异常体系结构 throwable

 1 package com.yhqtv.demo01Exception;
 2 /*
 3 * 一、异常体系结构
 4 *java.lang.Throwable
 5 *        ------java.lang.Error:一般不编写针对性的代码进行处理。
 6 *        ------java.lang.Exception:可以进行异常的处理
 7 *                  ----------编译时异常(checked)
 8 *                             -------IOException
 9 *                                 ----------FileNotFoundException
10 *                             -------ClassNotFoundException
11 *                  ----------运行时异常(unchecked)
12 *                            --------NullPointerException
13 *                            --------ArrayIndexOutOfBoundsException
14 *                            --------ClassCastException
15 *                            --------NumberFormatException
16 *                            --------InputMismatchException
17 *                            --------ArithmeticException
18 *
19 *面试题,常见的异常都有哪些?举例说明
20 * */
21 
22 import org.junit.Test;
23 
24 import java.io.File;
25 import java.io.FileInputStream;
26 import java.util.Date;
27 import java.util.Scanner;
28 
29 public class ExceptionTest {
30     //##################以下是编译时异常########################
31    @Test
32    public void test7(){
33       File file=new File("hello.txt");
34       FileInputStream fis=new FileInputStream(file);
35 
36       int data=fis.read();
37       while (data!=-1) {
38          System.out.println((char) data);
39          data =fis.read();
40 
41       }
42       fis.close();
43 
44    }
45    //##################以下是运行时异常########################
46    //ArithmeticException
47    @Test
48    public void test6(){
49       int a=10;
50       int b=0;
51       System.out.println(a/b);
52 
53    }
54    //InputMismatchException
55    @Test
56    public void test5(){
57 //      Scanner sc=new Scanner(System.in);
58 //      int nextInt = sc.nextInt();
59    }
60    //NumberFormatException
61    @Test
62    public void test4(){
63       String str="123";
64       str="abc";
65       int i = Integer.parseInt(str);
66    }
67 
68    //ClassCastException
69    @Test
70    public void test3(){
71       Object obj=new Date();
72       String str=(String)obj;
73 
74    }
75 
76    //ArrayIndexOutOfBoundsException
77    @Test
78    public void test2(){
79 //      int[] arr=new int[3];
80 //      System.out.println(arr[6]);
81 
82       String str="abc";
83       System.out.println(str.charAt(3));
84 
85    }
86 
87 
88     //NullPointerException
89    @Test
90    public void test1(){
91 //      int[] arr=null;
92 //      System.out.println(arr[3]);
93 
94       String str="abc";
95       str=null;
96       System.out.println(str.charAt(3));
97    }
98 
99 }

 

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