将appendFile转换为不会覆盖的文本文件

Question

Im loosing on append method.

I have a program that inputs an information then printing in a text file.

The problem is, I want to append the new input of information into text file too without overwriting, it means that if I rerun the program the information that I encoded will be in the textfile together with the encoded on the last run of the program.

Please help me. Here is the program:

@SuppressWarnings("resource")
public static void main(String[] args) throws IOException
{
   System.out.println("STUDENT INFORMATION");
   System.out.println("-------------------");
   System.out.println("Full Name            :   ");
    Scanner sc = new Scanner(System.in);
    String name = sc.nextLine();
   System.out.println("\nCourse and Year      :   ");
    String yearcourse = sc.nextLine();
   System.out.println("\nStudent Number       :   ");
    String studentnumber = sc.nextLine();
   System.out.println("\nE-mail Address       :   ");
    String eadd = sc.nextLine();
   System.out.println("\nCellphone Number     :   ");
    String cpnumber = sc.nextLine();
   System.out.println("\nGender               :   ");
    String gender = sc.nextLine();
   System.out.println("\nAge                  :   ");
    String age = sc.nextLine();
   System.out.println("\nDate of Birth        :   ");
    String dob = sc.nextLine();
   System.out.println("\nCivil Status         :   ");
    String status = sc.nextLine();
   System.out.println("\nAddress              :   ");
    String address = sc.nextLine();
   System.out.println("\n\n________________________________________________");
   System.out.println("STUDENT INFORMATION");
   System.out.println("\nName             :   " + name + "");
   System.out.println("Year and Course  :   " + yearcourse + "");
   System.out.println("Student Number   :   " + studentnumber + "");
   System.out.println("E-mail Address   :   " + eadd + "");
   System.out.println("Cellphone Number :   " + cpnumber + "");
   System.out.println("Gender           :   " + gender + "");
   System.out.println("Age              :   " + age + "");
   System.out.println("Date of Birth    :   " + dob + "");
   System.out.println("Civil Status     :   " + status + "");
   System.out.println("Address          :   " + address + "");
   System.out.println("");


    File file = new File("Student Information.txt");
    if(!file.exists())
    {
        file.createNewFile();
    }
    try (PrintWriter writer = new PrintWriter(file)){
        BufferedWriter bufferWritter = new BufferedWriter(writer);
        writer.println("\nSTUDENT INFORMATION:");
        writer.println("--------------------");
        writer.println("Name             :   " + name + "");
        writer.println("Year and Course  :   " + yearcourse + "");
        writer.println("Student Number   :   " + studentnumber + "");
        writer.println("E-mail Address   :   " + eadd + "");
        writer.println("Cellphone Number :   " + cpnumber + "");
        writer.println("Gender           :   " + gender + "");
        writer.println("Age              :   " + age + "");
        writer.println("Date of Birth    :   " + dob + "");
        writer.println("Civil Status     :   " + status + "");
        writer.println("Address          :   " + address + "");
        writer.flush();
    }
}

}

In this. if I rerun the program, the text file will just overwrite with the new encoded information. They said to use append bufferwriter . but I'm really lost.

Answer 1

Try to change your code to something like this:

File file = new File("Student Information.txt");
    if(!file.exists())
    {
        file.createNewFile();
    }
    try(PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter(file, true)))) {
        out.println("\nSTUDENT INFORMATION:");
        out.println("--------------------");
        out.println("Name             :   " + name + "");
        out.println("Year and Course  :   " + yearcourse + "");
        out.println("Student Number   :   " + studentnumber + "");
        out.println("E-mail Address   :   " + eadd + "");
        out.println("Cellphone Number :   " + cpnumber + "");
        out.println("Gender           :   " + gender + "");
        out.println("Age              :   " + age + "");
        out.println("Date of Birth    :   " + dob + "");
        out.println("Civil Status     :   " + status + "");
        out.println("Address          :   " + address + "");
}catch (IOException e) {
    // Handle IO exception.
}

This part of the code:

new FileWriter(file,true)

tells it to append when it's set to true, as you can see on the docs .

---

Or you could change your line:

PrintWriter writer = new PrintWriter(file);

To this:

PrintWriter writer = new PrintWriter(new FileWriter(file,true));

Answer 2

instead of this

PrintWriter writer = new PrintWriter(file);

try this

PrintWriter writer= new PrintWriter(new BufferedWriter(new FileWriter(file, true));

See Also

• How to append content to file in Java
• How to append text to an existing file in Java