java调用返回一个光标的存储过程出错？

Question

为什么我取不出结果，就是控制台上没有打印任何东西，也没有出什么错。

代码贴上：

create or replace package mypackage as
    type empcursor is ref cursor;
    procedure queryemplist(dno in number,emplist out empcursor);
end mypackage;

create or replace package body mypackage as
    procedure queryemplist(dno in number,emplist out empcursor) as
begin
    open emplist for select * from emp where empno=dno;
    end queryemplist;
end mypackage;

--------------------------------------------------------------------------------------------

public static void main(String[] args) {
        Connection conn = null;
        CallableStatement call = null;
        ResultSet rs = null;
        try {
            String sql = "{call MYPACKAGE.queryemplist(?,?)}";
            conn  = JDBCUtil.getConn();
            call = conn.prepareCall(sql);
            call.setInt(1, 20);
            call.registerOutParameter(2,OracleTypes.CURSOR);
            call.execute();
            rs = ((OracleCallableStatement)call).getCursor(2);
            //rs = (ResultSet) call.getObject(2);
            while(rs.next()){
                int deptno = rs.getInt("deptno");
                String name = rs.getString("ename");
                String job = rs.getString("job");
                double salary = rs.getDouble("sal");
                System.out.println(deptno+"\t"+name+"\t"+job+"\t"+salary);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }