家庭记账软件

FamilyAccount

        int balance = 10000;//生活基本金额
        String details = "描述\t账户金额\t\t流水金额\t\t说 明\n";
        boolean loopFlag = true;//控制循环的标记

        do {
            System.out.println("\n-----------------家庭收支记账软件-----------------\n");
            System.out.println("\t\t\t\t 1 收支明细");
            System.out.println("\t\t\t\t 2 登记收入");
            System.out.println("\t\t\t\t 3 登记支出");
            System.out.println("\t\t\t\t 4 退 出");
            System.out.println();
            System.out.print("\t\t\t\t 请选择(1-4)：");
            
            //此方法接收 1-4 任意字符
            char ch = Utility.readMenuSelection();
            
            switch (ch) {
                    //收支明细
                case '1':
                    System.out.println("-----------------当前收支明细记录-----------------");
                    System.out.println(details);
                    break;
                    
                    //登记收入
                case '2':
                    System.out.print("本次收入金额：");
                    int amount1 = Utility.readNumber();//接收3位数的整数
                    System.out.print("本次收入说明：");
                    String str1 = Utility.readString();//收入的描述
                    balance += amount1;
                    details += "收入\t" + balance + "\t\t" + amount1 + "\t\t\t" + str1 + "\n";
                    break;
                    
                    //登记支出
                case '3':
                    System.out.print("本次支出金额：");
                    int num2 = Utility.readNumber();//接收3位数的整数
                    System.out.print("本次支出说明：");
                    String str2 = Utility.readString();//支出的描述
                    balance -= num2;
                    details += "支出\t" + balance + "\t\t" + num2 + "\t\t" + str2 + "\n";
                    break;
                   
                    //退出
                case '4':
                    System.out.print("请确认是否退出(y/n)：");
                    char yn = Utility.readConfirmSelection();
                    if (yn == 'Y') {
                        loopFlag = false;
                    }
                    break;
            }
        } while (loopFlag);

Utility

        package com.dream;

        import java.util.*;

        public class Utility {
            private static Scanner scanner = new Scanner(System.in);

            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：");
                    } else break;
                }
                return c;
            }

            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;
            }

            public static String readString() {
                String str = readKeyBoard(8);
                return str;
            }

            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;
            }
        }