Question

我有来自我的main的变量，我想使用私有（或公共并不重要，我保持它们在同一个类中）方法将它们写入文本文件。我已经完成了将它们写入主文件中的文件...我只是想弄清楚如何从main调用变量到我的writeToFile（）方法。以下是我的尝试，但我不知道如何将两者合并。

 //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制作一个单独的方法来重新读取文件，但我想我可以设计一下，如果我能解决这个问题。

Answer 1

您想要使用参数定义writeToFile，并从main传递它们：

   // Add additional arguments.
   public static void writeToFile(String fileName, String customerName, ...){
       FileWriter fw = new FileWriter(fileName);
       writer.println("Thank you for ordering from Diamond Cards");
             writer.println("Name: " + customerName);
       // Use additional arguments.
   }

来自main：

writeToFile(fileName, customerName, ...);

我同意Polywhirl先生的意见。如果你创建一个包装对象会更干净，虽然我不确定你为此需要getters和setters。

// The types are all String because you did not mention the types in your
// question.
class Customer {
    public String Name;
    public String Return;
    public String Number;
    public String Type;
    public String Color;
    public String Coat;
    public Customer String(String Name, String Return, String Number, String Type, String Color, String Coat) {
        this.Name = Name;
        this.Return = Return;
        this.Number = Number;
        this.Type = Type;
        this.Color = Color;
        this.Coat = Coat;

    }
}

然后，您可以在main中执行以下操作：

Customer c = new Customer(customerName, customerReturn, customerNumber, customerType, customerColor, customerCoat);

在writeToFile方法中，与Polywhirl先生的回答具有相同的签名，您可以直接执行customer.Name等。

Answer 2

您可以通过向方法添加参数来传递对象。如果您需要在另一个类或方法中引用某些内容，只需添加更多参数。

我建议您创建一个Customer对象，以便将其作为单个实体传递而不是几十个参数。

您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!");
        }
    }
}

Answer 3

可能有一些不需要或不可用的字段，如联系号码等。不要发送长列表写入文件，而应考虑使用Joshua Bloch在Effective Java中建议的Builder模式。

使用Main中的变量从方法写入文件

3 个答案: