第一题

1.定义一个Person类,要求有姓名和年龄,并且符合JavaBean标准,定义Student类继承Person,定义测试类,创建Student对象,要求创建Student对象的同时,指定Student对象的姓名为"张三",只能指定姓名不许指定年龄

class Person {
    private String name;
    private int age;
    public Person() {}
    public Person(String name) {
        this.name = name;
    }
    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }
    
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }

    public String toString() {
        return "Person{name = " + name + ", age = " + age + "}";
    }
}

class Student extends Person{
    public Student() {
    }
    public Student(String name) {
        super(name);
    }
}

public class Test {
    public static void main(String[] args) {
        Student student=new Student("张三");
    }
}

第二题

2.按照以下要求定义类

Animal 
	吃
	睡
Dog 
	吃  狗吃肉
	睡  狗趴着睡
	看门  
Cat  
	吃  猫吃鱼
	睡  猫躺着睡
	抓老鼠
Home 
	定义一个动物在家吃饭的方法 要求猫和狗都可以传入
定义测试类  测试 Home类在家吃饭的方法 

public class test{
    public static void main(String[] args) {
        new Home().inHomeEat(new Dog());
        new Home().inHomeEat(new Cat());
    }
}
abstract class Animal {
    public abstract void eat();
    public abstract void sleep();
}
class Home {
    void inHomeEat(Animal animal) {
        System.out.print("在家: ");
        animal.eat();
    }
}
class Dog extends Animal {
    @Override
    public void eat() {
        System.out.println("狗吃肉");
    }

    @Override
    public void sleep() {
        System.out.println("狗趴着睡");
    }

}
class Cat extends Animal {
    @Override
    public void eat() {
        System.out.println("猫吃鱼");
    }

    @Override
    public void sleep() {
        System.out.println("猫躺着睡");
    }
}

第三题

3.键盘录入一个字符串,判断这个字符串是否是对称的字符串 比如 abcba abba aabbebbaa 如果是打印"是对称的字符串",如果不是打印"不是对称的字符串"

public class test{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("输入一个字符串: ");
        String str = sc.nextLine();
        char[] charList = str.toCharArray();
        boolean b = check(charList);
        System.out.println(b?"是对称的字符串":"不是对称的字符串");
    }
    public static boolean check(char[] charList) {
        int maxIndex = charList.length - 1;
        for (int i = 0; i < charList.length / 2; i++) {
            if (charList[i] != charList[maxIndex]) {
                return false;
            }
            maxIndex--;
        }
        return true;
    }
}

第四题

4.将字符串 " we-like-java " 转换为 "EW-EKIL-AVAJ" 也就是去掉前后空格,并将每个单词反转.

        String string = "         we-like-java       ";
        String[] arr = string.trim().toUpperCase().split("-");
        for (int i = arr.length - 1; i >= 0; i--) {
            StringBuilder sb = new StringBuilder(arr[i]);
            arr[i] = sb.reverse().toString();
        }
        StringBuilder sb =new StringBuilder();
        for (int i = 0; i < arr.length; i++) {
            sb.append(arr[i]);
            if (i < arr.length - 1) {
                sb.append("-");
            }
        }
        System.out.println(sb);

第五题

**5.网络程序中,如聊天室,聊天软件等,经常需要对用户提交的内容进行敏感词过滤如"枪","军火"等,这些词都不可以在网上进行传播,需要过滤掉或者用其他词语替换.键盘录入一个字符串 将敏感词替换成 "*" **

        String[] blockKeys = {"枪", "军火"};
        System.out.print("输入要提交的内容: ");
        String comment = sc.nextLine();
        for (int i = 0; i < blockKeys.length; i++) {
            comment = comment.replaceAll(blockKeys[i],"*");
        }
        System.out.println(comment);

第六题

6.计算 987654321123456789000 除以 123456789987654321的值,注意这个结果为BigInteger类型,将BigInteger类型转换为字符串类型,然后转换为double类型.精确计算3120.25乘以1.25,注意这个结果为BigDecimal类型,同样转换为字符串类型,然后转换为double类型,然后获取这两个结果的最大值

BigInteger bint1 = new BigInteger("987654321123456789000");
BigInteger bint2 = new BigInteger("123456789987654321");
Double d1 = Double.parseDouble(bint1.divide(bint2).toString());
Double d2 = Double.parseDouble(new BigDecimal(3120.25/1.25).toString());
System.out.println("较大的值为: " + Math.max(d1,d2));

第七题

7.键盘录入一个生日的字符串(xxxx-xx-xx) 计算这个人活了多少天

        System.out.print("请输入您的生日(年-月-日): ");
        String personBirthday = sc.nextLine();
        DateFormat df = new SimpleDateFormat("yyyy-MM-dd");
        try {
            Date birthDay = df.parse(personBirthday);
            System.out.println(("您活了" + (new Date().getTime() - birthDay.getTime())/1000/60/60/24) + "天");
        } catch (ParseException e) {
            System.out.println("输入错误");
        }

第八题

8.键盘录入一个指定的年份,获取指定年份的2月有多少天

public class test{
    public static void main(String[] args) throws PrintDataException {
        System.out.print("请输入年份");
        String printYear = sc.nextLine();
        try{
            int intPrintYear = Integer.parseInt(printYear);
            if (intPrintYear < 0){
                throw new PrintDataException("输入数据错误");
            }
            Calendar c = Calendar.getInstance();
            c.set(intPrintYear, 2, 1);
            c.add(Calendar.DAY_OF_MONTH, -1);
            System.out.println(c.get(Calendar.DAY_OF_MONTH));
        } catch (NumberFormatException e) {
            System.out.println("输入错误");
        }
    }
}
class PrintDataException extends Exception {
    public PrintDataException() { super();}
    public PrintDataException(String message) {
        super(message);
    }
}

第九题

9.将"Hello AbcDe"这个字符串转换为一个byte类型的数组,将数组的后5个元素复制到一个长度为5的byte数组中,然后将数组中的元素进行降序排列,将数组中的前3个元素放入到一个新的长度为3的数组中,并升序排列,最后查找字符'c'代表数值在新数组中的索引位置(可以使用Arrays工具类)

byte[] byteArr1 = "Hello AbcDe".getBytes();
byte[] byteArr2 = new byte[5];
System.arraycopy(byteArr1,byteArr1.length - 5, byteArr2, 0, 5);
// 排序
Arrays.sort(byteArr2);
// 反转
for (int i = 0; i < byteArr2.length / 2; i++ ) {
    byte tmp = byteArr2[i];
    byteArr2[i] = byteArr2[byteArr2.length - 1 - i];
    byteArr2[byteArr2.length - 1 - i] = tmp;
}
byte[] byteArr3 = Arrays.copyOf(byteArr2, 3);
Arrays.sort(byteArr3);
for (int i = 0; i < byteArr3.length; i++) {
    if (byteArr3[i] == 'c') {
        System.out.println("c的索引为: " + i);
        break;
    }
}

第十题

10.定义一个Person类,,要求有年龄,提供get/set方法,要求设置年龄时,如果年龄小于0或者年龄大于200抛出"NoAgeException"异常,如果年龄正常则正常设置.

class NoAgeException extends Exception {
    public NoAgeException() {super();}
    public NoAgeException(String message) {
        super(message);
    }
}
class Person  {
    private int age;
    public int getAge() {
        return age;
    }
    public void setAge(int age) throws NoAgeException {
        if (age < 0 || age > 200){
            throw new NoAgeException();
        }
        this.age = age;
    }
}