封装更新

import static org.junit.Assert.*;

import org.junit.Test;


public class FZTest {

    int z;
    @Test
    public void testJia() {
        FZ fz = new FZ();
        z = fz.jia(3, 1);
        assertEquals(4,z);
    }
    @Test(expected=ArithmeticException.class)
    public void testchu() {
        double b;
        FZ fz = new FZ();
        b = fz.Chu(3, 0);
        
    }
    @Test
    public void testjian() {
        
        FZ fz = new FZ();
        z = fz.jian(3, 0);
        assertEquals(3,z);
        
    }
    @Test
    public void testCheng() {
        
        FZ fz = new FZ();
        z = fz.Cheng(3, 0);
        assertEquals(0,z);
        
    }


}

抛出异常后

import java.util.Random;


public class FZ {
    private int a;
    private int b;
    int c;
    public int  jia(int a,int b)
    {
    
        System.out.println(""+a);
        System.out.println(""+b);
        c = a+b;
        System.out.println("a+"+"b"+"="+(a+b+"\n"));
        return c;
        
    }
    public int  jian(int a,int b)
    {
        
        System.out.println(""+a);
        System.out.println(""+b);
        c=a-b;
        System.out.println("a-"+"b"+"="+(a-b)+"\n");
        return c;
        
        
    }
    public int Cheng(int a,int b)
    {   
        System.out.println(""+a);
        System.out.println(""+b);
        c=a*b;
        System.out.println("a*"+"b"+"="+(a*b)+"\n");
        return c;
    }
    public double  Chu(int a,int b)
    {
        double c;
        c=(double) (Math.round((a/b)*100/100.0));
        System.out.println(""+a);
        System.out.println(""+b);
        if(b!=0)
            System.out.println("c=a/b="+(c)+"\n");
        else
            throw new ArithmeticException();
            System.out.println("分母不能为0！");
              
            return c;
    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
         FZ Jia=new FZ();
         Jia.jia(5, 3);
         FZ Jian=new FZ();
         Jian.jian(6,2);
         FZ cheng=new FZ();
         cheng.Cheng(6,5);
         FZ chu=new FZ();
         chu.Chu(3,0);
         
    }

}