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2019.02.27（java中的真假分页）

作者：互联网

真假分页

真分页

代码案例

SELECT * from user LIMIT 3,3

运行结果：
在这里插入图片描述
代码格式：
select * from user limit 起点,步长
记录的起点默认从0开始

假分页

第一步：
编写panger类，类中包含首页，尾页，总页数，总记录数，每页显示记录数，当前页

public class Panger {
    int start;
    int end;
    int pangerNow;
    int total;
    int pageSize;
    int sum;

    public Panger(int start, int end, int pangerNow, int total, int pageSize,int sum) {
        this.start = start;
        this.end = end;
        this.pangerNow = pangerNow;
        this.total = total;
        this.pageSize = pageSize;
        this.sum = sum;
    }

    public int getSum() {
        return sum;
    }

    public void setSum(int sum) {
        this.sum = sum;
    }

    public int getStart() {
        return start;
    }

    public void setStart(int start) {
        this.start = start;
    }

    public int getEnd() {
        return end;
    }

    public void setEnd(int end) {
        this.end = end;
    }

    public int getPangerNow() {
        return pangerNow;
    }

    public void setPangerNow(int pangerNow) {
        this.pangerNow = pangerNow;
    }

    public int getTotal() {
        return total;
    }

    public void setTotal(int total) {
        this.total = total;
    }

    public int getPageSize() {
        return pageSize;
    }

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

第二步：编写前端界面

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<table border="1px">
    <tr>
        <th>uid</th>
        <th>username</th>
        <th>age</th>
        <th>hobby</th>
    </tr>
    <%--jsp循环展示数据--%>
    <c:forEach items="${list}" var="user">
        <tr>
            <td>${user.uid}</td>
            <td>${user.username}</td>
            <td>${user.age}</td>
            <td>${user.hobby}</td>
        </tr>
    </c:forEach>
</table>
 <%--上传和接收分页数据--%>
第${page.pangerNow}页/共${page.sum}页<a href="ds?pageNow=${page.start}">首页</a><a href="ds?pageNow=${page.pangerNow - 1}">上一页</a>${page.pangerNow}<a href="ds?pageNow=${page.pangerNow + 1}">下一页</a><a href="ds?pageNow=${page.end}">尾页</a>
</body>
</html>

第三步：编写servlet

public class DemoServlet extends javax.servlet.http.HttpServlet {
    protected void doPost(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws javax.servlet.ServletException, IOException {

    }

    protected void doGet(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws javax.servlet.ServletException, IOException {
    	//设置编码格式
        request.setCharacterEncoding("utf-8");
        response.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=utf-8");
        //查询数据库并接受数据
        DBUtil db = new DBUtil();
        String sql = "select * from user";
        Object[] obj = {};
        ResultSet rs = db.select(sql, obj);
        List<User> list = new ArrayList<>();
        try {
            while (rs.next()){
                int uid = rs.getInt(1);
                String username = rs.getString(2);
                int age = rs.getInt(3);
                String hobby = rs.getString(4);
                User user = new User(uid,username,age,hobby);
                list.add(user);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        //接收前端数据，当前页面的显示页数
        String pageNow = request.getParameter("pageNow");
        //设置页面属性
        int start = 1;
        int total = list.size();
        int pageSize = 3;
        int sum;
        if(total % pageSize == 0){
            sum = total / pageSize;
        }else{
            sum = total / pageSize + 1;
        }
        int end = sum;
        int pangerNow = 1;
        if(pageNow != null && !pageNow.equals("")){
            int pageNow1 = Integer.parseInt(pageNow);
            if(pageNow1 < 1){
                pangerNow = 1;
            }else if(pageNow1 > end){
                pangerNow = end;
            }else{
                pangerNow = pageNow1;
            }
        }
        //设置每页显示的数据
        List<User> list1 = new ArrayList<>();
        for (int i = (pangerNow - 1)*pageSize; i < pangerNow*pageSize; i++) {
            if(i == list.size()){
                break;
            }else{
                list1.add(list.get(i));
            }
        }
        Panger page = new Panger(start,end,pangerNow,total,pageSize,sum);
        //传输数据，跳转页面
        request.setAttribute("list",list1);
        request.setAttribute("page",page);
        request.getRequestDispatcher("index1.jsp").forward(request,response);
    }
}

标签：pangerNow,27,java,pageSize,int,sum,2019.02,total,public
来源： https://blog.csdn.net/qq_34191426/article/details/88043751