关于#java#的问题，请各位专家解答！(开发工具-eclipse)

多线程的题目
关于#java#的问题，请各位专家解答！(开发工具-eclipse)

package com.dt.zt.admin;
import java.io.*;
import java.util.Random;
import java.util.Scanner;

public class Test {
    public static void main(String[] args) {
//        randomName("G:\\com_qfedu\\name.txt");
       Fwriter fwriter = new Fwriter("G:\\com_qfedu\\name.txt");
       Fread fread = new Fread("G:\\com_qfedu\\name.txt", fwriter);
        fread.start();
        fwriter.start();
    }
   
    public static void randomName(String fileName){
        //创建字符串数组保存名字
        String[] names = new String[10];
        //创建文件对象
        File file = new File(fileName);
        try {
            BufferedReader bufferedReader = new BufferedReader(new FileReader(file));
            for (int i = 0; i < 10; i++) {
                //按行读取数据
                names[i] = bufferedReader.readLine();
            }

            Random random = new Random();
            for (int i = 0; i < 3; i++) {
                //随机打印名字
                System.out.println(names[random.nextInt(10)]);
                //休眠3秒
                Thread.sleep(3000);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
class Fread extends Thread {
    private String fileName;
    private Thread t;
    public StringBuilder stringBuilder = new StringBuilder();


    public Fread(String fileName, Thread t) {
        this.fileName = fileName;
        this.t = t;

    }
    
    @Override
    public void run() {
        try {
            t.join();
            BufferedReader bufferedReader = new BufferedReader(new FileReader(fileName));
            String str = null;
            while ((str = bufferedReader.readLine()) != null) {
                stringBuilder.append(str);
            }
            System.out.println("stringBuilder = " + stringBuilder);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

class Fwriter extends Thread{
    private String fileName;
  
    public Fwriter(String fileName){
        this.fileName = fileName;
    }

    @Override
    public void run() {
        try {
            BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(fileName, true));
            for (int i = 0; i < 10; i++) {
                bufferedWriter.write("\r\n" + i + Thread.currentThread().getName());
            }
            bufferedWriter.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}