <head>
    <title>My JSP 'doUserCreate.jsp' starting page</title>
    
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <link rel="stylesheet" type="text/css" href="/css/common.css">
      <script type="text/javascript" src="js/jquery-1.12.4.js"></script>
      <script type="text/javascript">
          $(function (){
              page(1);

              $("#bId").click(function () {
                  var pageNum =$("#pageId").val();
                  page(pageNum);
              });
              $("#backId").click(function () {

                  $(this).attr("page", $("#numId").text()-1);
                  var pageNum= $(this).attr("page");
                  page(pageNum);
              })
              $("#nextId").click(function () {

                  $(this).attr("page", parseInt($("#numId").text())+1);
                  var pageNum= $(this).attr("page");
                  page(pageNum);
              })
              $("#firstId").click(function () {
                  page(1);
              })

              function page(pNum) {
                  var pageNum = pNum;
//                  alert(pageNum);
                  $.getJSON("/SelectServlet","opr=selectPage&pageNum="+pageNum,callBack);
                  function callBack(data) {
                      $("#uId").empty();
//                      alert(data.list);
                      $(data.list).each(function () {

                          $("#uId").append("<li>
" +
                              "                                <span>"+this.createDate+"</span>
" +
                              "                                <a href="/NewsServlet?id="+this.id+"&opr=selectById">"+this.title+"</a>
" +
                              "                            </li>")
                      })
                      $("#countId").text(data.pageCount);
                      $("#numId").text(data.pageNum);
                  }
              }
          } )

      </script>

  </head>
<body>
<%--<%!String  name = "恰同学少年";%>--%>

<%--<%=name%>--%>

<c:set value="pageName" var="name" scope="page"></c:set>
<c:set value="requestName" var="name" scope="request"></c:set>
${requestScope.name}
<%--<c:remove var="name" scope="page"></c:remove>--%>
${pageScope.name}
<!--页面顶部-->
<div id="header">
    <input type="hidden" id = "infoid" value="<%=info%>">
    <div class="main-top">
        <div class="logo"><a href=""><span>新闻大视野</span></a></div>
        <div class="login-box">
            <form action="/NewsServlet?opr=selectAll" method="post">
                <label>用户名</label><input type="text" name="uname" /><label>密码</label>
                <input type="text" name="upassword" /><button>登录</button>
                <input type="submit" value="登录">
            </form>

        </div>
        <div class="nav">
            <ul class="clearfix">
                <li><a href="#">首页</a></li>
                <li><a href="#">国内</a></li>
                <li><a href="#">国际</a></li>
                <li><a href="#">娱乐</a></li>
                <li><a href="#">军事</a></li>
            </ul>
        </div>
    </div>
    <!--banner-->
    <div class="main-banner">
    <img src="/images/banner.png" />
    </div>
    <!--搜索横框-->
    <div class="search-box">
        <div class="sl">
            <div class="sr clearfix">
            
                <span class="left-search clearfix">
                    <label>站内搜索</label><input type="text" name="keyword" value="关键词" /><button class="go-btn"></button>
                </span>
                <span class="right-link">
                    <label>快速链接</label><select><option>-----专题选择-----</option></select><button class="go-btn"></button>
                </span>
                
            </div>
        </div>    
    </div>
</div>
<!--d页面主体-->
<div id="content" class="main-content clearfix">
    <!--主体的的左边部分-->
    <div class="main-content-left">
        <!--新闻专题分类-->
        <div class="class-box">
            <div class="class-box-header">
               <span class="fr"><a href="#">更多...</a></span>
               <h3>新闻专题</h3>
            </div>
            <div class="class-box-content">
                <ul>
                     <li><a href="#">国内</a></li>
                    <li><a href="#">国际</a></li>
                    <li><a href="#">娱乐</a></li>
                    <li><a href="#">军事</a></li>
                    <li><a href="#">财经</a></li>
                    <li><a href="#">天气</a></li>
                    <li class="clear-bottom-line"><a href="#">科技</a></li>
                </ul>
            </div>
        </div>
        <!--最新新闻-->
        <div class="left-box">
            <div class="left-box-tbg">
                <div class="left-box-bbg">
                    <div class="left-box-header"><h3><a href="#">最新新闻</a></h3></div>
                    <div class="left-box-content">
                        <ul>
                            <li><a href="#">课工场最靠谱的互联网教育 Java Web从入门到成就！</a></li>
                            <li><a href="#">课工场最靠谱的互联网教育 Java Web从入门到成就！</a></li>
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                        </ul>
                    </div>
                </div>
            </div>
        </div>
        <!--最新评论-->
        <div class="left-box">
            <div class="left-box-tbg">
                <div class="left-box-bbg">
                    <div class="left-box-header"><h3>最新评论</h3></div>
                    <div class="left-box-content">
                        <ul>
                            <li><a href="#">课工场最靠谱的互联网教育 Java Web从入门到成就！</a></li>
                            <li><a href="#">课工场最靠谱的互联网教育 Java Web从入门到成就！</a></li>
                            <li><a href="#">课工场最靠谱的互联网教育 Java Web从入门到成就！</a></li>
                        </ul>
                    </div>
                </div>
            </div>
        </div>
    </div>
    <!--页面主体的右部，包括新闻的列表和评论内容 -->
    <div class="main-content-right">
        <!--各专题的新闻列表-->
        <div class="main-text-box">
            <div class="main-text-box-tbg">
                <div class="main-text-box-bbg">
                    
                    <div class="main-text-box-header">
                        <h3>即时新闻</h3>
                    </div>
                    <div class="main-text-box-content">
                      <ul class="news-list-ul clearfix" id ="uId">
                            <%--输出--%>
                          <%--<li><span>${newsList[0].createdate}</span><a href="#">${newsList[0].title}</a></li>--%>




                      </ul>
                    </div>
                    <!--图片新闻-->
                    <div class="news-pic">
                        <dl>
                            <dt><img src="/images/new-1.png" /></dt>
                            <dd>PHP从入门到放弃</dd>
                        </dl>
                        <dl>
                            <dt><img src="/images/new-2.png" /></dt>
                            <dd>Java Web从绝望到希望</dd>
                        </dl>
                        <dl>
                            <dt><img src="/images/new-3.png" /></dt>
                            <dd>课工场五一回馈</dd>
                        </dl>
                        <dl>
                            <dt><img src="/images/new-2.png" /></dt>
                            <dd>Java Web从绝望到希望</dd>
                        </dl>
                    </div>
                    <div class="page-bar">
                        <ul class="page-num-ul clearfix">
                            <li><a href="javascript:;" id="firstId">首页</a><li>
                            <li><a href="javascript:;" id="backId" page="">上一页</a><li>
                            <%--<li><a href="#" class="thisclass">1</a><li>--%>
                            <%--<li><a href="#">2</a><li>--%>
                            <%--<li><a href="#">3</a><li>--%>
                            <%--<li><a href="#">4</a><li>--%>
                            <%--<li><a href="#">5</a><li>--%>
                                当前页<span id="numId"></span>/总页数:<span id="countId"></span>
                            <li><a href="javascript:;" id="nextId">下一页</a><li>

                        </ul>

                        <span class="page-go-form"><label>跳转至</label><input id="pageId" type="text" name="numkey" class="page-key" />页<button id="bId" type="submit" class="page-btn">GO</button></span>
                    </div>
                </div>
            </div>
        </div>
        <!--合作媒体-->
        <div class="main-text-box">
            <div class="main-text-box-tbg">
                <div class="main-text-box-bbg">
                    <div class="main-text-box-header">
                        <h3>合作媒体</h3>
                    </div>
                    <div class="main-text-box-content">
                      <ul class="link-text-ul clearfix">
                        <li><a href="#">中国政府网</a></li>
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                      </ul>
                    </div>
                </div>
            </div>
        </div>
    </div>
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