重写Java中未经检查的异常类中的方法
我试图重写Java中NumberFormatException类中的getMessage()方法,这是一个未经检查的异常。由于某种原因,我无法覆盖它。我知道这一定很简单,但我不明白我可能会错过什么。有人能帮忙吗?这是我的密码:重写Java中未经检查的异常类中的方法,java,methods,numberformatexception,overriding,unchecked-exception,Java,Methods,Numberformatexception,Overriding,Unchecked Exception,我试图重写Java中NumberFormatException类中的getMessage()方法,这是一个未经检查的异常。由于某种原因,我无法覆盖它。我知道这一定很简单,但我不明白我可能会错过什么。有人能帮忙吗?这是我的密码: public class NumberFormatSample extends Throwable{ private static void getNumbers(Scanner sc) { System.out.println("Enter any two i
public class NumberFormatSample extends Throwable{
private static void getNumbers(Scanner sc) {
System.out.println("Enter any two integers between 0-9 : ");
int a = sc.nextInt();
int b = sc.nextInt();
if(a < 0 || a > 9 || b < 0 || b > 9)
throw new NumberFormatException();
}
@Override
public String getMessage() {
return "One of the input numbers was not within the specified range!";
}
public static void main(String[] args) {
try {
getNumbers(new Scanner(System.in));
}
catch(NumberFormatException ex) {
ex.getMessage();
}
}
public class NumberFormatSample扩展可丢弃{
专用静态无效GetNumber(扫描仪sc){
System.out.println(“输入0-9之间的任意两个整数:”);
int a=sc.nextInt();
int b=sc.nextInt();
如果(a<0 | a>9 | b<0 | b>9)
抛出新的NumberFormatException();
}
@凌驾
公共字符串getMessage(){
return“其中一个输入数字不在指定范围内!”;
}
公共静态void main(字符串[]args){
试一试{
GetNumber(新扫描仪(System.in));
}
捕获(NumberFormatException ex){
例如getMessage();
}
}
}编辑(在您的评论之后)
似乎您正在寻找:
public class NumberFormatSample {
private static void getNumbers(Scanner sc) {
System.out.println("Enter any two integers between 0-9 : ");
int a = sc.nextInt();
int b = sc.nextInt();
if(a < 0 || a > 9 || b < 0 || b > 9)
throw new NumberFormatException("One of the input numbers was not within the specified range!");
}
public static void main(String[] args) {
try {
getNumbers(new Scanner(System.in));
}
catch(NumberFormatException ex) {
System.err.println(ex.getMessage());
}
}
}
公共类编号格式示例{
专用静态无效GetNumber(扫描仪sc){
System.out.println(“输入0-9之间的任意两个整数:”);
int a=sc.nextInt();
int b=sc.nextInt();
如果(a<0 | a>9 | b<0 | b>9)
抛出新的NumberFormatException(“其中一个输入数字不在指定范围内!”);
}
公共静态void main(字符串[]args){
试一试{
GetNumber(新扫描仪(System.in));
}
捕获(NumberFormatException ex){
System.err.println(例如getMessage());
}
}
}
编辑(在您的评论之后)
似乎您正在寻找:
public class NumberFormatSample {
private static void getNumbers(Scanner sc) {
System.out.println("Enter any two integers between 0-9 : ");
int a = sc.nextInt();
int b = sc.nextInt();
if(a < 0 || a > 9 || b < 0 || b > 9)
throw new NumberFormatException("One of the input numbers was not within the specified range!");
}
public static void main(String[] args) {
try {
getNumbers(new Scanner(System.in));
}
catch(NumberFormatException ex) {
System.err.println(ex.getMessage());
}
}
}
公共类编号格式示例{
专用静态无效GetNumber(扫描仪sc){
System.out.println(“输入0-9之间的任意两个整数:”);
int a=sc.nextInt();
int b=sc.nextInt();
如果(a<0 | a>9 | b<0 | b>9)
抛出新的NumberFormatException(“其中一个输入数字不在指定范围内!”);
}
公共静态void main(字符串[]args){
试一试{
GetNumber(新扫描仪(System.in));
}
捕获(NumberFormatException ex){
System.err.println(例如getMessage());
}
}
}
您不需要重写任何内容或创建可丢弃的的任何子类
只需调用抛出新的NumberFormatException(message)
您不需要重写任何内容或创建任何Throwable
的子类
只需调用抛出新的NumberFormatException(message)
,正如其他答案所指出的,您实际尝试的操作根本不需要覆盖
但是,如果确实需要重写NumberFormatException
中的方法,则必须:
扩展该类,而不是可丢弃的
,以及
- 实例化类的实例,而不是
NumberFormatException
例如:
// (Note: this is not a solution - it is an illustration!)
public class MyNumberFormatException extends NumberFormatException {
private static void getNumbers(Scanner sc) {
...
// Note: instantiate "my" class, not the standard one. If you new
// the standard one, you will get the standard 'getMessage()' behaviour.
throw new MyNumberFormatException();
}
@Override
public String getMessage() {
return "One of the input numbers was not within the specified range!";
}
public static void main(String[] args) {
try {
getNumbers(new Scanner(System.in));
}
// Note: we can still catch NumberFormatException, because our
// custom exception is a subclass of NumberFormatException.
catch (NumberFormatException ex) {
ex.getMessage();
}
}
}
通过更改现有类重写不起作用。它的工作原理是在现有类的基础上创建一个新类。。。并使用新类。正如其他答案所指出的,您实际尝试执行的操作根本不需要重写
但是,如果确实需要重写NumberFormatException
中的方法,则必须:
扩展该类,而不是可丢弃的
,以及
- 实例化类的实例,而不是
NumberFormatException
例如:
// (Note: this is not a solution - it is an illustration!)
public class MyNumberFormatException extends NumberFormatException {
private static void getNumbers(Scanner sc) {
...
// Note: instantiate "my" class, not the standard one. If you new
// the standard one, you will get the standard 'getMessage()' behaviour.
throw new MyNumberFormatException();
}
@Override
public String getMessage() {
return "One of the input numbers was not within the specified range!";
}
public static void main(String[] args) {
try {
getNumbers(new Scanner(System.in));
}
// Note: we can still catch NumberFormatException, because our
// custom exception is a subclass of NumberFormatException.
catch (NumberFormatException ex) {
ex.getMessage();
}
}
}
通过更改现有类重写不起作用。它的工作原理是在现有类的基础上创建一个新类。。。使用新类。实际上,规范提到我应该只抛出NumberFormatException对象。是的,我刚刚得到了。我正在编辑原始帖子,但你已经先编辑了你的。事实上,说明书提到我应该只抛出NumberFormatException对象。是的,我刚刚得到了。我正在编辑原始帖子,但你已经先编辑了你的。谢谢你的精彩解释。谢谢你的精彩解释。