Java入门学习笔记（十一）——Java异常处理

矫情吗；* 2022-12-12 04:58 180阅读 0赞

# 一、Java异常处理 #

## 1.异常类TriangleException1 ##

package try_a_package;
    
    public class TriangleException1 extends Exception{
        
    	private String msg;
    	TriangleException1()
    	{
        
    		msg="存在小于或等于0的边";
    	}
    	@Override
    	public String toString()
    	{
        
    		return "异常："+msg;
    	}
    }

## 2.异常类TriangleException2 ##

package try_a_package;
    
    public class TriangleException2 extends Exception{
        
    	String msg;
    	TriangleException2()
    	{
        
    		msg="异常：三角形存在两边之和大于第三边";
    	}
    	public String toString()
    	{
        
    		return msg;
    	}
    }

## 3.测试类Triangle10\_1 ##

package try_a_package;
    
    import java.util.Scanner;
    
    public class Triangle10_1 {
        
    	private double a,b,c;
    	
    	Triangle10_1(double a,double b,double c)
    	{
        
    		this.a=a;
    		this.b=b;
    		this.c=c;
    	}
    	
    	public double getArea() throws TriangleException1,TriangleException2
    	{
        
    		TriangleException1 t1=new TriangleException1();
    		TriangleException2 t2=new TriangleException2();
    		if(a<=0 || b<=0 || c<=0)
    		{
        
    			throw t1;
    		}
    		if(a+b<=c || b+c<=a || a+c<=b)
    		{
        
    			throw t2;
    		}
    		double p,s;
    		p=(a+b+c)/2;
    		s=Math.sqrt(p*(p-a)*(p-b)*(p-c));
    		return s;
    	}
    	
    	public static void main(String[] args)
    	{
        
    		Scanner sc=new Scanner(System.in);
    		double a,b,c;
    		System.out.println("输入三边长：");
    		a=sc.nextDouble();
    		b=sc.nextDouble();
    		c=sc.nextDouble();
    		try
    		{
        
    			Triangle10_1 t1=new Triangle10_1(a,b,c);
    			System.out.println("三角形的面积是："+t1.getArea());
    		}
    		catch(TriangleException1 e1)
    		{
        
    			System.out.println(e1);
    		}
    		catch(TriangleException2 e2)
    		{
        
    			System.out.println(e2);
    		}
    		finally
    		{
        
    			// 无论是否发生异常，都会执行
    			System.out.println("求三角形面积");
    		}
    	}
    }

## 4. 运行结果 ##

![在这里插入图片描述][20201006164239928.png_pic_center]  
![在这里插入图片描述][20201006164257695.png_pic_center]  
![在这里插入图片描述][20201006164316922.png_pic_center]

[20201006164239928.png_pic_center]: /images/20221123/619f9c58c7564b148e1ae2905110462e.png
[20201006164257695.png_pic_center]: /images/20221123/b9020dd35ab341cfa48c3f1f897f8b0a.png
[20201006164316922.png_pic_center]: /images/20221123/fef038f38e554e8f995d04a061ba039f.png