我想检查新输入的数据是否已经在表中
代码:
txtNo = new JTextField();
{
try {
Class.forName("com.mysql.jdbc.Driver");
String srcurl1 = "jdbc:mysql://localhost:3306/DB_name";
Connection con = DriverManager.getConnection(srcurl1,"root","paswrd");
Statement stmt1 = con.createStatement();
ResultSet rs1 = stmt1.executeQuery("select No from bank where No='"+txtNo.getText()+"' ");
int ch =rs1.getInt("No");
int ch4= Integer.parseInt(txtNo.getText());
if(ch==ch4) // input 58 == 58
System.out.println("already exits");
}
catch(Exception e)
{
System.out.println("Exception:"+e);
}
}
错误 :
Exception:java.sql.SQLException: Illegal operation on empty result set.