如果我在java中使用线程，如何打印到文本文件？

PrintWriter writer = new PrintWriter("output.txt");

synchronized (writer) {
    writer.println("Hello, World!");
}

writer.close();

import java.io.PrintWriter;

public class ThreadExample extends Thread {
    private PrintWriter writer;

    public ThreadExample(PrintWriter writer) {
        this.writer = writer;
    }

    @Override
    public void run() {
        synchronized (writer) {
            writer.println("Hello, World!");
        }
    }

    public static void main(String[] args) {
        try {
            PrintWriter writer = new PrintWriter("output.txt");
            ThreadExample thread = new ThreadExample(writer);
            thread.start();
            thread.join(); // 等待线程结束
            writer.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}