一、枚举类
1、定义枚举类
public enum EnumNum01 {
SUCCESS, FAILED
}
新建一个类测试
public class TestEnum {
public static void main(String[] args) {
System.out.println(EnumNum01.SUCCESS);
System.out.println(EnumNum01.FAILED);
}
}
输出结果：
SUCCESS
FAILED
2、定义枚举类，加入一个值
public enum EnumNum02 {
A(1),B(2),C(3),D(4),E(5);
private int num;
EnumNum02(int num){
this.num=num;
}
public int getNum() {
return num;
}
public void setNum(int num) {
this.num = num;
}
}
新建一个类测试：
public class EnumTest02 {
public static void main(String args[]){
EnumNum02 b=EnumNum02.B;
System.out.println(b.getNum());
}
}
运行结果：
2
3、定义一个枚举类，加入两个值
public enum EnumNum01 {
A(1,"1801"),B(2,"1802"),C(3,"1803"),D(4,"1804");
private int num;
private String msg;
EnumNum01(int num,String msg){
this.num=num;
this.msg=msg;
}
public int getNum() {
return num;
}
public void setNum(int num) {
this.num = num;
}
public String getMsg() {
return msg;
}
public void setMsg(String msg) {
this.msg = msg;
}
}
新建一个测试类：
public class EnumTest01 {
public static void main(String args[]){
EnumNum01 a=EnumNum01.A;
System.out.println(a);
System.out.println(a.getNum());
System.out.println(a.getMsg());
}
}
运行结果：
A
1
1801
二、单实例
1、IDEA默认创建的单例
public class Singleton01 {
private static Singleton01 ourInstance = new Singleton01();
public static Singleton01 getInstance() {
return ourInstance;
}
private Singleton01() {
}
}
2、测试
（1）、新增加一个方法
public class Singleton01 {
private static Singleton01 ourInstance = new Singleton01();
public static Singleton01 getInstance() {
return ourInstance;
}
private Singleton01() {
System.out.println("这是无参构造方法......");
}
public void print(){
System.out.println("这是单例中增加的方法......");
}
}
** （2）、新建一个类测试**
public class SingletonTest {
public static void main(String args[]){
Singleton01 singleton01=Singleton01.getInstance();
singleton01.print();
}
}
运行结果：
这是无参构造方法......
这是单例中增加的方法......
