Java基础-day09-基础题-对象&类&封装 1.定义手机类并测试 代码实现: package StudentJavaSEday09; //定义手机类 public class Phone { //品牌 String brand; //价格 int price; //颜色 String color;
//打电话 public void call(String name) { System.out.println("给"+name+"打电话"); }
//发短信 public void sendMessage() { System.out.println("群发短信"); } } package StudentJavaSEday09; public class TestPhone { public static void main(String[] args) { // 创建对象 Phone p = new Phone(); // 输出成员变量值 System.out.println("品牌:" + p.brand);// null System.out.println("价格:" + p.price);// 0 System.out.println("颜色:" + p.color);// null System.out.println("------------"); // 给成员变量赋值 p.brand = "锤子"; p.price = 2999; p.color = "棕色"; // 再次输出成员变量值 System.out.println("品牌:" + p.brand);// 锤子 System.out.println("价格:" + p.price);// 2999 System.out.println("颜色:" + p.color);// 棕色 System.out.println("------------"); // 调用成员方法 p.call("唐嫣"); p.sendMessage(); } } 运行结果: 2.一个对象的内存图 定义一个手机类: 代码实现: package StudentJavaSEday09; public class Phone2 { public static void main(String[] args) { Phone p = new Phone(); System.out.println(p.brand + "---" + p.price + "---" + p.color); p.brand = "锤子"; p.price = 2999; p.color = "棕色"; System.out.println(p.brand + "---" + p.price + "---" + p.color); p.call("林青霞"); p.sendMessage(); } } 运行结果: 内存图解: 3.两个对象,引用同一个方法内存图 代码实现: package StudentJavaSEday09; public class Phone3 { public static void main(String[] args) { Phone p1 = new Phone(); p1.brand = "小米5s"; p1.price = 1999; p1.color = "银色"; System.out.println(p1.brand + "---" + p1.price + "---" + p1.color); p1.call("林青霞"); p1.sendMessage(); Phone p2 = new Phone(); p2.brand = "IPhone7S"; p2.price = 7999; p2.color = "土豪金"; System.out.println(p2.brand + "---" + p2.price + "---" + p2.color); p2.call("张曼玉"); p2.sendMessage(); } } 运行结果: 内存图解: 4.两个引用,指向同一个对象 代码实现: package StudentJavaSEday09; public class Phone4 { public static void main(String[] args) { Phone p1 = new Phone(); p1.brand = "OPPO"; p1.price = 2999; p1.color = "白色"; System.out.println(p1.brand + "---" + p1.price + "---" + p1.color); Phone p2 = p1; p2.brand = "魅族"; p2.price = 1999; p2.color = "蓝色"; System.out.println(p1.brand + "---" + p1.price + "---" + p1.color); System.out.println(p2.brand + "---" + p2.price + "---" + p2.color); } } 运行结果: 内存图解: |
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