Question

我的两个toString（）＆＃s;似乎处于无限循环中，但我不确定问题是什么。我现在已经调试了好几个小时了，看不出任何错误。

对于上下文，主要的相关部分是：的System.out.println（1类）; adminStaff1.assignInstructor（class1，instructor1）; 的System.out.println（1类）;

第一个println有效，但是当我调试时，我会看到一个源查找错误，然后才能通过。第二个class1创建StackOverflowError，它是：

Exception in thread "main" java.lang.StackOverflowError
at java.lang.AbstractStringBuilder.append(Unknown Source)
at java.lang.StringBuilder.append(Unknown Source)
at java.lang.StringBuilder.<init>(Unknown Source)
at Instructor.toString(Instructor.java:59)
at java.lang.String.valueOf(Unknown Source)
at java.lang.StringBuilder.append(Unknown Source)
at Class.toString(Class.java:89)
at java.lang.String.valueOf(Unknown Source)
at java.lang.StringBuilder.append(Unknown Source)
at java.util.AbstractCollection.toString(Unknown Source)
at java.lang.String.valueOf(Unknown Source)
at java.lang.StringBuilder.append(Unknown Source)
at Instructor.toString(Instructor.java:59)

Class的toString是：

@Override
public String toString() {
    return "Class [instructor=" + instructor + ", lectureHall="
            + lectureHall + ", currentEnrollment=" + currentEnrollment
            + ", timeSlot=" + timeSlot + ", filled=" + filled
            + ", studentList=" + studentList + "]";
}

教师的toString是：

@Override
public String toString() {
    return "Instructor [salary=" + salary + ", classList=" + classList
            + ", openTimeSlots=" + openTimeSlots + ", "
            + super.toString() + "]";
}

和super.toString（）是：

@Override
public String toString() {
    return "[idNumber=" + idNumber + ", email=" + email
            + "]";
}

我不确定原因，但是adminStaff1.assignInstructor似乎也在解决这个问题，它是：

public void enrollStudent(Student student, Class aClass){
    aClass.checkIfFilled();
    if(!aClass.getFilled()){
        aClass.addStudent(student);
        student.addClass(aClass);
        aClass.increaseEnrollment();
    } else {
        System.out.println("Could not add student because the class is currently full.");
    }
}

如果有人能帮我理解错误，我真诚地感谢。感谢。

Answer 1

当您在toString()上致电Class时，其中包含Instructor（Instructor包含Class）。这是一个循环。打破它，

return "Instructor [salary=" + salary + /* ", classList=" + classList */
        + ", openTimeSlots=" + openTimeSlots + ", "
        + super.toString() + "]";

或者，

return "Class [lectureHall=" + lectureHall + ", currentEnrollment=" 
        + currentEnrollment + ", timeSlot=" + timeSlot + ", filled=" + filled
        + ", studentList=" + studentList + "]";

toStrings（）的堆栈溢出错误（java）

1 个答案: