案例：集合到文件改进版

 

public class TxtToArrayListDemo {
    public static void main(String[] args) throws IOException {
        //创建ArrayList集合对象
        ArrayList<Student> arrayList = new ArrayList<Student>();

        //创建学生对象
        Student s1 = new Student("001","增幅王",20,"东营");
        Student s2 = new Student("002","强化王",21,"dytv");
        Student s3 = new Student("003","神话王",33,"douyu");

        //把学生对象添加到集合中
        arrayList.add(s1);
        arrayList.add(s2);
        arrayList.add(s3);

        //创建字符缓冲流输出对象
        BufferedWriter bw = new BufferedWriter(new FileWriter("myFile\\aabb.txt"));

        //遍历集合，得到每一个学生对象
        for (Student s : arrayList){
            //把学生对象的数据拼接成指定格式的字符串
            StringBuilder sb = new StringBuilder();
            sb.append(s.getSid()).append(",").append(s.getName()).append(",").append(s.getAge()).append(",").append(s.getAddress());
            //调用字符缓冲输出流对象的方法写数据
            bw.write(sb.toString());
            bw.newLine();
            bw.flush();
        }
        //释放资源
        bw.close();
    }
}

运行结果：