1.Utility模块

import java.util.Scanner;
/**Utility工具类：将不同的功能封装为方法，就是可以直接通过调用方法使用它的功能，而无需考虑具体的功能实现细节。*/
public class Utility {private static Scanner scanner = new Scanner(System.in);/**用于界面菜单的选择。该方法读取键盘，如果用户键入’1’-’4’中的任意字符，则方法返回。返回值为用户键入字符。*/public static char readMenuSelection() {char c;for (; ; ) {String str = readKeyBoard(1);c = str.charAt(0);if (c != '1' && c != '2' && c != '3' && c != '4') {System.out.print("选择错误，请重新输入：");}elsebreak;}return c;}/**用于收入和支出金额的输入。该方法从键盘读取一个不超过4位长度的整数，并将其作为方法的返回值。*/public static int readNumber() {int n;for (; ; ) {String str = readKeyBoard(4);try {n = Integer.parseInt(str);break;} catch (NumberFormatException e) {System.out.print("数字输入错误，请重新输入：");}}return n;}/**用于收入和支出说明的输入。该方法从键盘读取一个不超过8位长度的字符串，并将其作为方法的返回值。*/public static String readString() {String str = readKeyBoard(8);return str;}/**用于确认选择的输入。该方法从键盘读取‘Y’或’N’，并将其作为方法的返回值。*/public static char readConfirmSelection() {char c;for (; ; ) {String str = readKeyBoard(1).toUpperCase();c = str.charAt(0);if (c == 'Y' || c == 'N') {break;} else {System.out.print("选择错误，请重新输入：");}}return c;}private static String readKeyBoard(int limit) {String line = "";while (scanner.hasNext()) {line = scanner.nextLine();if (line.length() < 1 || line.length() > limit) {System.out.print("输入长度（不大于" + limit + "）错误，请重新输入：");continue;}break;}return line;}
}

2. 账户模块

/*
阶段一的项目：记账软件的实现*/public class GuLiAccount {public static void main(String[] args) {boolean isFlag = true;//控制循环的结束//初始金额int balance = 10000;String info  = "";//记录收支说明while (isFlag) {System.out.println("-------斐秋记账软件---------\n");System.out.println("-------1、收支明细---------");System.out.println("-------2、登记收入---------");System.out.println("-------3、登记支出---------");System.out.println("-------4、退   出---------\n");System.out.println("------- 请选择（1-4）：");char selection = Utility.readMenuSelection(); //readMenuSelectionswitch (selection) {case '1':System.out.println("------------------当前收支明细记录-------------------");System.out.println("收支\t账户金额\t收支金额\t说   明");System.out.println(info);System.out.println("--------------------------------------------------");break;case '2':System.out.println("本次收入金额：");int money1 = Utility.readNumber();if (money1 > 0) {balance += money1;}System.out.print("本次收入说明：");String addDesc = Utility.readString();info += "收入\t" + balance + "\t\t" + money1 + "\t" + addDesc + "\n";System.out.println("------------------------登记完成-------------------");break;case '3':System.out.println("本次支出金额：");int money2 = Utility.readNumber();if (money2 > 0 && balance >= money2){balance -= money2;}System.out.println("本次支出说明：");String minusDesc = Utility.readString();info += "支出\t" + balance + "\t\t" + money2 + "\t\t" + minusDesc + "\n";System.out.println("------------------------登记完成--------------------------");break;case '4':System.out.print("\n确认是否退出（Y/N）：");char isExit = Utility.readConfirmSelection();if (isExit == 'Y'){isFlag = false;} else {}break;}}}
}