java基础_传值与传址方法调用

public class PassTest {
	public static void changeValue(int a) {
		a = 20;
	}

	public static void changeValue(Integer b) {
		b = 20;
	}

	public static void changeObjectRef(MyDate my) {
		my = new MyDate(2008, 10, 28);
	}

	public static void changeObjectAttr(MyDate my) {
		my.setDay(4);
	}

	public static void main(String[] args) {
		int a = 10;
		changeValue(a);
		System.out.println("a=" + a);

		Integer b = new Integer(10);
		changeValue(b);
		System.out.println("b=" + b);

		MyDate date;
		date = new MyDate(1964, 7, 22);
		changeObjectRef(date);
		System.out.println("date=" + date);
		changeObjectAttr(date);
		System.out.println("date=" + date);
	}
}

// MyDate类
class MyDate {
	private int year;
	private int month;
	private int day;

	MyDate(int year, int month, int day) {
		this.year = year;
		this.month = month;
		this.day = day;
	}

	public void setDay(int day) {
		this.day = day;
	}

	public String toString() {
		return this.year + "-" + this.month + "-" + this.day;
	}
}