J2EE问题，想用下面的语句获取数据库的值总是抛出错误String moneystr=rs.getString("money");

type Exception report

message

description The server encountered an internal error () that
prevented it from fulfilling this request.

exception
org.apache.jasper.JasperException: An exception occurred processing JSP page /Manager/transferCheck.jsp at line 41

38: if(cardID1!=null){
39: String sql="select * from user where cardID='"+cardID1+"'";
40: ResultSet rs=stmt.executeQuery(sql);
41: String moneystr=rs.getString("money");
42: Double money= Double.parseDouble(moneystr);
43: Double moneyt= Double.parseDouble(money1);
44: if(rs.next()){

Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:524)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:417)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)

root cause
javax.servlet.ServletException: java.sql.SQLException: Before start of result set
org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:850)
org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:779)
org.apache.jsp.Manager.transferCheck_jsp._jspService(transferCheck_jsp.java:127)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)

String moneystr=rs.getString("money");
42: Double money= Double.parseDouble(moneystr);
43: Double moneyt= Double.parseDouble(money1);
44: if(rs.next()){

如果只有一条记录，要先使用rs.next()，这个是让游标指到第一条记录。但是一般都是多条记录，所以要用while,你现在的情况是用if，如下
if(rs.next()) { // 如果有记录，指向这条记录，然后才能取值。
Double money= Double.parseDouble(moneystr);
Double moneyt= Double.parseDouble(money1);
}

额