时间:2021-07-01 10:21:17 帮助过:55人阅读
计算确定数据表一共分几页:101/pageSize=100/10=10页。rows = select count(1) from users;方法1:pageCount = rows/pageSize + (rows%pageSize==0?0:1); 方法2:pageCount = (rows+ (pageSize-1))/(pageSize);public void doGet(HttpServletRequest req,
计算确定数据表一共分几页:
101/pageSize=100/10=10页。
rows = select count(1) from users;
方法1:pageCount = rows/pageSize + (rows%pageSize==0?0:1);
方法2:pageCount = (rows+ (pageSize-1))/(pageSize);
public void doGet(HttpServletRequest req, HttpServletResponse response)
throws ServletException, IOException {
//第一步:定义每页显示多少行
int pageSize = 10;
try{
//第二步:获取数据表中有多少行
QueryRunner run = new QueryRunner(DataSourceUtils.getDatasSource());
String sql = "select count(*) from users";
Object o = run.query(sql,new ScalarHandler());
int rows = Integer.parseInt(o.toString());
//第三步:计算一共分多少页
int pageCount= rows/pageSize+(rows%pageSize==0?0:1);
//将页数放到req
req.setAttribute("pageCount",pageCount);
}catch(Exception e){
e.printStackTrace();
}
//转发到
req.getRequestDispatcher("/jsps/show.jsp").forward(req, response);
}
用户请求的面码 |
start |
算法: |
1 |
Limit 0,pageSize |
Start = (currentPage-1)*pageSize |
2 |
Limit 10,pageSize |
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3 |
Limit 20,pageSize |
每个页面,最多显示10个页码
pageNum=10;
startNo
endNo
当前页码 |
页码范围 |
算法 |
1 |
1~10 |
If(currentPage<=pageNum/2) 1~10 |
2 |
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3 |
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4 |
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5 |
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6 |
2~11 |
6-4=2 = 6-(pageNum/2-1)=2 = startNo endNo = startNo+(pageNum-1)=11 |
7 |
3~12 |
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8 |
4~13 |
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9 |
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10 |
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11 |
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11-4 = 7 endNo = 7+9=16 endNo = 11; startNo = 2 = endNo-(pageNum-1);
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