在Java中同時讀取和寫入同一文件

Question

我想要的是在文件B中的文件A中寫一個“字符串”，如果它不存在於文件B中，則知道B開頭是空的

BufferedReader bfA=new BufferedReader(new FileReader("A.txt"));
        BufferedReader bfB=new BufferedReader(new FileReader("B.txt"));
        BufferedWriter writerB=new BufferedWriter(new FileWriter("B.txt"));
        String line1,line2;
        boolean bool=false;
        while((line1=bfA.readLine())!=null){
            bfB=new BufferedReader(new FileReader("B.txt"));
            while((line2=bfB.readLine())!=null){

                if(line1.equals(line2)){
                    bool=true;}}

        if(bool==false){
            writerB.write(line1);
        }
        }

問題是，如果文件A中有重復的字符串

Answer 1

遵循JB Nizet的回答，這里有一些偽代碼

readerA, writerB = "", memory = ""
while(readerA.hasNextLine()){
       line = readerA.nextLine()
  if(line isNotPresent in memory){
       add line to memory 
       add line in writerB
   }
}

希望這可以幫助