在jsp下未产生Oracle数据库查询

Question

I would like to retrieve the data in Oracle database. If I use jsp on Tomcat, it has not result, but if I use SQLDeveloper, the result is show. Both sql string are equal.

The sql string is:

String q="SELECT pid, pswd, name, lgnpics FROM users WHERE pid='"+ uid + "' and pswd='" + psw + "'";

The connection, statement and the resultset realization is:

String cs = "jdbc:oracle:thin:@localhost:1521:xe";
Class.forName("oracle.jdbc.OracleDriver");
Connection cn = DriverManager.getConnection(cs, db_user, db_psw);
Statement stmt = cn.createStatement();
ResultSet rs = stmt.executeQuery(q);

If I test it, the resultset is not available, but I know it's a false result.

The connection is ready and if I use a field which doesn't exixts, I get an error, so the statement is ready to use it.

The header of the JSP file is:

%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8" import="java.sql.*,java.io.*,java.util.*"
    session="true"%>
<%@ page import="javax.servlet.http.*,javax.servlet.*"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/sql" prefix="sql"%>

Could anybody help me why?

UPDATE1: The code what I test the result:

if (!rs.next()) {
    out.println("NOK: result set is not available");
} else {
    while (rs.next()) {
        out.write("OK: result is available");
    }
}

Thanks in advance.

Answer 1

just try with this segment:

 boolean more = rs.next(); if (!more) { out.println("NOK: result set is not available"); } else { while (more) { out.write("OK: result is available"); ....... more = rs.next(); } } 

because I believe you can use rs.next() only once as it points out the cursor asap you call it. so it won't reach your while() loop as it is already passed by your if() condition.

Try and see !