[JAVA] Object 클래스 객체 사용

객체를 문자열로 변환하기

class Point{
	int x, y;
	Point(int x, int y){
		this.x = x;
		this.y = y;
	}
	
	@Override
	public String toString() {
		return "Point("+x+","+y+")";
	}
	
}

public class ObjectEx {
	static void print(Object obj) {
		System.out.println(obj.getClass());
		System.out.println(obj.hashCode());
		System.out.println(obj.toString());
		System.out.println(obj);
	}
	
	public static void main(String[] args) {
		Point p = new Point(2, 3);
		print(p);
	}

}

 

결과값 스트링은 역시 Point(2,3)으로 출력됨.

 

equal 비교

class Point{
	int x, y;
	Point(int x, int y){
		this.x = x;
		this.y = y;
	}
	
	@Override
	public String toString() {
		return "Point("+x+","+y+")";
	}
	
}

public class ObjectEx {
	static void print(Object obj) {
		Point p = new Point(2, 3);
		System.out.println(obj.getClass());
		System.out.println(obj.hashCode());
		System.out.println(obj.toString());
		System.out.println(obj);
        System.out.println("p: "+p.hashCode());
		System.out.println(obj == p);
		System.out.println(obj.equals(p));
	}
	
	public static void main(String[] args) {
		Point p = new Point(2, 3);
		print(p);
	}

}

결과

 

기본 p를 변형한다면

class Point{
	int x, y;
	Point(int x, int y){
		this.x = x;
		this.y = y;
	}
	
	@Override
	public String toString() {
		return "Point("+x+","+y+")";
	}

	@Override
	public boolean equals(Object obj) {
		Point p2 = new Point(2, 3);
		if(p2.x == x && p2.y == y)
			return true;
		else
			return false;
	}
}

public class ObjectEx {
	static void print(Object obj) {
		Point p = new Point(2, 3);
		System.out.println(obj.getClass());
		System.out.println(obj.hashCode());
		System.out.println(obj.toString());
		System.out.println(obj);
		System.out.println("p: "+p.hashCode());
		System.out.println(obj == p);
		System.out.println(obj.equals(p));
	}
	
	public static void main(String[] args) {
		Point p = new Point(2, 3);
		print(p);
	}

}