ConstructorTest

public class ConstructorTest {

    /**
     * 重载构造器
     * 用this（...）调用另一个构造器
     * 无参数构造器
     * 对象初始化块
     * 静态初始化块
     * 实例域初始化
     */
    
    public static void main(String[] args) {
        // fill the staff array with three Employee objects
        Employee[] staff = new Employee[3];
        
        staff[0] = new Employee("Harry", 4000);
        staff[1] = new Employee(60000);
        staff[2] = new Employee();
        
        // print out information about all Employee objects
        for (Employee e : staff) {
            System.out.println("name = "+e.getName()+", id = " + e.getId()+", salary = "+e.getSalary());
            
        }
    }
    
}

class Employee
{
    private static int nextId;
    
    private int id;
    private String name = "";     // instance field initialization
    private double salary;
    
    static
    {
        Random generator = new Random();
        // set nextId to a random number between 0 and 9999
        nextId = generator.nextInt(10000);
    }
    
    // object initialization block
    {
        id = nextId;
        nextId++;
    }
    
    // three overloaded constructors
    public Employee(String n, double s)
    {
        name = n;
        salary = s;
    }
    
    public Employee(double s)
    {
        // calls the Employee(String, double) constructor
        this("Employee #" + nextId, s);
    }
    
    // the default constructor
    public Employee()
    {
        // name initialized to "" --see above
        // salary not explicitly set --initialized to 0
        // id initialized in initialization block
    }

    public int getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public double getSalary() {
        return salary;
    }
    
    
}

name = Harry, id = 8654, salary = 4000.0
name = Employee #8655, id = 8655, salary = 60000.0
name = , id = 8656, salary = 0.0