java 构造器

权限修饰符 构造器名(参数列表){
    //  初始化代码体  
}

public class PersonTest {
	public static void main(String[] args) {
		Person p = new Person();
		System.out.println(p.age); // 0 默认值；
	}
}
class Person{
	int age; 
　　　　//类体存在隐式空参构造器 权限修饰符跟class相同
}

public class PersonTest {
	public static void main(String[] args) {
		Person p = new Person();
		System.out.println(p.age); // 0
	}
}
class Person{
	int age;
	public Person() {
		
	}
}

public class PersonTest {
	public static void main(String[] args) {
		Person p1 = new Person(20);
		System.out.println("p1 age is :" + p1.getAge());
		Person p2 = new Person("李狗蛋");
		System.out.println("p2 name is :" + p2.getName());
		Person p3 = new Person(18,"李狗蛋");
		System.out.println("p3 age is :" + p3.getAge() + "\t name is: " + p3.getName());
		
	}
}
class Person{
	private int age;
	private String name;
	public Person(int age) {
		this.age = age;
	}
	public Person(String name) {
		this.name = name;
	}
	public Person(int age,String name) {
		this.age = age;
		this.name = name;
	}
	public int getAge() {
		return age;
	}
	public String getName() {
		return name;
	}
}

public class PersonTest {
	public static void main(String[] args) {
		Person p = new Person("李老八");
		System.out.println("name"+p.getName());
		p.setName("轩子巨二兔");
		System.out.println("After setting name:" + p.getName());		
	}
}
class Person{
	private String name;   // null(默认) => “李老八”(构造器) => “轩子老师”（操作赋值）
	public Person(String name) {
		this.name = name;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
}