我已经为MonthsNumberException编写了代码，这个代码写得正确吗？我在异常方面遇到了很大的问题，我该如何为MonthsNameException创建异常，以便当用户在不在列表中的月份键入时，会引发异常。
public class Month {
private int monthNumber;
/**
* Creates a new month set to January
*/
public Month(){
monthNumber = 1;
}
/**
* Creates a month set to the month number provided by the user
* @param m the number of the month
*/
public Month(int m) throws MonthsNumberException{
if (m<1 || m>12){
throw new MonthsNumberException("Number has to be greater than 1 and less than 12");
}else{
monthNumber = m;
}
}
/**
* Creates a month based on the string name provided
* @param m String values for the name of the month
*/
public Month(String m) throws MonthsNameException{
switch(m){
case "January":
monthNumber = 1;
break;
case "February":
monthNumber = 2;
break;
case "March":
monthNumber = 3;
break;
case "April":
monthNumber = 4;
break;
case "May":
monthNumber = 5;
break;
case "June":
monthNumber = 6;
break;
case "July":
monthNumber = 7;
break;
case "August":
monthNumber = 8;
break;
case "September":
monthNumber = 9;
break;
case "October":
monthNumber = 10;
break;
case "November":
monthNumber = 11;
break;
case "December":
monthNumber = 12;
break;
}
}
/**
* changes the month to the number provided
* @param m the number of the month
*/
public void setMonthNumber(int m) throws MonthsNumberException{
if (m<1 || m>12){
throw new MonthsNumberException("Number has to be greater than 1 and less than 12");
}else{
monthNumber = m;
}
}
/**
* returns the number of the month
* @return the number of the month
*/
public int getMonthNumber(){
return monthNumber;
}
/**
* returns the name of the month
* @return the name of the month
*/
public String getMonthName(){
String month="";
switch(monthNumber){
case 1:
month = "January";
break;
case 2:
month = "February";
break;
case 3:
month = "March";
break;
case 4:
month = "April";
break;
case 5:
month = "May";
break;
case 6:
month = "June";
break;
case 7:
month = "July";
break;
case 8:
month = "August";
break;
case 9:
month = "September";
break;
case 10:
month = "October";
break;
case 11:
month = "November";
break;
case 12:
month = "December";
break;
}
return month;
}
/**
* returns a string representation of the month
* @return the name of the month
*/
public String toString(){
return getMonthName();
}
/**
* if the two items are the same returns true
* @param m the month object to compare
* @return true if they are the same, false if not
*/
public boolean equals(Month m){
if (m.getMonthNumber() == this.getMonthNumber()){
return true;
}else{
return false;
}
}
/**
* If this calling item is after the month object passed as argument returns true
* @param m the month object
* @return true if calling object greater, false of argument greater
*/
public boolean greaterThan(Month m){
if (this.getMonthNumber()>m.getMonthNumber()){
return true;
}else{
return false;
}
}
/**
* If this calling item is before the month object passed as argument returns true
* @param m the month object
* @return true if calling object less than, false of argument less than
*/
public boolean lessThan(Month m){
if (this.getMonthNumber()<m.getMonthNumber()){
return true;
}else{
return false;
}
}
class MonthsNumberException extends Exception
{
public MonthsNumberException(String message)
{
super(message);
}
}
class MonthsNameException extends Exception
{
public MonthsNameException(String message)
{
super(message);
}
}
}
case "December":
monthNumber = 12;
break;
default:
throw new MonthsNameException("Invalid month name: " + m);
请注意，有一个标准的运行时异常：IllegalArgumentException。您应该使用它，而不是定义自定义的、已检查的异常。
此外，返回布尔值的方法应该简化为
return m.getMonthNumber() == this.getMonthNumber();