Java核心技术-对象与类 程序清单4-3

public class StaticTest {
    public static void main(String[] args) {
        Employee[] staff = new Employee[3];
        //创建数组 staff 数组长度为3
        staff[0] = new Employee("Tom",40000);
        staff[1] = new Employee("Dick", 60000);
        staff[2] = new Employee("Harry", 65000);
        //使用for each 输出数组内的元素
        for(Employee e : staff){
            e.setId();
            System.out.println("name=" + e.getName() + ",id=" + e.getId() + ",salary=" + e.getSalary());
        }
        //采用public void setId() 来得到每一个员工的Id
        int n = Employee.getNextId();
        System.out.println("Next available id=" + n);
    }
}


class Employee{
    //设置静态域 nextId等于1
    private static int nextId = 1;

    private String name;
    private double salary;
    private int id;

    public Employee(String n, double s){
        name = n;
        salary = s;
        id = 0;
    }
    //得到员工的名字 并返回
    public String getName(){
        return name;
    }
    //得到员工的工资 并返回
    public double getSalary() {
        return salary;
    }
    //得到员工的Id 并返回
    public int getId(){
        return id;
    }
    //下一个员工Id的方法
    public void setId(){
        id = nextId;
        nextId++;
    }
    //得到下一个员工的Id 并返回
    public static int getNextId(){
        return nextId;
    }
    //测试Employee类 运行是否正确
    public static void main(String[] args) {
        Employee e = new Employee("Harry", 50000);
        System.out.println(e.getName() + " " + e.getSalary());
    }
}

输出结果为：

name=Tom,id=1,salary=40000.0
name=Dick,id=2,salary=60000.0
name=Harry,id=3,salary=65000.0
Next available id=4