怎么把数据库里面的一列求和,然后把结果取出来显示在jsp页面上?? servlet数据库jsp 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 SELECT SUM(列名) FROM 表名 ,得到总数count把取出来的数据request.setAttribute("count", count);jsp页面 ${requestScope.count } // String sql1="select sum(km) as sumkm from jixiao2";把这个注释打开,执行一下该语句把结果赋值给一个int型变量。然后可以通过2#的方法就能在jsp页面显示! 能具体一点吗?求和完了怎么取出来?然后传递给JSP界面显示出来? 还要更具体?你确定你一楼贴的代码是你自己写的么?我试过了啊,我把注释都打开了,我在这加了两句代码,在之前的包定义了count,eclipse在count那里报错说count cannot be resolved to a variable。代码如下: try { Class.forName("com.mysql.jdbc.Driver"); Connection conn=DriverManager.getConnection(DBURL,DBUSER,DBPASS); ArrayList<Jixiao> list =new ArrayList<Jixiao>(); String sql ="select * from jixiao2"; String sql1="select sum(km) as count from jixiao2"; PreparedStatement pstmt =conn.prepareStatement(sql); Statement stmt=conn.createStatement(); ResultSet rssumkm1=stmt.executeQuery(sql1); ResultSet rs=pstmt.executeQuery(); while(rs.next()) { Jixiao jx=new Jixiao(); jx.setId(rs.getInt(1)); jx.setDay(rs.getString(2)); jx.setClasst(rs.getString(3)); jx.setStarttingtime(rs.getInt(4)); jx.setFinishtime(rs.getInt(5)); jx.setOrigin(rs.getString(6)); jx.setFinish(rs.getString(7)); jx.setStartkm(rs.getInt(8)); jx.setFinishkm(rs.getInt(9)); jx.setKm(rs.getInt(10)); jx.setAllowance(rs.getInt(11)); jx.setCount(rssumkm1.getInt(count)); list.add(jx); } request.setAttribute("Count", count); 怎么获取某一个Java类的实例个数 java导出jar文件无法执行? socket的问题 谁帮我看看这个程序错在那了? 关于static狂论? 请教struts 2,启动tomcat时的错误Unable to load bean 头好痛!是书太乱,还是我太笨? 问一个xml转换的问题,不知有没有知道的 java加壳 有关树节点的问题,请朋友们帮忙解答一下. 为什么我的线程被修改了名字? 看不懂代码里的i++和输出的结果是什么关系
把取出来的数据request.setAttribute("count", count);
jsp页面 ${requestScope.count }
然后可以通过2#的方法就能在jsp页面显示!
我试过了啊,我把注释都打开了,我在这加了两句代码,在之前的包定义了count,eclipse在count那里报错说count cannot be resolved to a variable。代码如下:
try
{
Class.forName("com.mysql.jdbc.Driver");
Connection conn=DriverManager.getConnection(DBURL,DBUSER,DBPASS);
ArrayList<Jixiao> list =new ArrayList<Jixiao>();
String sql ="select * from jixiao2";
String sql1="select sum(km) as count from jixiao2";
PreparedStatement pstmt =conn.prepareStatement(sql);
Statement stmt=conn.createStatement();
ResultSet rssumkm1=stmt.executeQuery(sql1);
ResultSet rs=pstmt.executeQuery();
while(rs.next())
{
Jixiao jx=new Jixiao();
jx.setId(rs.getInt(1));
jx.setDay(rs.getString(2));
jx.setClasst(rs.getString(3));
jx.setStarttingtime(rs.getInt(4));
jx.setFinishtime(rs.getInt(5));
jx.setOrigin(rs.getString(6));
jx.setFinish(rs.getString(7));
jx.setStartkm(rs.getInt(8));
jx.setFinishkm(rs.getInt(9));
jx.setKm(rs.getInt(10));
jx.setAllowance(rs.getInt(11));
jx.setCount(rssumkm1.getInt(count));
list.add(jx);
}
request.setAttribute("Count", count);