实验9自定义异常的使用

1、1）在定义一个银行类Bank时,有deposit、withdraw、showBalance等方法。若取钱数大于余额则作为异常处理(InsufficientFundsException)。产生异常的条件是余额少于取额，因此是否抛出异常要判断条件，要定义好自己的异常类。packageex91;publicclassBankpublicdoubletotal=0;Bank(doubled)total=d;publicvoiddeposit(doubled)total+=d;publicvoidwithdraw(doubled)total-=d;publicvoidshowBalance()Syste

2、m.out.println(total);packageex91;publicclassBankExceptionextendsExceptionStringmessage;BankException(doubled)message=d+非法取款余额;publicStringgetMessage()returnmessage;packageex91;importjava.util.Scanner;publicclassBankTest/*paramargs*/publicstaticvoidmain(Stringargs)throwsBankExceptionTODOAuto-generate

3、dmethodstubBankbk=newBank(1236.123);bk.showBalance();Scannersc=newScanner(System.in);inti=sc.nextInt();bk.withdraw(i);if(bk.total0)BankExceptionbe=newBankException(i);throw(be);elsebk.showBalance();2）定义Triangle类用于表示三角形，其任意两个边的和必须大于第三条边。定义IllegalTriangleException用于声明任何违反以上规则的输入。Triangle类的构造方法如下：publi

4、cTriangle(doubleside1,doubleside2,doubleside3)throwsIllegalTriangleExceptionImplementitpackageex92;importjava.io.IOException;classIllegalTriangleExceptionextendsException/privatestaticfinallongserialVersionUID=1L;packageex92;importjava.io.IOException;publicclassTestpublicstaticvoidmain(Stringargs)th

5、rowsIOExceptionTrianglet1;tryt1=newTriangle(3,1,2);catch(IllegalTriangleExceptione)e.printStackTrace();System.out.println(不合法的三角形);return;System.out.println(side1=+t1.side1+,side2=+t1.side2+,side3=+t1.side3);packageex92;classTriangledoubleside1;doubleside2;doubleside3;publicTriangle(doubleside1,doub

6、leside2,doubleside3)throwsIllegalTriangleExceptionsuper();if(side1+side2=side3|side1+side3=side2|side2+side3=side1)thrownewIllegalTriangleException();this.side1=side1;this.side2=side2;this.side3=side3;3）要求声明定义2个异常类：NoLetterException类和NoDigitException类。再定义一个People类，该类中的voidprintLetter(charc)throws方法抛

7、出NoLetterException异常，voidprintDigit(charc)方法抛出NoDigitException异常。主类ExceptionExample对2个方法分别测试。packageex93;publicclassExceptionExamplepublicstaticvoidmain(Stringargs)Peoplepeople=newPeople();for(inti=0;i128;i+)trypeople.printLetter(char)i);/调用people对象的printLetter方法并处理异常catch(NoLetterExceptione)System.

8、out.println(发生异常:+e.getMessage();e.print();for(inti=0;i=a&c=0&c=9)thrownewNoDigitException();elseSystem.out.println(请输出该字符：+c);4）CircleArea类是一个命令行输入的计算器，用于计算圆的面积，程序从命令行接收半径。如果命令行输入的是非数字，则程序抛出异常，显示消息通知用户必须输入数字。e类用于表示三角形，其任意两个边的和必须大于第三条边。定义IllegalTriangleException用于声明任何违反以上规则的输入。Triangle类的构造方法如下：publi

9、cTriangle(doubleside1,doubleside2,doubleside3)throwsIllegalTriangleException/Implementitpackageex94;importjava.io.BufferedReader;importjava.io.InputStreamReader;publicclassTestCirclepublicstaticvoidmain(Stringargs)while(true)System.out.println(Pleaseenteraradiusofthecircle:);tryBufferedReaderbr=newBufferedReader(newInputStreamReader(System.in);doubleradius=Double.valueOf(br.readLine().trim();System.out.println(Yourentertheradiusis:+radius);doublearea=Math.PI*ra