toString方法返回不正确的

Question

我正在学习java，我们的一个编程任务是创建一个名为month的类，这个类占用一个月的字符串并转换为其对应的int并获取月份数的int并将其转换为字符串或相应的名称。它还比较一个大于或小于另一个的月份数，这个类必须包含一个复制构造函数以及使用构造函数链接。

我的课程编译时没有错误，但问题是当我尝试在我的演示类中运行它时，它只会打印出每个println的May。

我认为问题在于toString，好像我添加了println来打印出打印出正确月份或月份数字的其他方法。下面是我的代码，我试图从学校的一位实验室助理那里得到一些帮助，但他们无法弄清楚问题是什么。提前谢谢!!

public class Month1
{
private static int monthNumber;

public Month1 ()
{
    this(1);
}

public Month1(Month1 copy)
{
    this(copy.monthNumber);
}

public Month1 (int n)
{

    if (n > 12 || n < 1)
        monthNumber = 1;
    else monthNumber = n;


}
public Month1 (String monthName)
{
    this(nameToNumber(monthName));

    if (monthName.equals("January"))
        monthNumber = 1;
     else if (monthName.equals("February"))
        monthNumber = 2;
     else if (monthName.equals("March"))
        monthNumber = 3;
     else if (monthName.equals("April"))
        monthNumber = 4;
     else if (monthName.equals("May"))
        monthNumber = 5;
     else if (monthName.equals("June"))
        monthNumber = 6;
     else if (monthName.equals("July"))
        monthNumber = 7;
     else if (monthName.equals("August"))
        monthNumber = 8;
     else if (monthName.equals("September"))
        monthNumber = 9;
     else if (monthName.equals("October"))
        monthNumber = 10;
     else if (monthName.equals("November"))
        monthNumber = 11;
     else monthNumber = 12;
 }

 public static int nameToNumber(String monthName)
 {
        if (monthName.equals("January"))
        monthNumber = 1;
     else if (monthName.equals("February"))
        monthNumber = 2;
     else if (monthName.equals("March"))
        monthNumber = 3;
     else if (monthName.equals("April"))
        monthNumber = 4;
     else if (monthName.equals("May"))
        monthNumber = 5;
     else if (monthName.equals("June"))
        monthNumber = 6;
     else if (monthName.equals("July"))
        monthNumber = 7;
     else if (monthName.equals("August"))
        monthNumber = 8;
     else if (monthName.equals("September"))
        monthNumber = 9;
     else if (monthName.equals("October"))
        monthNumber = 10;
     else if (monthName.equals("November"))
        monthNumber = 11;
     else monthNumber = 12;

     return monthNumber;
 }
 public void setMonthNumber (int n)
 {
     if (n > 12 || n < 1)
        monthNumber = 1;
     else monthNumber = n;
 }
 public int getMonthNumber ()
 {
     return monthNumber;
 }
 public String getMonthName (int n)
 {
     String monthName = "";
     if (n == 1)
        monthName = "January";
     else if (n == 2)
        monthName = "February";
     else if (n == 3)
        monthName = "March";
     else if (n == 4)
        monthName = "April";
     else if (n == 5)
        monthName = "May";
     else if (n == 6)
        monthName = "June";
     else if (n == 7)
        monthName = "July";
     else if (n == 8)
        monthName = "August";
     else if (n == 9)
        monthName = "Septemeber";
     else if (n == 10)
        monthName = "October";
     else if (n == 11)
        monthName = "November";
     else monthName = "December";

     return monthName;
 }
 public String toString ()
 {
     return getMonthName(monthNumber);
 }
 public boolean equals (Month1 m)
 {
     boolean result = false;
     if (monthNumber == m.monthNumber)
        result = true;
     else result = false;
     return result;
 }
public boolean greaterThan(Month1 m1)
{
    if(monthNumber > m1.monthNumber)
        return true;
    else
        return false;
}


public boolean lessThan(Month1 m1)
{
    if(monthNumber < m1.monthNumber)
        return true;
    else
        return false;
}
}
import java.util.*;
public class MonthDemo
{
public static void main (String [] args)
{
    Month1 month1 = new Month1(10);
    Month1 month2 = new Month1("May");

    System.out.println (month1);
    System.out.println (month2);
    // Test for equality.
    if (month1.equals(month2))
        System.out.println(month1 + " and " + month2 + " are the same month.");
    else
        System.out.println(month1 + " and " + month2 + " are NOT equal.");

    // Is m1 greater than m2?
    if (month1.greaterThan(month2))
        System.out.println(month1 + " is greater than " + month2);
    else
        System.out.println(month1 + " is NOT greater than " + month2);

    // Is m1 less than m2?
    if (month1.lessThan(month2))
        System.out.println(month1 + " is less than " + month2);
    else
        System.out.println(month1 + " is NOT less than " + month2);

    // Use copy constructor
    Month1 month3 = new Month1(month2);
    // Test for equality.
    if(month3.equals(month2))
        System.out.println(month3 + " and " + month2 + " are the same month.");
    else
        System.out.println(month3 + " and " + month2 + " are NOT equal.");
}

}