一篇文章看懂Java异常处理

package org.oracle.test;

public class TryDemo9 {
    public static void main(String[] args) {
    	        System.out.println(1/0);//0不能做除数
    	  
    	        System.out.println("你好");//程序捕获异常，程序终止，不执行
    }
}

package org.oracle.test;
import java.util.Scanner;
public class TryDemo2 {
	public static void main(String[] args) {
		System.out.println(testOne());
	}	
	/*
	 *  当try、catch、finally代码块中都有return语句，
	 *  程序无论报错与否都会执行finally里面的renturn语句
	 */
	public static double testOne() {
		try {
			Scanner sc = new Scanner(System.in);
			System.out.println("请输入第一个数字：");
			int a = sc.nextInt();
			System.out.println("请输入第二个数字：");
			int b = sc.nextInt();
			int result = a / b;
//			System.out.println("result：" + result);
			System.out.println("执行了try块");
			return result;		
		}catch (Exception e) {
			e.printStackTrace();
			return 0;
		}finally {
			return -1000;
		}
	}
}

package org.oracle.test;

import java.util.InputMismatchException;

public class TryDemo8 {
	public static void main(String[] args) {
		try {
			testThree();
		} catch (Exception e) {
			System.out.println(e.getMessage());
			e.printStackTrace();
		}
	}
	public static void testOne() throws InputMismatchException{
		throw new InputMismatchException();
	}
	public static void testTwo() throws Exception {
		try {
			testOne();
		} catch (InputMismatchException e) {
			throw new Exception("新异常1",e);
		}
	}

	public static void testThree() throws Exception {
		try {
			testTwo();
		} catch (Exception e) {
			Exception e1 = new Exception("新异常2");
			e1.initCause(e);
			throw e1;
		}
	}
}

package org.oracle.test;

import java.util.Scanner;

public class TryDemo6 {

	public static void main(String[] args){
		try {
			hotelRule();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	/*
	 * 	基帝开了个情侣酒店，基帝酒店规矩：18岁以下和80岁上以上客户，需要家人陪同入住
	 */
	public static void hotelRule() throws Exception {
		Scanner sc = new Scanner(System.in);
		System.out.println("请输入客户年龄：");
		int age = sc.nextInt();
		if(age < 18 || age > 80) {
			throw new HotelException();
		}else {
			System.out.println("成功入住");
		}
	}

}

package org.oracle.test;
/*
 * 自定义异常需继承Exception
 */
public class HotelException extends Exception{

	public HotelException() {
		super("由于年龄问题，无法入住");
	}
	
}