Android (Java) Study Note 84: Custom exception classes

Custom Exceptions:

Exam results must be between 0-100 obviously there is no corresponding exception in Java, we need to do an exception

Custom exceptions

Inherit from exception

Inherit from RuntimeException

Here is a code example:

 Packagecn.itcast_08;/** Java is unlikely to be considered in all cases, so in real development we may need to define our own exceptions. * and our own arbitrary write a class, is not as an exception class, to think your class is an exception class, you must inherit from exception or RuntimeException * Two ways: * A: Inherit exception * B: Inherit RuntimeException*/ Public classMyExceptionextendsException {Public myexception () {} public myexception (String message) {//Custom exception here if we do not know how to use the constructor method to assign a value, we follow the parent class (class) source code to see what people are doing with it. Super (message); }}//Public class MyException extends RuntimeException {//// }

1  Packagecn.itcast_08;2 3  Public classTeacher {4      Public voidCheckintScore)throwsMyException {5         if(Score > | | Score < 0) {6             Throw NewMyException ("score must be between 0-100");7}Else {8System.out.println ("Score No Problem");9         }Ten     } One  A     //inherit from RuntimeException for MyException -     //Public void Check (int score) { -     //if (Score > | | Score < 0) { the     //throw new MyException (); -     //} else { -     //System.out.println ("Score No Problem"); -     // } +     // } -}

1  Packagecn.itcast_08;2 3 ImportJava.util.Scanner;4 5 /*6 * Custom Exception test class7  */8  Public classStudentdemo {9      Public Static voidMain (string[] args) {TenScanner sc =NewScanner (system.in); OneSystem.out.println ("Please enter student results:"); A         intScore =sc.nextint (); -  -Teacher T =NewTeacher (); the         Try { - T.check (score); -}Catch(MyException e) { - e.printstacktrace (); +         } -     } +}

Android (Java) Study Note 84: Custom exception classes