Java中枚举的使用

Java中枚举其实就是静态常量，今天发现枚举里面其实还能加方法，学习了下，

代码如下：

 package org.pine.test;

 import java.util.HashMap;
 import java.util.Map;

 public enum Color {
     //静态常量
     RED(1,"红色"),GREEN(2,"绿色"),BLUE(3,"蓝色"),YELLOW(7,"黄色");
     //属性
     private int index;
     private String name;
     //构造方法
     Color(int index, String name){
        this.index=index;
        this.name=name;
     }
     //set、get
     public int getIndex() {
         return this.index;
     }

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

     public String getName() {
         return this.name;
     }

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

     /**
      *通过index获取name
      * @param index
      * @return name
      */
     public static String getName(int index){
         Color[] colors = Color.values();
         for(Color color:colors){
            if(color.getIndex()==index){
              return color.getName();
            }
         }
         throw new RuntimeException("Could not find the Color.");
     }

     /**
      * 通过name获取index
      * @param name
      * @return index
      */
     public static int getIndex(String name){
         Color[] colors = Color.values();
         for(Color color:colors){
             if(color.getName().equals(name)){
                 return color.getIndex();
             }
         }
         throw new RuntimeException("Could not find the Color.");
     }

     /**
      *通过index获取Color
      * @param index
      * @return Color
      */
     public static Color getColor(int index){
         Color[] colors = Color.values();
         for(Color color:colors){
             if(color.getIndex()==index){
                 return color;
             }
         }
         throw new RuntimeException("Could not find the Color.");
     }

     /**
      * 通过name获取Color
      * @param name
      * @return Color
      */
     public static Color getColor(String name){
         Color[] colors = Color.values();
         for(Color color:colors){
             if(color.getName().equals(name)){
                 return color;
             }
         }
         throw new RuntimeException("Could not find the Color.");
     }

     /**
      * 红路灯变换
      */
     public static Color next(Color color){
         Map<Color,Color> map = new HashMap();
         map.put(RED,GREEN);
         map.put(GREEN,YELLOW);
         map.put(YELLOW,RED);
         return map.get(color);
     }

     /**
      * 重写toString
      * @return
      */
     @Override
     public String toString() {
         return "Color{" +
                 "index=" + index +
                 ", name='" + name + '\'' +
                 '}';
     }
 }

测试类：

 package org.pine.test;

 public class ColorTest {

    public static void main(String[] args){
        Color r = Color.RED;
        r.setIndex(4);

        Color g = Color.GREEN;
        g.setIndex(5);

        Color b= Color.BLUE;
        b.setIndex(6);

        System.out.println(r.getIndex());
        System.out.println(g.getIndex());
        System.out.println(b.getIndex());

        System.out.println(r);
        System.out.println(g);
        System.out.println(b);

        //通过index获取name
        String name = Color.getName(4);
        System.out.println(name);

        //通过name获取index
        int index = Color.getIndex("绿色");
        System.out.println(index);

        //通过index获取Color
        Color c1 = Color.getColor(5);
        System.out.println(c1);

        //通过name获取Color
        Color c2 = Color.getColor("蓝色");
        System.out.println(c2);

        Color c3 = Color.valueOf("RED");
        System.out.println(c3);
        //红绿灯变换
        System.out.println(Color.next(Color.RED));
        System.out.println(Color.next(Color.GREEN));
        System.out.println(Color.next(Color.YELLOW));
    }
 }