将值从数据库传递到组合框

Question

 public CarRent() 
{
    initComponents();
    setLocationRelativeTo(null);

    try
    {
     AddItem();
    }
    catch(Exception e)
    {
       e.printStackTrace();
    }




}


public void Conn() throws Exception
{

  Class.forName("com.mysql.jdbc.Driver");
  conn = DriverManager.getConnection(conn1,user,pass);   

}

public void AddItem() throws Exception
{
            String s = "Select Car_Name from Car_Tbl";
            rs = st.executeQuery(s);

            while(rs.next())
            {
                System.out.println(cboCars);
                cboCars.addItem(rs.getString("Car_Name"));
            }



}

Answer 1

试试看

 Resultset rs = st.executeQuery(s)
 While(rs.next())
{
 cboCars.addItem(rs.getString("Car_Name");
}

需要将rs变量初始化为ResultSet。

我也不知道你的代码上面的尝试。应为声明

Statement st = null;
String s = "Select Car_Name from Car_Tbl";

JComboBox carList = new JComboBox(cboCars);

Statement stmt = null;
String q = "select Car_Name from Car_Tbl"
String[] cars ;
int i = 0;
try { 
    stmt = con.createStatement();
    ResultSet rs = stmt.executeQuery(query);
    while(rs.next()) {
    cars[i] = rs.getString("Car_Name");
    i++;
   } catch (SQLException e) {
    }finally{
     if(stmt !=null) { stmt.close();}
   }
}
// Now You have an array populated with cars . Create your combo box with the data

JComboBox carList = new JComboBox(cars);