switch语句case使用枚举：应用_switch case 枚举类型

例一：

    public static enum WeChatRecordMsgType {
        EVENT("event"),
        TEXT("text"),
        IMAGE("image"),
        VOICE("voice"),
        VIDEO("video");
        private final String msgType;

        WeChatRecordMsgType(String msgType) {
            this.msgType = msgType;
        }

        public static WeChatRecordMsgType msgTypeValueOf(String msgType) {
            switch (msgType) {
                case "event":
                    return EVENT;
                case "text":
                    return TEXT;
                case "image":
                    return IMAGE;
                case "voice":
                    return VOICE;
                case "video":
                    return VIDEO;
                default:
                    return null;
            }
        }
    }
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类中调用：

  final WeChatRecordMsgType type = WeChatRecordMsgType.msgTypeValueOf(inMessage.getMsgType());
  switch (type) {
        case EVENT:
            content = inMessage.getEventKey();
            break;
        case TEXT:
            content = inMessage.getContent();
            break;
        case VOICE:
        case VIDEO:
        case IMAGE:
            content = inMessage.getMediaId();
            break;
        default:
             throw new WrongCodeError("type字段有误:" + type);
    }
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例二

 public enum HomeworkType {

        PreviewBeforeClass(2, "课前导学"), HomeworkAfterClass(1, "课后作业");

        private final int type;
        private final String meaning;

        private HomeworkType(int type, String meaning) {
            this.type = type;
            this.meaning = meaning;
        }

        public static HomeworkType valueOf(int type) {
            switch (type) {
            case 1:
                return HomeworkAfterClass;
            case 2:
                return PreviewBeforeClass;
            default:
                return null;
            }
        }
    }
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枚举的使用：初始化，构造函数，避免空指针

 public enum APPType {
        WYS_STUDENT, 
        WYS_TEACHER, 
        RJS_STUDENT,
        QT;// 其他

 static public APPType fromString(String type) {	//格式化枚举类
            if (type != null) {
                try {
                    return APPType.valueOf(type.trim().toUpperCase());
                } catch (IllegalArgumentException ex) {
                }
            }
            return APPType.QT;
        }

 public static APPType getValidAppType(APPType appType) { //使用枚举前，调用：反初始值
            if (null == appType) {
                return WYS_STUDENT;
            }
            switch (appType) {
            case WYS_STUDENT:
            case WYS_TEACHER:
                return WYS_STUDENT;
            case RJS_STUDENT:
            case RJS_TEACHER:
                return RJS_STUDENT;
            default:
                return appType;
            }
        }

}
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