一文秒懂Java enum常见的用法讲解

public enum WeekDay {
  SUN, MON, TUE, WED, THT, FRI, SAT
}

public enum WeekDay {
  SUN, MON, TUE, WED, THT, FRI, SAT
}
 
public class SelectDay{
  WeekDay weekday = WeekDay.SUN;
  public void select(){
    switch(weekday){
      case SUN:
        weekday = WeekDay.SUN;
        break;
      ...
    }
  }
}

public 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 
  private Color(String name, int index) { 
    this.name = name; 
    this.index = index; 
  } 
  // 普通方法 
  public static String getName(int index) { 
    for (Color c : Color.values()) { 
      if (c.getIndex() == index) { 
        return c.name; 
      } 
    } 
    return null; 
  } 
  // get set 方法 
  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; 
  } 
} 

public 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 
  private Color(String name, int index) { 
    this.name = name; this.index = index; 
  } 
  //覆盖方法 
  @Override 
  public String toString() { 
  return this.index+"_"+this.name; 
  } 
}

public interface Behaviour { 
  void print(); 
  String getInfo(); 
} 
public enum Color implements Behaviour{ 
  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 
  private Color(String name, int index) { 
    this.name = name; this.index = index; 
  } 
  //接口方法 
  @Override 
  public String getInfo() { 
    return this.name; 
  } 
  //接口方法 
  @Override 
  public void print() { 
    System.out.println(this.index+":"+this.name); 
  } 
}

public interface Food { 
  enum Coffee implements Food{ 
    BLACK_COFFEE,DECAF_COFFEE,LATTE,CAPPUCCINO 
  } 
  enum Dessert implements Food{ 
    FRUIT, CAKE, GELATO 
  } 
}

public class Test {
  public static void main(String[] args) {
    EnumSet<WeekDay> week = EnumSet.noneOf(WeekDay.class);
    week.add(WeekDay.MON);
    System.out.println("EnumSet中的元素：" + week);
    week.remove(WeekDay.MON);
    System.out.println("EnumSet中的元素：" + week);
    week.addAll(EnumSet.complementOf(week));
    System.out.println("EnumSet中的元素：" + week);
    week.removeAll(EnumSet.range(WeekDay.FRI, WeekDay.SAT));
    System.out.println("EnumSet中的元素：" + week);
  }