Jackson enum Serializing 和 DeSerializer [英] Jackson enum Serializing and DeSerializer

问题描述

我使用的是 JAVA 1.6 和 Jackson 1.9.9 我有一个枚举

I'm using JAVA 1.6 and Jackson 1.9.9 I've got an enum

public enum Event {
    FORGOT_PASSWORD("forgot password");

    private final String value;

    private Event(final String description) {
        this.value = description;
    }

    @JsonValue
    final String value() {
        return this.value;
    }
}

我添加了一个@JsonValue，这似乎完成了将对象序列化为的工作:

I've added a @JsonValue, this seems to do the job it serializes the object into:

{"event":"forgot password"}

但是当我尝试反序列化时，我得到了一个

but when I try to deserialize I get a

Caused by: org.codehaus.jackson.map.JsonMappingException: Can not construct instance of com.globalrelay.gas.appsjson.authportal.Event from String value 'forgot password': value not one of declared Enum instance names

我在这里遗漏了什么?

推荐答案

@xbakesx 指出的序列化/反序列化解决方案如果您希望将 enum 类与其 JSON 表示完全分离， 是一个很好的选择.

The serializer / deserializer solution pointed out by @xbakesx is an excellent one if you wish to completely decouple your enum class from its JSON representation.

或者，如果您更喜欢独立的解决方案，基于 @JsonCreator 和 @JsonValue 注释的实现会更方便.

Alternatively, if you prefer a self-contained solution, an implementation based on @JsonCreator and @JsonValue annotations would be more convenient.

因此利用 @Stanley 的示例，以下是一个完整的自包含解决方案(Java 6，Jackson 1.9):

So leveraging on the example by @Stanley the following is a complete self-contained solution (Java 6, Jackson 1.9):

public enum DeviceScheduleFormat {

    Weekday,
    EvenOdd,
    Interval;

    private static Map<String, DeviceScheduleFormat> namesMap = new HashMap<String, DeviceScheduleFormat>(3);

    static {
        namesMap.put("weekday", Weekday);
        namesMap.put("even-odd", EvenOdd);
        namesMap.put("interval", Interval);
    }

    @JsonCreator
    public static DeviceScheduleFormat forValue(String value) {
        return namesMap.get(StringUtils.lowerCase(value));
    }

    @JsonValue
    public String toValue() {
        for (Entry<String, DeviceScheduleFormat> entry : namesMap.entrySet()) {
            if (entry.getValue() == this)
                return entry.getKey();
        }

        return null; // or fail
    }
}

这篇关于Jackson enum Serializing 和 DeSerializer的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！