Java 从netbeans中的另一个表单向JTable添加数据

我有这两种表格。一个包含几个按钮。另一个包含两个表。单击一个按钮，数据保存在数据库中，然后以另一种形式传输到JTable。我只通过第一个表单编写代码。但它不起作用。 代码如下：

int dress1=100;
DefaultTableModel CurrPurchases=(DefaultTableModel) CurrentPurchases.getModel();
double price1=Double.parseDouble(Price1.getText());
int rows=CurrPurchases.getRowCount();
if(rows > 0){
    for (int i = 0; i < rows; i++) {
         CurrPurchases.removeRow(0);
    }
}
try{
    Connection connection=getConnection();
    ResultSet curprs=null;
    Statement buy1stmt=connection.createStatement();
    String Buy1Query1="Update Products set Quantity=Quantity-1 where Product_no=1;";
    String Buy1Query2="Insert into Buy values('"+Pname1.getText()+"',"+price1+");";
    buy1stmt.executeUpdate(Buy1Query1);
    buy1stmt.executeUpdate(Buy1Query2);
    dress1--;
    if(dress1==0){
        JOptionPane.showMessageDialog(null,"Sorry, This Item is Out of Stock!");
    }
    new ShoppingCart().setVisible(true);
    PreparedStatement buy2stmt=connection.prepareStatement("Select * from Buy;");
    curprs=buy2stmt.executeQuery();
    if(curprs.last()){
        CurrPurchases.addRow(new Object[]{curprs.getString(1),curprs.getDouble(2)});
    }
}
catch(Exception ex){
    ex.printStackTrace();
}
finally{}

如何以其他形式将数据添加到该表（CurrentBurchases）中？ 注意：我不想在表单中添加任何按钮，我只想显示数据

如有任何帮助，将不胜感激。

来自评论部分：

CurrentPurchases.getModel（）

带红色下划线。事实上

CurrentPurchases

是另一种形式的jtable名称。所以 我现在该怎么办

我现在明白你的问题了。您正试图从另一个窗体直接访问窗体中定义的变量。这就是编译器抱怨的原因。您需要创建此

CurrentPurchases

的公共getter，以便从其他类访问它。大概是这样的：

public JTable getCurrentPurchasesTable() {
    return this.CurrentPurchases;
}

public class Form1 extends JDialog {

    JTable currentPurchases;
    JButton addRecordButton;

    private initComponents() {
        addRecordButton = new JButton("Add record");
        addRecord.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent evt) {
                Form2 form2 = new Form2();
                form2.setForm1(this);
                form2.setVisible(true);
            }
        };
        ... // init the table and other components
    }

    public JTable getCurrentPurchasesTable() {
        return this.currentPurchases;
    }
}

public class Form2 extends JDialog {

    Form1 form1; // this variable will keep reference to a Form1 instance
    JButton saveRecordButton;

    private void initComponents() {
        saveRecordButton = new JButton("Save record");
        saveRecordButton .addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent evt) {
                DefaultTableModel model = (DefaultTableModel) form1.getCurrentPurchasesTable().getModel();
                // add new rocord to the model
            }
        };
        ... // init the other components

    }

    public void setForm1(Form1 f) {
        this.form1 = f;
    }

}

public class Form1 extends JDialog {

    JTable currentPurchases;
    JButton addRecordButton;

    private initComponents() {
        addRecordButton = new JButton("Add record");
        addRecord.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent evt) {
                Form2 form2 = new Form2();
                form2.setTableModel(currentPurchases.getModel());
                form2.setVisible(true);
            }
        };
        ... // init the table and other components
    }
}

public class Form2 extends JDialog {

    TableModel model; // this variable will keep reference to a TableModel instance
    JButton saveRecordButton;

    private void initComponents() {
        saveRecordButton = new JButton("Save record");
        saveRecordButton .addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent evt) {
                // add new rocord to the model:
                ((DefaultTableModel)model).addRow(...);                    
            }
        };
        ... // init the other components

    }

    public void setTableModel(TableModel m) {
        this.model = m;
    }

}

然后进行以下更改：

DefaultTableModel CurrPurchases= (DefaultTableModel) otherFormVariable.getCurrentPurchasesTable().getModel();

当然，您需要引用另一个表单（我在示例中称之为

otherFormVariable

），以便按照您的意愿获取表

---

离题提示：

• 始终尝试跟随。它使人们说同一种语言

---

编辑：实现示例 既然您是Java新手（欢迎来到这个世界：p），我将给您两个可能的实现示例

首先，假设您有两种形式，如下所示：

• Form1

  ：这是您的桌子

• Form2

  ：在这里，您可以将新记录添加到数据库和上一个数据库中 桌子

示例1：允许公众访问Form1的表 第一种方法是你正在尝试的方法。要使其以这种方式工作，您需要执行以下操作：

public JTable getCurrentPurchasesTable() {
    return this.CurrentPurchases;
}

public class Form1 extends JDialog {

    JTable currentPurchases;
    JButton addRecordButton;

    private initComponents() {
        addRecordButton = new JButton("Add record");
        addRecord.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent evt) {
                Form2 form2 = new Form2();
                form2.setForm1(this);
                form2.setVisible(true);
            }
        };
        ... // init the table and other components
    }

    public JTable getCurrentPurchasesTable() {
        return this.currentPurchases;
    }
}

public class Form2 extends JDialog {

    Form1 form1; // this variable will keep reference to a Form1 instance
    JButton saveRecordButton;

    private void initComponents() {
        saveRecordButton = new JButton("Save record");
        saveRecordButton .addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent evt) {
                DefaultTableModel model = (DefaultTableModel) form1.getCurrentPurchasesTable().getModel();
                // add new rocord to the model
            }
        };
        ... // init the other components

    }

    public void setForm1(Form1 f) {
        this.form1 = f;
    }

}

public class Form1 extends JDialog {

    JTable currentPurchases;
    JButton addRecordButton;

    private initComponents() {
        addRecordButton = new JButton("Add record");
        addRecord.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent evt) {
                Form2 form2 = new Form2();
                form2.setTableModel(currentPurchases.getModel());
                form2.setVisible(true);
            }
        };
        ... // init the table and other components
    }
}

public class Form2 extends JDialog {

    TableModel model; // this variable will keep reference to a TableModel instance
    JButton saveRecordButton;

    private void initComponents() {
        saveRecordButton = new JButton("Save record");
        saveRecordButton .addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent evt) {
                // add new rocord to the model:
                ((DefaultTableModel)model).addRow(...);                    
            }
        };
        ... // init the other components

    }

    public void setTableModel(TableModel m) {
        this.model = m;
    }

}

示例2：将TableModel设置为Form2 第二种方法是将

TableModel

设置为

Form2

对象。这样，您就不需要再公开访问您的表了。应该是这样的：

public JTable getCurrentPurchasesTable() {
    return this.CurrentPurchases;
}

public class Form1 extends JDialog {

    JTable currentPurchases;
    JButton addRecordButton;

    private initComponents() {
        addRecordButton = new JButton("Add record");
        addRecord.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent evt) {
                Form2 form2 = new Form2();
                form2.setForm1(this);
                form2.setVisible(true);
            }
        };
        ... // init the table and other components
    }

    public JTable getCurrentPurchasesTable() {
        return this.currentPurchases;
    }
}

public class Form2 extends JDialog {

    Form1 form1; // this variable will keep reference to a Form1 instance
    JButton saveRecordButton;

    private void initComponents() {
        saveRecordButton = new JButton("Save record");
        saveRecordButton .addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent evt) {
                DefaultTableModel model = (DefaultTableModel) form1.getCurrentPurchasesTable().getModel();
                // add new rocord to the model
            }
        };
        ... // init the other components

    }

    public void setForm1(Form1 f) {
        this.form1 = f;
    }

}

public class Form1 extends JDialog {

    JTable currentPurchases;
    JButton addRecordButton;

    private initComponents() {
        addRecordButton = new JButton("Add record");
        addRecord.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent evt) {
                Form2 form2 = new Form2();
                form2.setTableModel(currentPurchases.getModel());
                form2.setVisible(true);
            }
        };
        ... // init the table and other components
    }
}

public class Form2 extends JDialog {

    TableModel model; // this variable will keep reference to a TableModel instance
    JButton saveRecordButton;

    private void initComponents() {
        saveRecordButton = new JButton("Save record");
        saveRecordButton .addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent evt) {
                // add new rocord to the model:
                ((DefaultTableModel)model).addRow(...);                    
            }
        };
        ... // init the other components

    }

    public void setTableModel(TableModel m) {
        this.model = m;
    }

}

---

你面临的错误到底是什么？这是个例外吗？编译错误？如果不知道这个错误，很难帮助你。哦，对不起！我的意思是它用红色下划线，这只是一种警告，而不是一个错误。IDE对这行怎么说？为什么它在抱怨？缺少变量？未知标识符？表达式的开头非法？它说“找不到符号”…然后我怀疑这个导入丢失了：

import javax.swing.table.DefaultTableModel。试试看，让我知道它是怎么回事：）对不起，我是新手，我应该在哪里进入公共getter？不用担心，不需要道歉：）假设您的表位于
Form1
位置。您应该在此表中添加公共访问权限。现在您有了另一个类
Form2
，可以在其中添加数据。因此，第二个必须包含对
Form1
的引用，然后才能调用
Form1.getCurrentPurchasesTable（）.getModel（）。让我知道是否足够清楚：）@Lululalano不确定我是否用了正确的方法，但我只是按照你的指示做了，它显示了一个警告：
非静态方法getCurrentPurchasesTable（）不能从静态上下文引用
…我应该在哪里键入公共getter，我的意思是在哪一行或哪一页？@mKorbel我的魔法球失去了几个小时的连接，但现在我认为它又起作用了：P@LuluLala你得到的新错误是因为你没有保留对
Form1
对象的任何引用。请参阅更新的答案。我已经包括了两个实现示例。希望这些对您有所帮助，并能引导您走上正确的道路：）