高手帮忙看看这段程序那里错了，谢谢了！
String amount=codeToString(request.getParameter( "amount "));
String sqlString2= "select * from qicaiTable where e_name= ' "+e_name+ " 'and e_size= ' "+e_size+ " ' ";
try
{ Connection con1;
Statement sql1;
ResultSet rs1;
Class.forName( "com.microsoft.jdbc.sqlserver.SQLServerDriver ");
con1=DriverManager.getConnection( "jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=shangdianDB ", "sa ", " ");
sql1=con1.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_READ_ONLY);
rs1= sql1.executeQuery(sqlString2);
if(rs1.next()){
String temp=rs1.getString( "amount ");
int amount1=Integer.parseInt(temp)-Integer.parseInt(amount);
if(amount1 <0){
out.print( " <script> ");
out.print( "alert( '你输入的数量超过库存量，请重新输入! '); ");
out.print( "window.location.href= '/shd/send.jsp '; ");
out.print( " </script> ");
}
else
sql1.executeQuery( "update qicaiTable set amount= ' "+amount1+ " ' where e_name= ' "+e_name+ " ' ");
}
else{
out.print( " <script> ");
out.print( "alert( '没有你要的商品，请重新输入! '); ");
out.print( "window.location.href= '/shd/send.jsp '; ");
out.print( " </script> ");
}
con1.close();
//response.sendRedirect( "xianshi.jsp ");
}
catch(SQLException e1)
{
out.print(e1);
}
}
%>
当amount1 <0时不执行if()语句，但是当amount> 0时执行 sql1.executeQuery()语句。看了半天了不知道那里错了，请高手指点下！
[解决办法]
if(amount1 <0){
out.print( " <script> alert( '你输入的数量超过库存量，请重新输入! '); </script> ");
}
else
{
sql1.executeQuery( "update qicaiTable set amount= ' "+amount1+ " ' where e_name= ' "+e_name+ " ' ");
}
}
else{
out.print( " <script> alert( '没有你要的商品，请重新输入! '); </script> ");
}
先这样试试，如果正常的话再加跳转语句
