练习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。

package chapter07_oop2.src.com.atguigu07.object.equals.exer1;/*** ClassName: Order* Package: chapter07_oop2.src.com.atguigu07.object.equals.exer1* Description:** @Author 小白* @Create 2024/4/3 9:20* @Version 1.0*/
public class Order {private  int orderId;private String orderName;public Order() {}public Order(int orderId, String orderName) {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;}//手写一个equals()@Overridepublic boolean equals(Object obj) {if (this == obj) {   //判断当前this对象和形参obj是否是同一个对象return true;}if (obj instanceof Order) {//判断obj是否是Order 如果是的话  我们就进行强转  好比动物类 在判断动物是否狗//如果是的话 在进行强转 把动物类转换成狗Order order = (Order) obj;return this.orderId == order.orderId && this.orderName.equals(order.orderName);}else {return false;}}
}

package chapter07_oop2.src.com.atguigu07.object.equals.exer1;/*** ClassName: OrderTest* Package: chapter07_oop2.src.com.atguigu07.object.equals.exer1* Description:** @Author 小白* @Create 2024/4/3 9:36* @Version 1.0*/
public class OrderTest {public static void main(String[] args) {Order order1 = new Order(1001, "orderAA");Order order2 = new Order(1001, "orderAA");System.out.println(order1.equals(order2));//trueOrder order3 = new Order(1002, new String("orderBB"));Order order4 = new Order(1002, new String("orderBB"));System.out.println(order3.equals(order4));  //true}}

练习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 EqualsTest {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");}}
}

还没有重equals

package chapter07_oop2.src.com.atguigu07.object.equals.exer2;/*** ClassName: MyDate* Package: chapter07_oop2.src.com.atguigu07.object.equals.exer2* Description:** @Author 小白* @Create 2024/4/3 9:57* @Version 1.0*/
public class MyDate {private  int day;private  int month;private  int year;public MyDate() {}public MyDate(int day, int month, int year) {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;}
}

package chapter07_oop2.src.com.atguigu07.object.equals.exer2;/*** ClassName: EqualsTest* Package: chapter07_oop2.src.com.atguigu07.object.equals.exer2* Description:** @Author 小白* @Create 2024/4/3 9:57* @Version 1.0*/
public class EqualsTest {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");}}}

 

 

重写后

package chapter07_oop2.src.com.atguigu07.object.equals.exer2;/*** ClassName: MyDate* Package: chapter07_oop2.src.com.atguigu07.object.equals.exer2* Description:** @Author 小白* @Create 2024/4/3 9:57* @Version 1.0*/
public class MyDate {private  int day;private  int month;private  int year;public MyDate() {}public MyDate(int day, int month, int year) {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;}@Overridepublic boolean equals(Object obj) {if(this == obj){return  true;}///如果地址不一样   判断obj是否等于MyDate  如果相等  进行强转   并判断各个属性是否相等if(obj instanceof  MyDate){MyDate  myDate = (MyDate) obj;return  this.year == myDate.year && this.month ==myDate.month &&this.day == myDate.day;}return  false;}
}

package chapter07_oop2.src.com.atguigu07.object.equals.exer2;/*** ClassName: EqualsTest* Package: chapter07_oop2.src.com.atguigu07.object.equals.exer2* Description:** @Author 小白* @Create 2024/4/3 9:57* @Version 1.0*/
public class EqualsTest {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//重写equals后  m1 is equal to m2} else {System.out.println("m1 is not equal to m2");}}}