Java异常

1. try{ }catch（）{ }
2. finally语句块无论是否异常都会进行
3. 多重catch
4. try catch嵌套
5. 自定义异常：

自定义异常类

public class ExceptionWork1 extends Exception{
    public ExceptionWork1(){

    }
    public ExceptionWork1(String arg){
        super(arg);
    }
}

定义

public class SanJ {
   static double x,y,z;
   public SanJ(double a,double b,double c){
       x=a;
       y=b;
       z=c;
   }
   public void getarea(){
       System.out.println(x);
       System.out.println(y);
       System.out.println(z);
   }
   public void showInfo(){
       System.out.println("面积");
   }
   public void ec()throws ExceptionWork1{
       if(x+y>z&&x+z>y&&y+z>x){
       }else {
           throw new ExceptionWork1("不能构成三角形");
       }
   }
}

//实现

public class TeseSanJ {
    public static void main(String[] args) {
        SanJ sanJ=new SanJ(1,2,3);
        try {
            sanJ.ec();
            sanJ.showInfo();
            sanJ.getarea();
        }catch (ExceptionWork1 e){
            e.printStackTrace();
        }
    }
}