ResultSet问题
ResultSet rs1=stmt.executeQuery("select * from book where bno='"+bno+"'");
if(!rs1.next()){out.println("不存在图书编号为"+bno+"的图书");}
else {
if(select.equals("查询")){
ResultSet rs2=stmt.executeQuery("select * from book where bno='"+bno+"'");
我把rs1和rs2都改成rs1,但第二rs1显示为空,为什么?