丛控制台输入两个数字，将相加的结果存入一个文本文件中，怎么做？

package com.estarsh.test;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.InputStreamReader;
import java.util.Scanner;

public class Test11 {
private Scanner sc;

private String readString() {
sc = new Scanner(System.in);
return sc.next();
}

private int readInt() {
sc = new Scanner(System.in);
return sc.nextInt();
}

public String add() {
int int1 = this.readInt();
int int2 = this.readInt();
int resultInt = int1 + int2;
String s = "您输入的第一个数字是：" + int1 + "；您输入的第二个数字是：" + int2 + "；两个数字的和是："
+ resultInt;
System.out.println(s);
return s;
}

public static void main(String[] args) {
Test11 t = new Test11();
try {