Question

我有3个java程序

第一名：

public class Person{
    private String firstname;
    private String lastname;
    private int g1;
    private int g2;
    private int g3;
    private int periodic;



    public Person(String firstname,String lastname,int periodic,int g1,int g2,int g3){
        this.firstname = firstname;
        this.lastname = lastname;
        this.periodic=periodic;
        this.g1=g1;
        this.g2=g2;
        this.g3=g3;
    }

    public void print(){

        int a=(g1+g2+g3)/3;
        System.out.println("\t"+ firstname + " "+ lastname);
        System.out.println("Periodic Exam: " + periodic);
        System.out.println("Grade of quiz 1: "+g1);
        System.out.println("Grade of quiz 2: "+g2);
        System.out.println("Grade of quiz 3: "+g3);
        System.out.println("Average of the quizzes: "+a);
    }


}

第二个：

public class Student extends Person{  //inherits Person//

    public Student(String firstname,String lastname,int periodic,int g1,int g2,int g3){
        super(firstname,lastname,periodic,g1,g2,g3);    
    }

    public void print(){
        System.out.println("Student Details:");
        super.print();

    }
}

第三个：

public class Main{
    public static void main(String[] args){

        Person persons[] = new Person[3];
        persons[0] = new Student("Robert","Almazan",91,90,85,86);
        persons[1] = new Student("Dennis","Navan",92,89,84,87);
        persons[2] = new Student("Allan","Villariza",93,79,81,84);

        for(Person person:persons){
            person.print();

        }
}

当我改变像这样的人时，我想做的就是捕捉异常

Person persons[] = new Person[3];
        persons[0] = new Student("Robert","Almazan","ZZ",0,-85,86);
        persons[1] = new Student("Dennis","Navan","ASA",0,-84,87);
        persons[2] = new Student("Allan","Villariza","sa",0,-81,84);

我试过这样做

public class Main{
    public static void main(String[] args){


    try{

        Person persons[] = new Person[3];
        persons[0] = new Student("Robert","Almazan","ZZ",90,85,86);
        persons[1] = new Student("Dennis","Navan","ASA",89,84,87);
        persons[2] = new Student("Allan","Villariza","9",79,81,84);

        for(Person person:persons){
            person.print();



        }
    }//try
    catch(ArithmeticException e){

        System.out.println("Arithmetic Error");
    }

    catch(InputMismatchException e){

        System.out.println("Input Error");
    }
    finally{

        System.out.println("Thank you");
    }


    }//main
}

程序没有捕获异常

当我编译时，它仍然说像String这样的错误不能转换为int，它总是接受负数并且它不会捕获异常

需要帮助......

Answer 1

您的代码：

persons[0] = new Student("Robert","Almazan","ZZ",0,-85,86); 
                                            ^^^^

是编译时错误，因为您接受的第三个参数是int类型

public Student(String firstname,String lastname,int periodic,int g1,int g2,int g3){
                                                ^^^^^^^^^^^

您只能在运行时和时捕获异常，而不是在编译时。

Answer 2

当我编译时，它仍然说像String这样的错误无法转换为 int，它总是接受负数而且它不会捕获异常

首先异常发生在运行时而不是编译时，因为您的程序有编译时错误，这是非常自我解释的，即String cannot be converted into int。

问题是

new Student("Robert","Almazan","ZZ",0,-85,86);
                                /\
                                ||
                              This is String not an int

但是你的学生类构造函数就像这样

public Student(String firstname,String lastname,int periodic,int g1,int g2,int g3)
                                                      /\
                                                      ||
                                                    int not String

这就是为什么编译时错误即将来临，现在你的程序甚至没有成功编译，所以没有机会Exception直到你的程序运行。

新手在这里，不知道在哪里使用try和catch块

2 个答案: