java - 从具有 Main 变量的方法写入文件

Question

我有来自主程序的变量，我想使用私有(private)(或公共(public)并不重要，我将它们保留在同一个类中)方法将它们写入文本文件。我已经完成将它们写入主文件中...我只是不知道如何将主文件中的变量调用到我的 writeToFile() 方法中。以下是我尝试过的，但我不确定如何将两者结合起来。

 //This portion is what I had in my main method that wrote the info to a file successfully 

     //Write to File
             String fileName = "order.txt";
             try{
                 PrintWriter writer = new PrintWriter(fileName);
                 writer.println("Thank you for ordering from Diamond Cards");
                 writer.println("Name: " + customerName);
                 writer.println("Returning Customer: " + customerReturn );
                 writer.println("Phone: " + custNumber);
                 writer.println("Card Type: " + customerType);
                 writer.println("Card Color: " + customerColor);
                 writer.println("Card Coating: " + customerCoat);
                 writer.println("Item Amount: " + numItems);
                 writer.println("Total Cost: " + fmt1.format(totalCostMsg));
                 writer.flush();
                 writer.close();
                 JOptionPane.showMessageDialog(null, "Receipt has been printed"); 
             } catch (FileNotFoundException e) 
                        {e.printStackTrace();
                        System.exit(0) ;         
                        }    
             }


// This is where I try to create a method to do the file writing.... not sure how to proceed..


   public static void writeToFile() {
            try{
                FileWriter fw = new FileWriter("order.text"); //File name to be created
                PrintWriter pw = new PrintWriter (fw);          // Prints to the file that was created
         //text to be printed to file

        // close the writer     
                pw.close();
        // catch errors     
                } catch (IOException e) {
                out.println("Error!");
                }
            }   

我还需要弄清楚如何创建一个单独的方法来读回文件，但我认为如果我能弄清楚这部分，我可以设计它。

Answer 1

您可以通过向方法添加参数来传递对象。如果您需要引用另一个类或方法中的某些内容，只需添加更多参数即可。

我建议您创建一个 Customer 对象，以便可以将其作为单个实体而不是几十个参数传递。

你可以尝试这样的事情:

public class FileWriteExample {
    public static void main(String[] args) {
        String fileName = "order.txt";
        Customer customer; // Customer object...
        int itemCount;
        float totalCost;
        try {
            PrintWriter writer = new PrintWriter(fileName);
            writeToFile(writer, customer, itemCount, totalCost);
            writer.flush();
            writer.close();
            JOptionPane.showMessageDialog(null, "Receipt has been printed");
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            System.exit(0);
        }
    }
    public static void writeToFile(PrintWriter writer, Customer customer,
            int itemCount, float totalCost) {
        Card card = customer.getCard();
        try {
            writer.println("Thank you for ordering from Diamond Cards");
            writer.println("Name: " + customer.getName());
            writer.println("Returning Customer: " + customer.getReturn());
            writer.println("Phone: " + customer.getPhone());
            writer.println("Card Type: " + card.getType());
            writer.println("Card Color: " + card.getColor());
            writer.println("Card Coating: " + card.getCoating());
            writer.println("Item Amount: " + itemCount);
            writer.println("Total Cost: " + fmt1.format(totalCost));
        } catch (IOException e) {
            System.out.println("Error!");
        }
    }
}