相关疑难解决方法(0)

为什么enum的构造函数不能访问静态字段和方法？这对于类非常有效,但不允许使用枚举.

我要做的是将我的枚举实例存储在静态Map中.考虑这个允许通过abbreivation查找的示例代码:

public enum Day {
    Sunday("Sun"), Monday("Mon"), Tuesday("Tue"), Wednesday("Wed"), Thursday("Thu"), Friday("Fri"), Saturday("Sat");

    private final String abbreviation;

    private static final Map<String, Day> ABBREV_MAP = new HashMap<String, Day>();

    private Day(String abbreviation) {
        this.abbreviation = abbreviation;
        ABBREV_MAP.put(abbreviation, this);  // Not valid
    }

    public String getAbbreviation() {
        return abbreviation;
    }

    public static Day getByAbbreviation(String abbreviation) {
        return ABBREV_MAP.get(abbreviation);
    }
}

这不起作用,因为枚举不允许在其构造函数中使用静态引用.然而,如果实现为类,它只能找到:

public static final Day SUNDAY = new Day("Sunday", "Sun");
private Day(String name, String abbreviation) {
    this.name = name;
    this.abbreviation = abbreviation;
    ABBREV_MAP.put(abbreviation, …

我有一个Java Enum:

public enum CodeType {
  BRONZE("00001BP", "BAP"),
  SILVER("00002SL", "SAP"),
  GOLD("00003GL", "GAP"),
  MOBILE("00004MB", "TCM"),
  SOCIAL("00005SM", "ASM"),
  WEB_PRESENCE("00006WP", "GLO"),
  EMAIL_MARKETING("00007EM", "PEM"),
  CUSTOM_DIAMOND("00008CD", "PCS"),
  CONSUMER_PORTAL("00009CP", "CPS");

  private String code;
  private String key;

  CodeType(String code, String key) {
    this.code = code;
    this.key = key;
  }

  ...
}

如你所见,我有九个元素,每个元素都有两个值.我的问题是如何从属性或xml等文件中加载这些元素的值？我的意思是:

BRONZE(isLoadedFromFile, isLoadedFromFile),
...
CONSUMER_PORTAL(isLoadedFromFile, isLoadedFromFile);

非常感谢.