11 A B

package cn.lyhh; class Person{ private String name; private int age; static String city = "A城"; public Person(String name,int age) { this.name = name; this.age = age; } public String getInfo() { return "姓名:" + this.name + ",年龄:" + this.age + ",城市:" + city; } } public class L { public static void main(String[] args) { Person per1 = new Person("张三",30); Person per2 = new Person("李四",31); Person per3 = new Person("王五",30); System.out.println("======修改信息之前======"); System.out.println(per1.getInfo()); System.out.println(per2.getInfo()); System.out.println(per3.getInfo()); System.out.println("======修改信息之后======"); Person.city = "B城"; System.out.println(per1.getInfo()); System.out.println(per2.getInfo()); System.out.println(per3.getInfo()); } }

 

package cn.lyhh; class La{ private static La instance = new La(); private La() { } public static La getInstance() { return instance; } public void print() { System.out.println("hello world!!!"); } } public class L { public static void main(String[] args) { La s = null; s = La.getInstance(); s.print(); } } package cn.lyhh; class La{ private static La instance = new La(); private La() { } public static La getInstance() { return instance; } public void print() { System.out.println("hello world!!!"); } } public class L { public static void main(String[] args) { La s = null; s = La.getInstance(); s.print(); } } package cn.lyh; class Person{ private String name; private static int count; public Person() { count++; this.name = "NONAME - " + count; } public Person(String name) { this.name = name; } public String getInfo() { return "姓名:" + this.name; } } public class Ly{ public static void main(String[] args) { System.out.println(new Person().getInfo()); System.out.println(new Person("A").getInfo()); System.out.println(new Person("B").getInfo()); System.out.println(new Person().getInfo()); } } package cn.lyh; class Person{ private String name; private static int count; public Person() { count++; System.out.println("产生了" + count + "个实例化"); } public String getInfo() { return "姓名:" + this.name; } } public class Y { public static void main(String[] args) { new Person(); new Person(); new Person(); new Person(); new Person(); } }

转载于:https://www.cnblogs.com/speater/p/8057193.html