Java如何创建，打开，写入和读取然后关闭文件

Question

so here's the problem, i stack on how to create, open, write, and read file, with this code

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

class class_Name{

Formatter x;                       // Variable: creating new file
File file = new File("file.txt");  // Variable: check file existence

    //creating txt file
    public void creating_file(){
        try{
            x = new Formatter("file.txt");
        }catch(Exception e){
            System.out.println("you got an error");
        }
    }

    public int check_file(){
        if(file.exists()){
            return 1; // in main method, check if file already exists just pass from creating file
        }else{
            return 0; // in main method if return value 0, then it create new file with "public void creating_file()" method
        }
    }

so the problem is when i tried to write something in the file, i using class Formatter and it always format all the text data that in it before and class Formatter won't work if public int check_file() is equals to 1 because it skip from creating file using Formatter class and can't just write in the file because variable x undefined

this is the code how i write text in a file

    public void recording_to_file(){
        x.format(format, args); 
    }

and to closing file i need to handle error like this

    public void close_file(){
        try{
            x.close();
        }catch(Exception e){
            file.close();
        }
    }

}

there was just ton of class that i need to do something with just one file, or maybe there was one simple class that can do all in one like(write, open, read, close), i am new in java, i think maybe in here i can get help, thank you

Answer 1

Take a look at this. The second argument to the FileWriter costructor (true) tells it to only append data, instead of overwriting any.

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

class SomeClass{

    Formatter x;                       
    File file = new File("file.txt");  

    public void creating_file(){
        try{
            x = new Formatter(new FileWriter(file, true));
        }catch(Exception e){
            System.out.println("you got an error");
        }
    }

    public boolean check_file(){
        return file.exists();
    }
}