项目1——家庭收支记账软件

工具类：

package project1;

import java.util.Scanner;

public class Utility {
    private static Scanner scanner = new Scanner(System.in);
    /**
     * 读入1-4
     */
    public static char readMenuSelection() {
        char c;
        while (true) {
            String str = readKeyBoard(1);
            c = str.charAt(0);
            if (c!='1'&&c!='2'&&c!='3'&&c!='4') {
                System.out.println("选择错误，请重新输入：");
            } else {
                break;
            }
        }
        return c;
    }

    /**
     * 输入收入和支出金额，不超过4位数
     */
    public static int readNumber() {
        int n;
        while (true) {
            String str = readKeyBoard(4);
            try {
                n = Integer.parseInt(str);
                break;
            } catch (NumberFormatException e) {
                System.out.println("数字输入错误，请重新输入：");
            }
        }
        return n;
    }

    /**
     * 收入和支出说明，不超过8位
     */
    public static String readString() {
        String str = readKeyBoard(8);
        return str;
    }

    /**
     * 确认选择，Y或N
     */
    public static char readConfirmSelection() {
        char c;
        while (true) {
            String str = readKeyBoard(8).toUpperCase();
            c = str.charAt(0);
            if (c=='Y'||c=='N') {
                break;
            } else {
                System.out.println("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.println("输入的长度（不大于"+limit+"）错误，请重新输入：");
                continue;
            } else {
                break;
            }
        }
        return line;
    }
}

主函数:

package project1;

public class FamilyAccount {
    public static void main(String[] args) {
        boolean isFlag = true;
        //用于记录用户的收入和支出详情
        String details = "收支\t\t账户金额\t\t收支金额\t\t说  明\n";
        //初始金额
        int balance = 10000;
        //收入或支出金额
        int money = 0;
        //收入或支出说明
        String info;
        while (isFlag) {
            System.out.println("----------------家庭收支记账软件----------------");
            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");
            System.out.println("                  请选择（1-4）");
            //获取用户的选择：1-4
            char selection = Utility.readMenuSelection();
            switch (selection) {
                case '1':
                    //System.out.println("1.收支明细");
                    System.out.println("----------------当前收支明细记录----------------");
                    System.out.println(details);
                    System.out.println("---------------------------------------------");
                    break;
                case '2':
                    //System.out.println("2.登记收入");
                    System.out.println("本次收入金额：");
                    money = Utility.readNumber();
                    System.out.println("本次收入说明：");
                    info = Utility.readString();
                    //处理balance
                    balance += money;
                    //处理deteils
                    details += "收入\t\t"+balance+"\t\t"+money+"\t\t\t"+info+"\n";
                    System.out.println("-------------------登记完成-------------------\n");
                    break;
                case '3':
                    //System.out.println("3.登记支出");
                    System.out.println("本次支出金额：");
                    money = Utility.readNumber();
                    System.out.println("本次支出说明：");
                    info = Utility.readString();
                    //处理balance
                    if (balance > money) {
                        balance -= money;
                        //处理deteils
                        details += "支出\t\t"+balance+"\t\t"+money+"\t\t\t"+info+"\n";
                    } else {
                        System.out.println("支出超出账户额度，支付失败");
                    }
                    System.out.println("-------------------登记完成-------------------\n");
                    break;
                case '4':
                    //System.out.println("4.退   出");
                    System.out.println("确认是否退出(Y/N)");
                    char isExit = Utility.readConfirmSelection();
                    if (isExit=='Y') {
                        isFlag = false;
                    }
                    //break;
            }
            //isFlag = false;
        }
    }
}