常见异常

异常体系结构

java.lang.Throwable
|-----java.lang.Error:一般不编写针对性的代码进行处理
|-----java.lang.Exception:可以进行异常的处理
|------编译时异常(checked)
|-----IOException
|-----FileNotFoundException
|-----ClassNotFoundException
|------运行时异常(unchecked,RuntimeException)
|-----NullPointerException
|-----ArrayIndexOutOfBoundsException
|-----ClassCastException
|-----NumberFormatException
|-----InputMismatchException
|-----ArithmeticException

package com.atguigu.java1;import java.io.File;
import java.io.FileInputStream;
import java.util.Date;
import java.util.Scanner;import org.junit.Test;public class ExceptionTest {//******************以下是编译时异常***************************@Testpublic void test7(){
//		File file = new File("hello.txt");
//		FileInputStream fis = new FileInputStream(file);
//		
//		int data = fis.read();
//		while(data != -1){
//			System.out.print((char)data);
//			data = fis.read();
//		}
//		
//		fis.close();}//******************以下是运行时异常***************************//ArithmeticException@Testpublic void test6(){int a = 10;int b = 0;System.out.println(a / b);}//InputMismatchException@Testpublic void test5(){Scanner scanner = new Scanner(System.in);int score = scanner.nextInt();System.out.println(score);scanner.close();}//NumberFormatException@Testpublic void test4(){String str = "123";str = "abc";int num = Integer.parseInt(str);}//ClassCastException@Testpublic void test3(){Object obj = new Date();String str = (String)obj;}//IndexOutOfBoundsException@Testpublic void test2(){//ArrayIndexOutOfBoundsException
//		int[] arr = new int[10];
//		System.out.println(arr[10]);//StringIndexOutOfBoundsExceptionString str = "abc";System.out.println(str.charAt(3));}//NullPointerException@Testpublic void test1(){//		int[] arr = null;
//		System.out.println(arr[3]);String str = "abc";str = null;System.out.println(str.charAt(0));}}