自定义异常类：三角形的判断和面积

 1 package Test;
 2 
 3 import java.util.Scanner;
 4 
 5 class NotSanjiaoException extends Exception{
 6     /**
 7      * 
 8      */
 9     private static final long serialVersionUID = 1L;
10 
11     public NotSanjiaoException(String Message,Throwable Cause) {
12         super(Message,Cause);    
13     }
14     
15     public NotSanjiaoException(String Message) {
16         super(Message);
17     }
18     
19     public NotSanjiaoException(Throwable cause) {
20         super(cause);
21     }
22 } 
23 
24 class Sanj{
25      double x;
26      double y;
27      double z;
28     public Sanj(double a,double b,double c) throws NotSanjiaoException {
29         x=a;
30         y=b;
31         z=c;
32         try {
33             if((x>=y+z)||(x<=Math.abs(y-z))||(y>=x+z)||(y<=Math.abs(x-z))||(z>=y+x)||(z<=Math.abs(y-x))||(x==0)||(y==0)||(z==0))34             throw new Exception("这三个三角形不能构成三角形");
35             
36         }
37         catch(Exception e){
38             System.err.println("Exception handled in the method NotSanjiaoException");
39             throw new  NotSanjiaoException("出现异常",e);
40             
41         }
42     }
43     
44     public double getArea() {
45         double p;
46         p=(x+y+z)/2.0;
47         double s=p*(p-x)*(p-y)*(p-z);
48         s=Math.sqrt(s);
49         return  s;
50         
51     }
52     
53     public void showInfo() {
54         System.out.println("第一条边的长度："+x+"第二条边的长度"+y+"第三条边的长度"+z);
55     }
56 }
57 public class Test {
58             public static void main(String[] args) {
59                 double a1,a2,a3;
60                 System.out.println("请依次输入三角形边的长度：");
61                 Scanner sc =new Scanner(System.in);
62                 a1=sc.nextDouble();
63                 a2=sc.nextDouble();
64                 a3=sc.nextDouble();
65                 sc.close();
66                 try {
67                     Sanj s = new Sanj(a1,a2,a3);
68                     double x = s.getArea();
69                     System.out.println("三角形的面积为:"+x);
70                     s.showInfo();
71                 }
72                 catch(Exception e ) {
73                     System.err.println("对不起，您输入的边长："+a1+"  "+a2+"  "+a3+"不能构成三角形");
74                     
75                     
76                 }
77                 
78             }
79 }