[英]Asking for input after catching an exception
I want the user to enter a number which is scanned by the following code: 我希望用户输入一个由以下代码扫描的数字:
scanner.nextInt();
If a user enters a string instead, the program throws InputMismatchException
, which is obvious. 如果用户输入字符串,程序会抛出InputMismatchException
,这很明显。 I want to catch the exception in such a way that the program prompts the user to enter an input until the user enters an integer value. 我想以这样的方式捕获异常,即程序提示用户输入输入,直到用户输入整数值。
Scanner scanner = new Scanner(System.in);
while(true) {
try {
System.out.println("Please enter a number: ");
int input = scanner.nextInt();
System.out.println(input);
//statements
break;
}
catch(InputMismatchException | NumberFormatException ex ) {
continue;
}
}
This code creates an infinite loop if a string is entered. 如果输入字符串,此代码将创建无限循环。
The answer to my problem is as follows: 我的问题的答案如下:
Scanner scanner = new Scanner(System.in);
while(true) {
try {
System.out.println("Please enter a number: ");
int input = scanner.nextInt();
System.out.println(input);
//statements
break;
}
catch(InputMismatchException | NumberFormatException ex ) {
scanner.next();//new piece of code which parses the wrong input and clears the //scanner for new input
continue;
}
}
Put Scanner scanner = new Scanner(System.in);
放Scanner scanner = new Scanner(System.in);
within your while
loop. 在你的while
循环中。
Scanner scanner;
while(true) {
try {
System.out.println("Please enter a number: ");
scanner = new Scanner(System.in);
int input = scanner.nextInt();
System.out.println(input);
//statements
break;
}
catch(InputMismatchException | NumberFormatException ex ) {
System.out.println("I said a number...");
}
}
How about this? 这个怎么样?
while(true) {
try {
System.out.println("Please enter a number: ");
Scanner scanner = new Scanner(System.in);
int input = scanner.nextInt();
System.out.println("\n\nEntered number is : " + input);
break;
} catch(InputMismatchException | NumberFormatException ex ) {
System.out.println("\n\nInput was not a number. Please enter number again : ");
} catch(Exception e ) {
System.out.println("\n\nException caught :: " + e);
}
}
I have also removed continue
syntax as those are not needed. 我还删除了continue
语法,因为不需要这些语法。
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