equals()方法练习

package nine;

/**
 * 1.编写Order类，有int型的orderId，String型的OrderName，相应的getter()和setter()方法，两个参数的构造器，
 * 重写父类的equals()方法：public boolean equals(Object obj)，并判断测试类中创建的两个对象是否相等。
 */
public class TestOrder {
	public static void main(String[] args) {
		Order o1 = new Order(1001, "AA");
		Order o2 = new Order(1001, "AA");
		System.out.println(o1 == o2);// false
		System.out.println(o1.equals(o2));// false --->true
	}
}

class Order {
	private int orderId;
	private String orderName;

	public Order(int orderId, String orderName) {
		super();
		this.orderId = orderId;
		this.orderName = orderName;
	}

	public int getOrderId() {
		return orderId;
	}

	public void setOrderId(int orderId) {
		this.orderId = orderId;
	}

	public String getOrderName() {
		return orderName;
	}

	public void setOrderName(String orderName) {
		this.orderName = orderName;
	}
	//比较两个 Order 对象的属性是否完全相同。相同的话，返回 true。
//	public boolean equals(Object obj) {
//		if (this == obj) {
//			return true;
//		} else if (obj instanceof Order) {
//			Order o1 = (Order) obj;
//			return this.orderId == o1.orderId
//					&& this.orderName.equals(o1.orderName);
//		} else {
//			return false;
//		}
//	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		Order other = (Order) obj;
		if (orderId != other.orderId)
			return false;
		if (orderName == null) {
			if (other.orderName != null)
				return false;
		} else if (!orderName.equals(other.orderName))
			return false;
		return true;
	}
	
}

package nine;

/**
 2.请根据以下代码自行定义能满足需要的MyDate类,在MyDate类中覆盖equals方法，
 使其判断当两个MyDate类型对象的年月日都相同时，结果为true，否则为false。
 public boolean equals(Object o)
 */
public class TestMyDate {
	public static void main(String[] args) {
		MyDate m1 = new MyDate(14, 3, 1976);
		MyDate m2 = new MyDate(14, 3, 1976);

		if (m1 == m2) {
			System.out.println("m1 == m2");
		} else {
			System.out.println("m1 != m2"); // m1 != m2
		}

		if (m1.equals(m2)) {
			System.out.println("m1 is equal to m2");
			// m1 is equal to m2
		} else {
			System.out.println("m1 is not equal to m2");
		}
	}
}

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

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

	public int getDay() {
		return day;
	}

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

	public int getMonth() {
		return month;
	}

	public void setMonth(int month) {
		this.month = month;
	}

	public int getYear() {
		return year;
	}

	public void setYear(int year) {
		this.year = year;
	}
	//手动生成的
//	public boolean equals(Object obj) {
//		if (this == obj) {
//			return true;
//		} else if (obj instanceof MyDate) {
//			MyDate m = (MyDate) obj;
//			return this.day == m.day && this.month == m.month
//					&& this.year == m.year;
//		} else {
//			return false;
//		}
//	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		MyDate other = (MyDate) obj;
		if (day != other.day)
			return false;
		if (month != other.month)
			return false;
		if (year != other.year)
			return false;
		return true;
	}
	

}