Java无法写入.txt

Question

你好，我非常需要你的帮助，我有一个带有 jcombobox 和 3 个文本字段的 jframe，我想要在文本字段中写入的任何内容以及在组合框中所做的选择写入 .txt 我尝试了很多东西，但什么也没有，文件正在创建为 Orders.txt 但仍为空白：S 这是我的代码，我感谢任何帮助，谢谢:)

public class addSalesMan extends JFrame {
    private JComboBox namesJComboBox;
    private JTextField text1;//gia to poso
    private JTextField text2;//thn perigrafh
    private JTextField text3;//kai to numero ths paragelias kai ola auta tha egrafontai sto Orders.txt
    private JButton okJbutton;
    private String names[] = {"Basilis Komnhnos", "Iwanna Papadhmhtriou"};
   public String amount,name,description,number;

    public addSalesMan() {
        super("Προσθήκη παραγγελιών");
        setLayout(new FlowLayout());//dialegoume to flowlayout
//        TextFieldHandler handler = new TextFieldHandler(); writer.write(string);



            //ftiaxonoume to combobox gia tn epilogi tou onomatos
        namesJComboBox = new JComboBox(names);//orizmos JCOMBO BOX
        namesJComboBox.setMaximumRowCount(2);//na emfanizei 2 grammes
                     add(namesJComboBox);
             namesJComboBox.addItemListener(new ItemListener() {
            //xeirozome to simvan edw dhladh tn kataxwrisei ston fakelo         
           public void itemStateChanged(ItemEvent event) {
//prosdiorizoyme an eina epilegmeno to plaisio elegxou
                if (event.getStateChange() == ItemEvent.SELECTED) {                 

                            name = (names[namesJComboBox.getSelectedIndex()]);

//                            writer.newLine();             
                 setVisible(true);
            }
                 }
        });   //telos touComboBOx


        //dimioutgw pediou keimenou me 10 sthles gia thn kathe epilogh kai veveonomaste oti tha mporoume na ta epe3ergasoume kanontas ta editable

        text1 = new JTextField("Amount",10);
add(text1);
        text2 = new JTextField("Description",10);
add(text2);
        text3 = new JTextField("Order Number",10);
add(text3);

        TextFieldHandler handler = new TextFieldHandler();
        text1.addActionListener(handler);
        text2.addActionListener(handler);
        text3.addActionListener(handler);

        //private eswterikh clash gia ton xeirismo twn events twn text
//button kataxwrisis
 okJbutton=new JButton("Καταχώρηση");
 add(okJbutton);
 ButtonHandler bhandler=new ButtonHandler();
 okJbutton.addActionListener(bhandler);

    Order order=new Order(name,amount,description,number);
      Order.addOrders(name,amount,description,number);

    }
    private class ButtonHandler implements ActionListener{
        public void actionPerformed(ActionEvent bevent ){

             JOptionPane.showMessageDialog(addSalesMan.this,String.format("Η Καταχωρηση ήταν επιτυχής",bevent.getActionCommand()));


        }
    }
       private class TextFieldHandler implements ActionListener {
            //epe3ergasia twn simvantwn me kathe enter t xrhsth

            public void actionPerformed(ActionEvent evt) {
                String amount,description,number;
                amount=text1.getText();
                description=text2.getText();
                number=text3.getText();
                text1.selectAll();
                text2.selectAll();
                text3.selectAll();

              }
      if(evt.getSource()==text1 && evt.getSource()==text2 && evt.getSource()==text3){
        JOptionPane.showMessageDialog(addSalesMan.this,String.format("Η Καταχωρηση ήταν επιτυχής",evt.getActionCommand()));

           }
      }

//actionperformed telos
            //ean o xrhsths patisei enter sthn kathe epilogh antistixi kataxwrisi sto

            }


          public static void main(String args[]) {
       java.awt.EventQueue.invokeLater(new Runnable() {
    public void run() {
        new addSalesMan().setVisible(true);
            }
 });
      }
    }

作者在另一个班级。这是相关代码：

public static void addOrders(String name,String amount,String description,String o_number){
    FileOutputStream fout;
    try {
        FileWriter fstream = new FileWriter("Orders.txt");
        if(name!=null){
            BufferedWriter out = new BufferedWriter(fstream);
            out.write(name);
            out.write(amount);
            out.write(description);
            out.write(o_number);
            out.write("\t\n");
            out.close();
        }
    } catch (IOException e) {
        System.err.println ("Unable to write to file");
        System.exit(-1);
    }
}

Answer 1

看来主要问题是您在构造函数中调用 Order.addOrders() 。相反，您应该在用户选择保存其选择时调用它。我假设您希望在用户按下按钮时发生这种情况。因此应该将代码添加到按钮的 ActionListener 中。

您可能需要尝试的是当用户关闭框架时刷新并关闭编写器。

将以下内容添加到框架的构造函数中：

addWindowListener(new WindowAdapter(){
    public void windowClosing(WindowEvent e){
        writer.flush();
        writer.close();
    }
});

当用户关闭框架时，上面的代码将刷新并关闭编写器。

您的代码不清楚，所以我不确定 writer 变量是在哪里声明的，我只是假设它是一个类级别变量。

此外，如果您想向文件添加行而不是每次都覆盖它，则需要以“追加”模式打开文件。这可以通过以下方式实现：

new FileWriter(yourFilePath, true); // set append to true