【宋红康学习日记20】

 1     //常见运行时异常
 2     //01 数组越界异常
 3         @Test
 4         public void test1(){
 5             try{
 6             int[] arr=new int[5];
 7             System.out.println(arr[5]);
 8             }catch(Exception e){
 9                 e.printStackTrace();
10                 System.out.println(e.getMessage());
11             }finally{
12                 System.out.println("你真帅");
13             }
14         }
15     //02 算术异常
16         @Test
17         public void test2(){
18             try {
19                 int i=90;
20                 System.out.println(i/0);
21             } catch (Exception e) {
22                 // TODO Auto-generated catch block
23                 e.printStackTrace();
24             }
25         }
26         //03 类型转换异常
27         @Test
28         public void test3(){
29             try {
30                 Object obj=new Date();
31                 String str=(String)obj;
32             } catch (Exception e) {
33                 e.printStackTrace();
34             }
35         }
36         //04 空指针异常
37         @Test
38         public void test4(){
39             try {
40                 String str="SSSS";
41                 str=null;
42                 System.out.println(str.toString());
43             }catch (Exception e) {
44                 e.printStackTrace();
45             }
46         }

 1     //编译时异常
 2         @Test
 3         public void test5(){
 4             FileInputStream fis=null;
 5             try{
 6                 fis=new FileInputStream(new File("hello.txt"));
 7                 int b=0;
 8                 while((b=fis.read())!=-1){
 9                     System.out.println((char)b);
10                 }
11             }catch(FileNotFoundException e){
12                 e.printStackTrace();
13             }catch(IOException e){
14                 e.printStackTrace();
15             }finally{
16                 try {
17                     fis.close();
18                 } catch (IOException e) {
19                     // TODO Auto-generated catch block
20                     e.printStackTrace();
21                 }
22             }
23         }

 1 //06 自定义抛出的 异常类
 2 public class MyException extends RuntimeException{
 3     static final long serialVersionUID = -703489745766939L;
 4     public MyException(){
 5         
 6     }
 7     public MyException(String msg){
 8         super(msg);
 9     }
10 }

 1 class AAA{
 2     public void method11() throws Exception{
 3         
 4     }
 5     
 6 }
 7 //重写
 8 class BBB extends AAA{
 9 public void method11() throws IOException{
10         
11     }
12 }