PrintWriter＆File in java

Question

我写了一个程序，允许用户在一个文件中存储多个备忘录。我想出了如何在Java中使用PrintWriter &文件，但是我的问题与我的输出有关。当我在记事本中检查文件时，我只能输入一个备忘录，没有问题&，只有一个备忘录存在。下面的代码：

import java.util.*; 
import java.io.*; 

public class MemoPadCreator{ 

    public static void main(String[] args) throws FileNotFoundException { 

    Scanner input = new Scanner(System.in); 
    boolean lab25 = false; 
    File file = new File("revisedLab25.txt"); 
    PrintWriter pw = new PrintWriter (file); 
    String answer = ""; 

    do{ 
     while(!lab25){ 

     System.out.print("Enter the topic: "); 
     String topic = input.nextLine(); 

     Date date = new Date(); 
     String todayDate = date.toString(); 

     System.out.print("Message: "); 
     String memo = input.nextLine(); 

     pw.println(todayDate + "\n" + topic + "\n" + memo); 
     pw.close(); 

     System.out.print("Do you want to continue(Y/N)?: "); 
     answer = input.next(); 
     } 

    }while(answer.equals("Y") || answer.equals("y")); 

    if(answer.equals("N") || answer.equals("n")){ 
     System.exit(0); 
    } 

    } 
} 

下面是输出：

Enter the topic: I love food! 
Message: Food is life! 
Do you want to continue(Y/N)?: Y 
Enter the topic: Message: 

如何去改变它，以便输出可以让我继续储存的备忘录，直到我告诉它停下来？

Answer 1

try { 
    Files.write(Paths.get("revisedLab25.txt"), ("the text"todayDate + "\n" + topic + "\n" + memo).getBytes(), StandardOpenOption.APPEND); 
}catch (IOException e) { 
    //exception handling 
} 

因为你具有潜在的多次写入为用户增加了输入循环，你可以用一个Try-with-resources try块写操作。试用资源需要在离开试块时关闭文件：

try(PrintWriter pw= new PrintWriter(new BufferedWriter(new FileWriter("revisedLab25.txt", true)))) { 

    do{ 
     while(!lab25){ 

     System.out.print("Enter the topic: "); 
     String topic = input.nextLine(); 

     Date date = new Date(); 
     String todayDate = date.toString(); 

     System.out.print("Message: "); 
     String memo = input.nextLine(); 

     pw.println(todayDate + "\n" + topic + "\n" + memo); 

     System.out.print("Do you want to continue(Y/N)?: "); 
     answer = input.next(); 
     } 

    }while(answer.equals("Y") || answer.equals("y")); 
} 
catch (IOException e) { 
    //exception handling 
}