如何让我的FileWriter找到下一个可用行而不是写在下面

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class FileWriterExample {
    public static void main(String[] args) {
        String filePath = "path/to/your/file.txt";
        String nextLine = "next line content";

        try {
            FileWriter fileWriter = new FileWriter(filePath, true); // true表示追加写入
            BufferedReader bufferedReader = new BufferedReader(new FileReader(filePath));

            String line;
            boolean foundNextLine = false;

            while ((line = bufferedReader.readLine()) != null) {
                if (line.equals(nextLine)) {
                    foundNextLine = true;
                    break;
                }
            }

            if (!foundNextLine) {
                fileWriter.write(nextLine + "\n");
                fileWriter.flush();
                System.out.println("Successfully wrote the next line.");
            } else {
                System.out.println("Next line already exists.");
            }

            fileWriter.close();
            bufferedReader.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}