布尔型 boolean

boolean isPaid = true;             // 是否已支付
boolean inStock = true;            // 是否有货
boolean needReservation = true;    // 是否需要预约
boolean isPeakSeason = false;      // 是否旺季
boolean fullAttendance = true;     // 是否满勤
boolean hasFever = false;          // 是否发热
boolean isGraduated = false;       // 是否毕业
boolean isExcellent = true;        // 是否优秀
boolean isSignature = true;        // 是否招牌菜
boolean isFull = true;             // 是否满油

/**
 * 飞翔科技 - boolean 类型演示
 * 场景：飞翔商城的订单支付状态与库存校验
 */
public class BooleanOrderDemo {
    public static void main(String[] args) {
        // 订单状态
        boolean isPaid = true;
        boolean inStock = true;
        boolean isVIP = true;
        boolean needShipping = true;
        boolean hasCoupon = false;
        
        int buyCount = 2;
        float price = 188.88f;
        float shippingFee = 8.8f;
        
        // 逻辑判断
        boolean canPurchase = inStock && (buyCount > 0);
        boolean freeShipping = isVIP || (price * buyCount >= 200.00f);
        boolean needPay = !isPaid;
        
        float totalPrice = price * buyCount;
        float finalShipping = freeShipping ? 0.0f : shippingFee;
        float totalAmount = totalPrice + finalShipping;
        
        System.out.println("【飞翔商城 - 订单状态】");
        System.out.println("商品库存：" + (inStock ? "有货" : "缺货"));
        System.out.println("支付状态：" + (isPaid ? "已支付" : "未支付"));
        System.out.println("VIP会员：" + (isVIP ? "是" : "否"));
        System.out.println("免运费：" + (freeShipping ? "是" : "否"));
        System.out.println("可用优惠券：" + (hasCoupon ? "有" : "无"));
        System.out.println("可购买：" + (canPurchase ? "是" : "否"));
        System.out.println("\n商品总价：¥" + totalPrice);
        System.out.println("运费：¥" + finalShipping);
        System.out.println("应付总额：¥" + totalAmount);
    }
}

/**
 * 飞翔科技 - boolean 复合判断演示
 * 场景：员工考勤与权限校验系统
 */
public class BooleanAttendanceDemo {
    public static void main(String[] args) {
        // 员工考勤信息
        boolean fullAttendance = true;     // 是否满勤
        boolean salaryPaid = true;         // 工资是否已发
        boolean hasPermission = true;      // 是否有薪资系统权限
        boolean isWeekend = false;         // 是否周末
        
        // 绩效条件
        int performanceScore = 100;
        boolean excellentPerformance = performanceScore >= 90;
        boolean goodPerformance = performanceScore >= 75 && performanceScore < 90;
        
        // 复合逻辑判断
        boolean yearEndBonus = fullAttendance && excellentPerformance;
        boolean canViewSalary = hasPermission && salaryPaid;
        boolean needOvertime = isWeekend && performanceScore < 75;
        
        // 短路的实际应用
        boolean accessGranted = hasPermission && checkDatabaseConnection();
        
        System.out.println("【飞翔科技 - 考勤与权限】");
        System.out.println("满勤：" + fullAttendance);
        System.out.println("绩效分：" + performanceScore + " → " 
                           + (excellentPerformance ? "优秀" : goodPerformance ? "良好" : "待改进"));
        System.out.println("年终奖资格：" + (yearEndBonus ? "有" : "无"));
        System.out.println("薪资查看权限：" + (canViewSalary ? "可查看" : "无权限"));
        System.out.println("需要加班：" + (needOvertime ? "是" : "否"));
        
        System.out.println("\n【Boolean工具方法】");
        System.out.println("Boolean.TRUE: " + Boolean.TRUE);
        System.out.println("Boolean.FALSE: " + Boolean.FALSE);
        System.out.println("Boolean.parseBoolean(\"true\"): " + Boolean.parseBoolean("true"));
        System.out.println("Boolean.parseBoolean(\"TrUe\"): " + Boolean.parseBoolean("TrUe"));  // 不区分大小写
        System.out.println("Boolean.parseBoolean(\"yes\"): " + Boolean.parseBoolean("yes"));    // false！只认"true"
    }
    
    static boolean checkDatabaseConnection() {
        // 模拟数据库连接检查
        System.out.println("  → 正在检查数据库连接...");
        return true;
    }
}

// ❌ 常见C转Java的错误：用0和1表示真假
// int flag = 1;
// if (flag) { ... }  // 编译错误！int不能作为boolean条件

// ❌ 错误：boolean参与算术
boolean b = true;
// int result = b + 1;     // 编译错误！
// int result = b ? 1 : 0; // ✅ 如果需要转为int，用三元运算符

// ❌ 错误：if(1) 这种写法
// if (1) { }  // 编译错误

// ✅ 正确：if 条件必须是 boolean 表达式
boolean flag = true;
if (flag) {
    System.out.println("正确");
}

// ❌ 危险：parseBoolean 只认 "true"（不区分大小写）
boolean b1 = Boolean.parseBoolean("true");   // true
boolean b2 = Boolean.parseBoolean("false");  // false
boolean b3 = Boolean.parseBoolean("yes");    // false！（不是true！）
boolean b4 = Boolean.parseBoolean("1");      // false！
boolean b5 = Boolean.parseBoolean("");       // false！
boolean b6 = Boolean.parseBoolean(null);     // false！

// ✅ 如果需要更灵活的解析，自己写判断
// "yes"/"1"/"on" → true；"no"/"0"/"off" → false

// ❌ 危险：Boolean对象可能为null
Boolean paid = null;
if (paid == true) {   // NullPointerException？不会，但语义不对
    // paid==true 在paid为null时返回false（不抛异常）
}
if (paid) {  // NullPointerException！自动拆箱时paid为null
}

// ✅ 正确：先判空或用 Boolean.TRUE.equals()
if (Boolean.TRUE.equals(paid)) {
    // 安全
}

// ❌ 糟糕的命名
boolean flag = true;       // flag是什么？
boolean status = false;    // status是什么状态？
boolean b = true;          // 完全不知道含义

// ✅ 好的命名：is/has/can/should 前缀
boolean isPaid = true;           // 是否已支付
boolean hasPermission = false;   // 是否有权限
boolean canEdit = true;          // 是否可编辑
boolean shouldNotify = true;     // 是否应通知
boolean fullAttendance = true;   // 是否满勤
boolean needReservation = false; // 是否需要预约