Java如何基于IO流实现同一文件读写操作

package com.yl.homework.io;
​
import java.io.*;
import java.util.ArrayList;
​
/**
 * （字符流）读取一个文本文件，每行都追加一个“好”，在文件结尾再追加“完毕”。
 */
public class Test3 {
​
  public static void main(String[] args) {
    //文件对象
    File file=new File("H:\\ioText\\homework.txt");
    //字符缓冲流
    BufferedReader bufferedReader=null;
    BufferedWriter bufferedWriter=null;
    //存储读取的内容
    ArrayList<String> arrayList=new ArrayList<>();
    try {
      //打开输入流
      bufferedReader=new BufferedReader(new FileReader(file));
      //存储读取内容
      String content="";
      //读取数据
      while ((content=bufferedReader.readLine())!=null){
        System.out.println(content);
        //每行都追加一个“好”
        content+="好";
        //把内容存入arrayList
        arrayList.add(content);
      }
    } catch (FileNotFoundException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }finally {
      //关闭流
      try {
        bufferedReader.close();
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
    try {
      //打开输出流
      bufferedWriter=new BufferedWriter(new FileWriter(file));
      //遍历arrayList
      for (int i=0;i<arrayList.size();i++){
        //判断是不是最后一行
        if (i==arrayList.size()-1){
          //写数据
          bufferedWriter.write(arrayList.get(i));
          //刷新
          bufferedWriter.flush();
        }else{
          //写数据
          bufferedWriter.write(arrayList.get(i));
          //换行
          bufferedWriter.newLine();
          //刷新
          bufferedWriter.flush();
        }
      }
      //在文件结尾再追加“完毕”
      bufferedWriter.write("完毕");
      //刷新文件
      bufferedWriter.flush();
    } catch (IOException e) {
      e.printStackTrace();
    }finally {
      try {
        //关闭流
        bufferedWriter.close();
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
  }
}