用java生成存储多个员工信息包括工号、姓名、年龄入职时间打印所有员工姓名并输出 员工的 个数。使用三种方式

方式一：使用数组存储员工信息

public class Employee {
    private int id;
    private String name;
    private int age;
    private Date hireDate;

    public Employee(int id, String name, int age, Date hireDate) {
        this.id = id;
        this.name = name;
        this.age = age;
        this.hireDate = hireDate;
    }

    public String getName() {
        return name;
    }
}

public class Main {
    public static void main(String[] args) {
        Employee[] employees = new Employee[3];
        employees[0] = new Employee(1, "张三", 22, new Date());
        employees[1] = new Employee(2, "李四", 25, new Date());
        employees[2] = new Employee(3, "王五", 28, new Date());

        System.out.println("员工姓名：");
        for (Employee employee : employees) {
            System.out.println(employee.getName());
        }
        System.out.println("员工个数：" + employees.length);
    }
}

方式二：使用集合存储员工信息

public class Employee {
    private int id;
    private String name;
    private int age;
    private Date hireDate;

    public Employee(int id, String name, int age, Date hireDate) {
        this.id = id;
        this.name = name;
        this.age = age;
        this.hireDate = hireDate;
    }

    public String getName() {
        return name;
    }
}

public class Main {
    public static void main(String[] args) {
        List<Employee> employees = new ArrayList<>();
        employees.add(new Employee(1, "张三", 22, new Date()));
        employees.add(new Employee(2, "李四", 25, new Date()));
        employees.add(new Employee(3, "王五", 28, new Date()));

        System.out.println("员工姓名：");
        for (Employee employee : employees) {
            System.out.println(employee.getName());
        }
        System.out.println("员工个数：" + employees.size());
    }
}

方式三：使用Map存储员工信息

public class Employee {
    private int id;
    private String name;
    private int age;
    private Date hireDate;

    public Employee(int id, String name, int age, Date hireDate) {
        this.id = id;
        this.name = name;
        this.age = age;
        this.hireDate = hireDate;
    }

    public String getName() {
        return name;
    }
}

public class Main {
    public static void main(String[] args) {
        Map<Integer, Employee> employeeMap = new HashMap<>();
        employeeMap.put(1, new Employee(1, "张三", 22, new Date()));
        employeeMap.put(2, new Employee(2, "李四", 25, new Date()));
        employeeMap.put(3, new Employee(3, "王五", 28, new Date()));

        System.out.println("员工姓名：");
        for (Employee employee : employeeMap.values()) {
            System.out.println(employee.getName());
        }
        System.out.println("员工个数：" + employeeMap.size());
    }
}
``