//注册 public Student regedit(String stuNo, String stuPass){ Student regeditStudent = null;//表示注册的学生对象，假设注册失败，所以是null //如果学生没有重复的，那么将学生信息注册到D://students.txt文件 File file = new File(STUDENT_MESS_PATH); if (file.length() == 0) { // 判断文件是否为空 Student student = new Student(stuNo,stuPass); students.add(student); IOUtils ioUtils = new IOUtils(); ioUtils.writerFileByXuLie(regeditStudent,STUDENT_MESS_PATH,true);//将学生信息写入文件 regeditStudent = student; } else { IOUtils ioUtils = new IOUtils(); ArrayList<Student> students = (ArrayList<Student>) ioUtils.readFileByXuLie(STUDENT_MESS_PATH); boolean isCHongFu = false;//没重复 for (Student everyStudent:students ) { if (everyStudent.getStuNo().equals(stuNo) && everyStudent.getStuPass().equals(stuPass)) { isCHongFu = true; regeditStudent = everyStudent; break; } } if (!isCHongFu) { Student student = new Student(stuNo,stuPass); students.add(student); ioUtils.writerFileByXuLie(regeditStudent,STUDENT_MESS_PATH,true);//将学生信息写入文件 regeditStudent = student; } } return regeditStudent; }补全

代码如下：

public Student regedit(String stuNo, String stuPass) {
    Student regeditStudent = null;//表示注册的学生对象，假设注册失败，所以是null
    //如果学生没有重复的，那么将学生信息注册到D://students.txt文件
    File file = new File(STUDENT_MESS_PATH);
    if (file.length() == 0) { // 判断文件是否为空
        Student student = new Student(stuNo,stuPass);
        students.add(student);
        IOUtils ioUtils = new IOUtils();
        ioUtils.writerFileByXuLie(students, STUDENT_MESS_PATH, true);//将学生信息写入文件
        regeditStudent = student;
    }
    else {
        IOUtils ioUtils = new IOUtils();
        ArrayList<Student> students = (ArrayList<Student>) ioUtils.readFileByXuLie(STUDENT_MESS_PATH);
        boolean isCHongFu = false;//没重复
        for (Student everyStudent : students) {
            if (everyStudent.getStuNo().equals(stuNo) && everyStudent.getStuPass().equals(stuPass)) {
                isCHongFu = true;
                regeditStudent = everyStudent;
                break;
            }
        }
        if (!isCHongFu) {
            Student student = new Student(stuNo,stuPass);
            students.add(student);
            ioUtils.writerFileByXuLie(students, STUDENT_MESS_PATH, true);//将学生信息写入文件
            regeditStudent = student;
        }
    }
    return regeditStudent;
}

注释：修正了将学生信息写入文件时，写入了错误的对象和变量名的问题。另外，也将是否有重复的判断逻辑进行了修正，使其更加合理。