Java 如何使用oop概念传递具有不同数据类型的ArrayList对象?
我正在尝试使用ArrayList将值传递给数据库。 然后我得到了一个异常Java 如何使用oop概念传递具有不同数据类型的ArrayList对象?,java,oop,arraylist,Java,Oop,Arraylist,我正在尝试使用ArrayList将值传递给数据库。 然后我得到了一个异常java.lang.ClassCastException:java.lang.String不能转换为model.OrderModel 以下是我如何通过用户获取值 有人能帮我检查一下吗 DefaultTableModel dtm = (DefaultTableModel) tblOrder.getModel(); int numRow = dtm.getRowCount(); int numCol = dtm.
java.lang.ClassCastException:java.lang.String不能转换为model.OrderModel
以下是我如何通过用户获取值 有人能帮我检查一下吗
DefaultTableModel dtm = (DefaultTableModel) tblOrder.getModel();
int numRow = dtm.getRowCount();
int numCol = dtm.getColumnCount();
try {
ArrayList<OrderModel> list = new ArrayList<OrderModel>();
for(int l = 0;l<numRow;l++){
for(int j=0;j<numCol;j++){
list.add((OrderModel) tblOrder.getValueAt(l, j));//this line may be the problem as i think
}
}
Order or = new Order();
or.passingValuesToDB(list);
} catch (Exception e) {
e.printStackTrace();
}
}
(OrderModel)tblOrder.getValueAt(l,j)
是问题所在
ValueAt(l,j)
返回字符串(表列数据类型)。不能将String
强制转换为OrderModel
对象。它们是完全不同的对象。您应该使用行-列值创建一个OrderModel
对象。您可以使用setter或直接传递给构造函数。然后您可以将其添加到ArrayList列表中
ArrayList<OrderModel> list = new ArrayList<OrderModel>();
for (int l = 0; l < numRow; l++) {
int orderid = Integer.parseInt(tblOrder.getValueAt(l, 0).toString());
String customername = tblOrder.getValueAt(l, 1).toString();
String item = tblOrder.getValueAt(l, 2).toString();
double qty = Double.parseDouble(tblOrder.getValueAt(l, 3).toString());
double amount = Double.parseDouble(tblOrder.getValueAt(l, 4).toString());
double total = Double.parseDouble(tblOrder.getValueAt(l, 5).toString());
// OrderModel object
OrderModel ormod1 = new (orderid, customername, item, bla..bla..);
//then add OrderModel to the list
list.add(ormod1);
}
ArrayList list=new ArrayList();
对于(int l=0;l
如果您发布该类和stacktrace,您的tblOrder中有什么内容将很有帮助。您确定tblOrder包含OrderModel
实例吗?tblOrder仅包含(itemName、Qty、price、amount)
public class OrderModel {
private int orderid;
private String customername;
private String item;
private double qty;
private double amount;
private double total;
public OrderModel(int orderid,String customername,String item,Double qty,Double amount,Double total){
this.orderid = orderid;
this.customername = customername;
this.item = item;
this.qty = qty;
this.amount=amount;
this.total=total;
}
public OrderModel() {
throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
public int getOrderid() {
return orderid;
}
public void setOrderid(int orderid) {
this.orderid = orderid;
}
public String getCustomername() {
return customername;
}
public void setCustomername(String customername) {
this.customername = customername;
}
public String getItem() {
return item;
}
public void setItem(String item) {
this.item = item;
}
public double getQty() {
return qty;
}
public void setQty(double qty) {
this.qty = qty;
}
public double getAmount() {
return amount;
}
public void setAmount(double amount) {
this.amount = amount;
}
public double getTotal() {
return total;
}
public void setTotal(double total) {
this.total = total;
}
}
ArrayList<OrderModel> list = new ArrayList<OrderModel>();
for (int l = 0; l < numRow; l++) {
int orderid = Integer.parseInt(tblOrder.getValueAt(l, 0).toString());
String customername = tblOrder.getValueAt(l, 1).toString();
String item = tblOrder.getValueAt(l, 2).toString();
double qty = Double.parseDouble(tblOrder.getValueAt(l, 3).toString());
double amount = Double.parseDouble(tblOrder.getValueAt(l, 4).toString());
double total = Double.parseDouble(tblOrder.getValueAt(l, 5).toString());
// OrderModel object
OrderModel ormod1 = new (orderid, customername, item, bla..bla..);
//then add OrderModel to the list
list.add(ormod1);
}