Java如何在文本文件中进行整数值自动增量？ [英] Java how to make integer value auto-increment in text files?

问题描述

文本文件中的示例

1名称年龄

2姓名年龄

3姓名年龄



当我关闭程序并再次保存应该是

1名称年龄

2名称年龄

3名称年龄

4姓名年龄



我尝试过：



i不知道如何制作这是我的进步。

文件文件=新文件（new_member.txt）;

FileWriter fw = new FileWriter （file.getAbsoluteFile（），true）;

BufferedWriter bw = new BufferedWriter（fw）;

bw.write（ID +，+ name +，+ value + ，0+ number +，+ email +，+ member_type +，+ register +，+ monthly +，+ total +，+ Date +\ n）;

bw.close（）;

Example in text file
1 name age
2 name age
3 name age

when i close the program and save again should be
1 name age
2 name age
3 name age
4 name age

What I have tried:

i have no idea how to make it this is my progress.
File file =new File("new_member.txt");
FileWriter fw = new FileWriter(file.getAbsoluteFile(),true);
BufferedWriter bw = new BufferedWriter(fw);
bw.write(ID+","+name+","+value+",0"+number+","+email+","+member_type+","+register+","+monthly+","+total+","+Date+"\n");
bw.close();

推荐答案

想想应用程序应该做什么。至少它需要读取一些数据，修改它并写出更新的信息。所以它应该是这样的：

打开输入文件

读取每行数据并以列表或类似类型存储

接收修改来自用户，或您需要的任何机制

将每条记录写入输出文件



每行数据中的信息需要是在类中定义，以便您可以管理列表中的每个记录。因此，根据每条记录所需的信息定义类。作为起点，您需要以下内容：

Think about what the application is supposed to do. At the very least it needs to read some data, modify it, and write out the updated information. So it should be something like:
Open the input file
Read each line of data and store in a list or similar type
Receive modifications from the user, or whatever mechanism you need
Write each record to the output file

The information in each line of data needs to be defined in a class so you can manage each record in the list. So define the class based on the information needed in each record. As a starting point you need something like:

class Person {
    public int id;
    public string name;
    public int age;
}

根据您的要求添加其他字段。

Add other fields as per your requirements.

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