Java 枚举

最新推荐文章于 2025-09-09 09:10:31 发布

转载最新推荐文章于 2025-09-09 09:10:31 发布 · 44 阅读

0 ·

CC 4.0 BY-SA版权

原文链接：http://www.cnblogs.com/MrTanJunCai/p/9906855.html

文章标签：

#java

本文深入探讨了枚举类型的使用场景，特别是在Java中如何通过枚举实现单例模式，以及从JDK5.0开始，枚举类的简化创建方式。通过实例展示了手工创建枚举的复杂过程，并对比了使用枚举类的简洁性。文章还介绍了如何定义带有属性的枚举，为读者提供了全面的枚举类型理解。

*************************枚举 *************************************

JDK5.0的特性

一.为什么使用枚举

单例: 是为了保证一个类只有一个唯一的实例

枚举: 当一个类的对象个数固定的时候推荐使用枚举

例如: 季节类、性别类、星期类

***********************手工创建枚举*****************************

package com.chapter18.枚举;

//手工创建枚举
public class Season {

private String name;
private String desc;

public static final Season SPRING = new Season("春天","趁春踏青");
public static final Season SUMMER = new Season("夏天","烈日炎炎");
public static final Season FALL = new Season("秋天","秋高气爽");
public static final Season WINTER = new Season("冬天","围炉赏雪");

//1.构造函数私有
private Season(){

}

private Season(String name, String desc) {
super();
this.name = name;
this.desc = desc;
}

//2.提供一个静态方法创建4个对象的其中一个
public static Season getSeason(int sum){

switch(sum){
case 1:return SPRING;
case 2:return SUMMER;
case 3:return FALL;
case 4:return WINTER;
default:return null;
}

}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public String getDesc() {
return desc;
}

public void setDesc(String desc) {
this.desc = desc;
}

@Override
public String toString() {
return "Season [name=" + name + ", desc=" + desc + "]";
}

public static void main(String[] args) {

//1. 类名.对象名
System.out.println(Season.FALL);

//2. 类名.getSeason()方法获得对象
Season season = Season.getSeason(3);
System.out.println(season.getName() + "这真是一个" + season.getDesc() + "的季节!");
}

}

程序员自己手工创建枚举比较麻烦, 从JDK5.0开始, 有了枚举类..简化了枚举的编写

***********************************定义枚举**********************************************

package com.chapter18;

//定义一个枚举
public enum Season {

SPRING,SUMMER,FALL,WINTER;

public static void main(String[] args) {

Season season = Season.FALL;
//System.out.println(season);

Season[] seasonArr = Season.values();

for(Season s:seasonArr){
System.out.println(s);
}
}
}

***********************************定义带属性的枚举****************************************
package com.chapter18;

//定义一个枚举
public enum Season {

SPRING("春天","趁春踏青"),SUMMER("夏天","烈日炎炎"),FALL("秋天","秋高气爽"),WINTER("冬天","围炉赏雪");

private String name;
private String desc;

private Season(String name,String desc){
this.name = name;
this.desc = desc;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public String getDesc() {
return desc;
}

public void setDesc(String desc) {
this.desc = desc;
}

public static void main(String[] args) {

Season season = Season.FALL;
//System.out.println(season);

Season[] seasonArr = Season.values();

for(Season s:seasonArr){
System.out.println(s.getName() + "这真是一个" + s.getDesc());
}
}
}

转载于:https://www.cnblogs.com/MrTanJunCai/p/9906855.html