實(shí)驗(yàn)9自定義異常的使用

1、1）在定義一個(gè)銀行類Bank時(shí),有deposit、withdraw、showBalance等方法。若取錢(qián)數(shù)大于余額則作為異常處理(InsufficientFundsException)。產(chǎn)生異常的條件是余額少于取額，因此是否拋出異常要判斷條件，要定義好自己的異常類。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+非法取款余額;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）定義Triangle類用于表示三角形，其任意兩個(gè)邊的和必須大于第三條邊。定義IllegalTriangleException用于聲明任何違反以上規(guī)則的輸入。Triangle類的構(gòu)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）要求聲明定義2個(gè)異常類：NoLetterException類和NoDigitException類。再定義一個(gè)People類，該類中的voidprintLetter(charc)throws方法拋

7、出NoLetterException異常，voidprintDigit(charc)方法拋出NoDigitException異常。主類ExceptionExample對(duì)2個(gè)方法分別測(cè)試。packageex93;publicclassExceptionExamplepublicstaticvoidmain(Stringargs)Peoplepeople=newPeople();for(inti=0;i128;i+)trypeople.printLetter(char)i);/調(diào)用people對(duì)象的printLetter方法并處理異常catch(NoLetterExceptione)System.

8、out.println(發(fā)生異常:+e.getMessage();e.print();for(inti=0;i=a&c=0&c=9)thrownewNoDigitException();elseSystem.out.println(請(qǐng)輸出該字符：+c);4）CircleArea類是一個(gè)命令行輸入的計(jì)算器，用于計(jì)算圓的面積，程序從命令行接收半徑。如果命令行輸入的是非數(shù)字，則程序拋出異常，顯示消息通知用戶必須輸入數(shù)字。e類用于表示三角形，其任意兩個(gè)邊的和必須大于第三條邊。定義IllegalTriangleException用于聲明任何違反以上規(guī)則的輸入。Triangle類的構(gòu)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