Java学习（异常类练习题）

package com.oracle.Demo01;

public class Demo02 {
 // 写一个计算圆的面积的方法，传一个半径，返回面积
    public static void main(String[] args) {
        double s=0;
        s = area(-4);
        System.out.println(s);
}
    public static double area(double r){
        try {
            if(r<=0){
                throw new RuntimeException();  //RuntimeException  运行异常，不会声明，不会处理异常，直接报错并且停止
            }
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        double s=Math.PI*r*r;
        return s;
    }
}

package com.oracle.Demo01;

import java.util.Scanner;

public class Demo03 {
    //现在要创建一个检测负数的异常类，如果是正数，则抛出异常
    public static void main(String[] args){
        /*double s=0;
        s = area(9);
        System.out.println(s);*/
        //输入任意参数，求平均数
        double s=avg(1,9,6,5,2);
        System.out.println(s);
    }
    public static double area(double r){
        if(r<=0){
            throw new FuShuException("你传了一个负数");  //报异常并传递自定义的字符串
        }
        double s=Math.PI*r*r;
        return s;
    }
    //求平均数的方法
    public static double avg(double...arr){
        double sum=0;
        for(double i:arr){
            if(i<0){
                throw new FuShuException("参数为负数");
            }
            sum=sum+i;
        }
        return sum/arr.length;
    }
}

package com.oracle.Demo01;
//自定义类异常，继承自运行异常
public class FuShuException extends RuntimeException {
    FuShuException(String mes){
        super(mes);
    }
}

package com.oracle.Demo01;

public class Demo04 {
    public static void main(String[] args) throws NoAgesException {
        method("阿易",110);
    }
    public static void method(String name,int age) throws NoAgesException{
        Person p=new Person(name,age);
        if(p.getAge()<0||p.getAge()>200){
            throw new NoAgesException("年龄数值非法");
        }
        System.out.println(p.getName()+"..."+p.getAge());
    }
}

package com.oracle.Demo01;

public class Person {
    private String name;
    private int age;
    Person(){
        
    }
    Person(String name,int age){
        this.name=name;
        this.age=age;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    
}

package com.oracle.Demo01;

public class  NoAgesException extends Exception {
    NoAgesException(){    //声明父类的异常方法
        super();
    }
    NoAgesException(String mes){
        super(mes);
    }
    
}