java 枚举类(简单使用)

直接上代码

用法一(常量):

package com.ou.test;

import com.sun.corba.se.impl.util.SUNVMCID;

public class Enum {
    public static void main(String[] args) {
        Weekday day = Weekday.FIVE;
        System.out.println(day);//直接输出FIVE
    }
}

enum Weekday{
    ONE,TWO,THREE,FOUR,FIVE,SIX,SEVEN;
}

结果:

看起来和上面的静态变量使用方式差不多,而且默认的toString方法返回的就是对应的名字。

用法二(switch):

 

package com.ou.test;
public class Enum {
public static void main(String[] args) {
Color color = Color.GREEN;
switch (color){
case RED:
color = Color.GREEN;
break;
case YELLOW:
color = Color.RED;
break;
case GREEN:
color = Color.YELLOW;
break;
}
System.out.println(color);
}

}
enum Color{
GREEN, YELLOW, RED
}

 结果:

 

用法三:向枚举中添加新方法

package com.ou.test;
public class Enum {
public static void main(String[] args) {
System.out.println(Color.getName(3));
System.out.println(Color.getIndex("绿色"));
}

}
enum Color{
RED("红色", 1), GREEN("绿色", 2), BLANK("白色", 3), YELLO("黄色", 4);
//成员变量
private String name;
private int index;
//构造方法
Color(String name, int index) {
this.name=name;
this.index=index;
}
//普通的方法 (根据索引号来找值)
public static String getName(int index){
for (Color c:Color.values()){
if (c.getIndex() == index){
return c.name;
}
}
return null;
}
//普通的方法 (根据值来找索引号)
public static int getIndex(String name){
for (Color c:Color.values()) {
if (c.getName()==name){
return c.index;
}
}
return -1;
}
//get set
public String getName() {
return name;
}

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

public int getIndex() {
return index;
}

public void setIndex(int index) {
this.index = index;
}
}

结果:

 

 

 

posted @ 2018-08-14 19:59  追梦滴小蜗牛  阅读(1503)  评论(0编辑  收藏  举报