使用Jackson ObjectMapper反序列化或序列化任何类型的对象并处理异常 [英] Deserializing or serializing any type of object using Jackson ObjectMapper and handling exceptions

问题描述

我目前正在尝试重构此代码，以允许更多可能的类类型（用伪代码简化，但要旨相同）：

I currently have this code I am trying to refactor in order to allow for more possible class types (simplified with dummy code, but the gist is the same):

private String serializeSomething(final SomeSpecificClass something) {
    try {
        return mapper.writeValueAsString(someething);
    } catch (final IOException e) {
        throw new SomeCustomException("blah", e);
    }
}

private SomeSpecificClass deserializeSomething(final String payload) {
    try {
        return mapper.readValue(payload, SomeSpecificClass.class);
    } catch (final IOException e) {
        // do special things here
        throw new SomeCustomException("blah", e);
    }
}

我们最近发现我们可能不得不接受其他类型，而不仅仅是 SomeSpecificClass 。有没有一种更好的方法，而不必将所有内容都更改为 Object 而不是 SomeSpecificClass ？这样我们就可以在 deserializeSomething 中返回正确的类型（而不必在从调用者那里获得返回值后强制转换它）？

We recently found out that we will probably have to accept other types here, not just SomeSpecificClass. Is there a better way of doing this without having to change everything to Object instead of SomeSpecificClass? So that we can return the right type in deserializeSomething (and not have to cast it after we get the return value from the caller)?

推荐答案

从示例实现开始：

class JsonObjectConverter {

    private ObjectMapper mapper = new ObjectMapper();

    public String serialiseToJson(Object value) {
        try {
            return mapper.writeValueAsString(value);
        } catch (JsonProcessingException e) {
            throw new IllegalArgumentException("Could not serialise: " + value, e);
        }
    }

    public <T> T deserialiseFromJson(String json, Class<T> clazz) {
        try {
            return mapper.readValue(json, clazz);
        } catch (IOException e) {
            throw new IllegalArgumentException("Could not deserialize: " + clazz, e);
        }
    }

    public SomeSpecificClass deserialiseToSomeSpecificClass(String json) {
        return deserialiseFromJson(json, SomeSpecificClass.class);
    }
}

您可以编写两种常规方法： serialiseToJson 和 deserialiseFromJson 可以将任何类型序列化为 JSON 并反序列化 JSON 有效负载到给定的 Class 。当然，您可以为最常见和最常用的类实现一些额外的方法，例如 deserialiseToSomeSpecificClass 。您可以使用以下格式编写任意数量的方法： deserialiseToXYZ 。

You can write two general methods: serialiseToJson and deserialiseFromJson which can serialise any type to JSON and deserialise JSON payload to given Class. You can implement of course some extra methods for most common and most used classes like deserialiseToSomeSpecificClass. You can write as many method as you need in this format: deserialiseToXYZ.

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