为什么在try外面声明Scanner对象，只能在try中使用一次，第二次就不能用了，try在一个死循环中

Question

public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int age;
                //这里是为了判断他输入的是否为int数值
                //不是的话报错提示进入下一次输入
        for (;;){
            System.out.println("请输入年龄：");
            try {
                //Scanner放外面内部访问不到
                //第一次进来正常使用
                //循环第二次进来就没有输入操作了
                age = sc.nextInt();
            }catch (Exception e){
                e.printStackTrace();
                continue;
            }
            break;
        }

//一次错误的输入之后就会循环报错，循环没有问题 但是再没有输入操作了

请输入年龄：
asf
java.util.InputMismatchException
    at java.base/java.util.Scanner.throwFor(Scanner.java:939)
    at java.base/java.util.Scanner.next(Scanner.java:1594)
    at java.base/java.util.Scanner.nextInt(Scanner.java:2258)
    at java.base/java.util.Scanner.nextInt(Scanner.java:2212)
    at com.work.EX.main(EX.java:13)
请输入年龄：
java.util.InputMismatchException
    at java.base/java.util.Scanner.throwFor(Scanner.java:939)
    at java.base/java.util.Scanner.next(Scanner.java:1594)
    at java.base/java.util.Scanner.nextInt(Scanner.java:2258)
    at java.base/java.util.Scanner.nextInt(Scanner.java:2212)
    at com.work.EX.main(EX.java:13)
请输入年龄：
java.util.InputMismatchException
    at java.base/java.util.Scanner.throwFor(Scanner.java:939)
    at java.base/java.util.Scanner.next(Scanner.java:1594)
    at java.base/java.util.Scanner.nextInt(Scanner.java:2258)
    at java.base/java.util.Scanner.nextInt(Scanner.java:2212)
    at com.work.EX.main(EX.java:13)
请输入年龄：
java.util.InputMismatchException
    at java.base/java.util.Scanner.throwFor(Scanner.java:939)
    at java.base/java.util.Scanner.next(Scanner.java:1594)
    at java.base/java.util.Scanner.nextInt(Scanner.java:2258)
    at java.base/java.util.Scanner.nextInt(Scanner.java:2212)
    at com.work.EX.main(EX.java:13)

Answer 1

把Scanner sc = new Scanner(System.in);放进for循环里