java基础枚举和注解

public class TestSeason {
public static void main(String[] args) {
Season spring = Season.SPRING;
System.out.println(spring);
spring.show();
System.out.println(spring.getSeasonName());
}
}
//枚举类
class Season{
//1.提供类的属性，声明为private final
private final String seasonName;
private final String seasonDesc;
//2.声明为final的属性，在构造器中初始化。
private Season(String seasonName,String seasonDesc){
this.seasonName = seasonName;
this.seasonDesc = seasonDesc;
}
//3.通过公共的方法来调用属性
public String getSeasonName() {
return seasonName;
}
public String getSeasonDesc() {
return seasonDesc;
}
//4.创建枚举类的对象:将类的对象声明public static final
public static final Season SPRING = new Season("spring", "春暖花开");
public static final Season SUMMER = new Season("summer", "夏日炎炎");
public static final Season AUTUMN = new Season("autumn", "秋高气爽");
public static final Season WINTER = new Season("winter", "白雪皑皑");
@Override
public String toString() {
return "Season [seasonName=" + seasonName + ", seasonDesc="
+ seasonDesc + "]";
}
public void show(){
System.out.println("这是一个季节");
}
}

/*
* 一、枚举类
* 1.如何自定义枚举类
* 2.如何使用enum关键字定义枚举类
*     >常用的方法:values() valueOf(String name)
*     >如何让枚举类实现接口:可以让不同的枚举类的对象调用被重写的抽象方法，执行的效果不同。（相当于让每个对象重写抽象方法）
*/
public class TestSeason1 {
public static void main(String[] args) {
Season1 spring = Season1.SPRING;
System.out.println(spring);
spring.show();
System.out.println(spring.getSeasonName());

System.out.println();
//1.values()
Season1[] seasons = Season1.values();
for(int i = 0;i < seasons.length;i++){
System.out.println(seasons[i]);
}
//2.valueOf(String name):要求传入的形参name是枚举类对象的名字。
//否则，报java.lang.IllegalArgumentException异常
String str = "WINTER";
Season1 sea = Season1.valueOf(str);
System.out.println(sea);
System.out.println();

Thread.State[] states = Thread.State.values();
for(int i = 0;i < states.length;i++){
System.out.println(states[i]);
}
sea.show();

}
}
interface Info{
void show();
}
//枚举类
enum Season1 implements Info{
SPRING("spring", "春暖花开"){
public void show(){
System.out.println("春天在哪里？");
}
},
SUMMER("summer", "夏日炎炎"){
public void show(){
System.out.println("生如夏花");
}
},
AUTUMN("autumn", "秋高气爽"){
public void show(){
System.out.println("秋天是用来分手的季节");
}
},
WINTER("winter", "白雪皑皑"){
public void show(){
System.out.println("冬天里的一把火");
}
};

private final String seasonName;
private final String seasonDesc;

private Season1(String seasonName,String seasonDesc){
this.seasonName = seasonName;
this.seasonDesc = seasonDesc;
}
public String getSeasonName() {
return seasonName;
}
public String getSeasonDesc() {
return seasonDesc;
}

@Override
public String toString() {
return "Season [seasonName=" + seasonName + ", seasonDesc="
+ seasonDesc + "]";
}
//	public void show(){
//		System.out.println("这是一个季节");
//	}
}

/*
* 注解
* 1.JDK提供的常用的注解
*  @Override: 限定重写父类方法, 该注释只能用于方法
@Deprecated: 用于表示某个程序元素(类, 方法等)已过时
@SuppressWarnings: 抑制编译器警告
2.如何自定义一个注解
3.元注解

*/
public class TestAnnotation {
public static void main(String[] args) {
Person p = new Student();
p.walk();
p.eat();

@SuppressWarnings({ "rawtypes", "unused" })
List list = new ArrayList();

@SuppressWarnings("unused")
int i = 10;
//		System.out.println(i);
}
}
@MyAnnotation(value = "atguigu")
class Student extends Person{
@Override
public void walk(){
System.out.println("学生走路");
}
@Override
public void eat(){
System.out.println("学生吃饭");
}
}
@Deprecated
class Person{
String name;
int age;

public Person() {
super();
}
@MyAnnotation(value = "atguigu")
public Person(String name, int age) {
super();
this.name = name;
this.age = age;
}
@MyAnnotation(value = "atguigu")
public void walk(){
System.out.println("走路");
}
@Deprecated
public void eat(){
System.out.println("吃饭");
}
@Override
public String toString() {
return "Person [name=" + name + ", age=" + age + "]";
}

}

//自定义的注解
@Target({TYPE,FIELD, METHOD, PARAMETER, CONSTRUCTOR, LOCAL_VARIABLE})
@Retention(RetentionPolicy.RUNTIME)
public @interface MyAnnotation {
String value() default "hello";
}