java - Jbutton 文本文件和数据库问题

Question

我有以下代码，我正在尝试使其工作。我必须读取包含问题的文本文件的内容并将其保存到数据库测试系统中。

我面临的主要问题是它没有插入数据库。我不确定它是否正在读取文本文件。

我已经从 GameDroids 获得了帮助，根据他上面的解释，我设法得到了这个，但现在它不仅插入而且我的上传按钮变得无响应，它现在不会触发任何事件。拜托，我真的需要帮助。
任何帮助将不胜感激。

例如，对于以下问题，我将在我的 Category_questions 中包含:集合，对于我的问题:以下哪一个不是“现实生活”集合的示例？对于我的 quest_opt_a :您在纸牌游戏中持有的纸牌。等等，对于 Correct_option_answer 我应将 d 插入数据库表中。

这就是问题:

Collection 以下哪一个不是“现实生活” Collection 的示例？A。您在纸牌游戏中持有的纸牌。b.您最喜爱的歌曲存储在您的计算机中。C。足球队的球员。d.一本书的页数。

d.

public void actionPerformed(ActionEvent ev)
{
    String file = fileField.getText();

    SetGetQuestionFileName setGet = new SetGetQuestionFileName(file);


    try
    {    
        ConnectToDatabase database = new ConnectToDatabase();

                             // prepare the query
String query = "INSERT INTO questionnaire (category_questions, questions, quest_opt_a,quest_opt_b, quest_opt_c,  quest_opt_d, correct_option_answer ) VALUES (?, ?, ?, ?, ?, ?, ?)"; 

                PreparedStatement preparedStmt = null;
                                    database.getConnection();   
                        preparedStmt = database.getConnection().prepareStatement(query);

        if(ev.getActionCommand().equals("UPLOAD"))
        {
             // JOptionPane.showMessageDialog(null,"File field can't be empty. Try again","ERROR",JOptionPane.INFORMATION_MESSAGE);  

            File filePathString = new File(file);

                // load the file
             Scanner scanner = new Scanner(file);

                 //fis = new FileInputStream(filePathString);

                if(file.length() == 0)
                {
                    JOptionPane.showMessageDialog(null,"File field can't be empty. Try again","ERROR",JOptionPane.INFORMATION_MESSAGE);
                }

                else
                {
                    if(filePathString.exists() && filePathString.isFile())
                    {


                // read the file line by line
                while (scanner.hasNextLine()) 
                    {
                String line = scanner.nextLine();

             String[] questionAnswer = line.split("?");//[ // line.split["?"] will split the line into two strings, right at the ? and put those two strings into an array. 
            String question = questionAnswer[0];  // so [0] will access the first element in that array - the question 
             String[] answers = questionAnswer[1].split(","); // now we split the string after the ? into many strings divided by comma


                        // create the mysql insert preparedstatement

         preparedStmt.setString(1, "JDBC");   
         preparedStmt.setString(2, question);  
         preparedStmt.setString(3, answers[0]);     
         preparedStmt.setString(4, answers[1]);      
         preparedStmt.setString(5, answers[2]);       
            preparedStmt.setString(6, answers[3]);      
         preparedStmt.setString(7, answers[4]);      

             preparedStmt.executeUpdate();


                        }

            //  database.disconnect();
                            JOptionPane.showMessageDialog(null,"File successfuly uploaded","INFORMATION",JOptionPane.INFORMATION_MESSAGE);
                            fileField.setText("");
                }               

        }

        if(!filePathString.exists() && !filePathString.isFile())

                                JOptionPane.showMessageDialog(null,"File coudn't be found. Do check file name.","ERROR",JOptionPane.INFORMATION_MESSAGE);

    }


}

catch(Exception ex)
        {

        }

    if(ev.getActionCommand().equals("LOGOUT"))
        {
            System.exit(0);
        }

    }   

Answer 1

如果需要，您可以使用 ActionListener 扩展您的 JPanel 或 JFrame 或任何其他 View 类，但通常最好为 ActionListener 创建一个单独的类。

public class MyActionListener extends ActionListener{

   String myVariable;

   public MyActionListner(String variableINeedForTheAction){    // pass the parameters you need in the constructor or getter method
      this.myVariable = variableINeedForTheAction;
   }

   @Override
   public void actionPerformed(ActionEvent e) {
         this.myVariable = "actionPerformed";     // then, when the action gets performed you can access that variable
   }
}


public class MyFrame extends JFrame{
   //some code
   JButton myButton = new JButton();
   String text = "";
   MyActionListner buttonListener = new MyActionListener(text);   // instantiate your own action listener class and pass the variables you need for performing the action
   myButton.addActionListener(buttonListener);       // add the listener to some button
}

所有这些都是为了将​​您的 View 与程序中的 Controller 分开。想象一下，您在另一个框架或面板中的某个位置有另一个按钮，并且您希望它执行与此按钮相同的操作，那么您可以简单地注册操作监听器的另一个实例，而无需复制整个代码。

无论如何，我的猜测是您在执行的操作中做了太多工作，并且整个 GUI 变得无响应，因为您正在从光盘读取文件并将其内容放入您的 actionPerformed 方法中的数据库中。

您可以尝试使用线程来处理所有上传/读取/写入内容:

public void actionPerformed(ActionEvent e){
    Thread myThread = new Thread(new Runnable(){
        public void run(){
            System.out.println(Thread.currentThread().getName() + " is running");

            File filePathString = new File(file);
            // load the file
            Scanner scanner = new Scanner(file);
            //... do the reading and writing here

            System.out.println(Thread.currentThread().getName() + " is finished"); 
        }
    }, "Upload Thread");
    myThread.start();
}