Java의 예외 개요

public class text3 {
    public static void main(String[] args) {
		System.out.println("main开始执行");
		text3 a=new text3();
		a.text();
		System.out.println("main执行结束");
	}
    public void text() {
    	int a;
    	//try {
    		 a=2/0;
    		System.out.println(a);
    	//}catch(ArithmeticException e){
    		//System.out.println("程序发生了异常");
    	//}
    }
}

public void text1() throws ArithmeticException{
		
	}
	
	public static void main(String[] args) {
		Text t=new Text();
		try {
			t.text();
		} catch (Exception e) {
			// TODO Auto-generated catch block
			System.out.println(e.getMessage());
		}
	}
	public void text() throws Exception {
		//手动抛出异常
		throw new Exception("这是手动抛出来的");
	}
}

public class Textthrow {
     
public static void main(String[] args) {
	double a=Math.random();
    try {
   	 if(a>0.5) {
   		 System.out.println(a+"程序不报错");
   	 }
   	 else {
   		 throw new Exception();
   	 }
    }catch(Exception e) {
   	 System.out.println("这是外层捕获的对象"+e);
   	 try {
   		 a=1/0;
   	 }catch(ArithmeticException e1) {
   		 System.out.println("这是内层捕获的对象"+e1);
   		 
   	 }finally {
   		 System.out.println("这是内层的finally块");
   	 }
    }finally {
   	 System.out.println("这是外层的finally块 ");
    }
}
}

public class ExceptionChainText {
      public static void main(String[] args) {
		Calculator c=new Calculator();
		try {
			c.chufa(1, 0);
		}catch(NumberCalculateExcetption e) {
			e.printStackTrace();
			System.out.println("错误原因"+e);
		}
	}
}
class Calculator{
	public int chufa(int i,int j) throws NumberCalculateExcetption {
		if(j==0) {
			NumberCalculateExcetption e = new
					NumberCalculateExcetption ("计算错误");
			NegativeNumberException e1=	new
					NegativeNumberException("除数不能为0");
		 e.initCause(e1);//由e1引起的异常
		 throw e;
		}
		return 0;
	}
}
class NegativeNumberException extends Exception{
	public NegativeNumberException(String msg) {
		super(msg);
	}
}
class NumberCalculateExcetption extends Exception{
	public NumberCalculateExcetption(String msg) {
		super(msg);
	}
}