java - 使用 ObjectReader 相对于 ObjectMapper 有什么好处？

Question

如何使用 ObjectReader(ObjectReader 的单个实例)重构以下代码

private MessageStructure parseSQSMessageToMessageStructure(final String queueMessage)
    throws IOException, ObjectMapperException {

    JsonNode messageAsJSON = objectMapper.readTree(queueMessage);
    JsonNode messageAsJSONKey = messageAsJSON.get(MESSAGE_JSON_KEY);
    return objectMapper.readValue(messageAsJSONKey.textValue(), MessageStructure.class);
}

Answer 1

正如@shmosel所说，您的问题与标题不符。

如果您希望将 ObjectMapper 实例替换为 ObjectReader，请替换以下行。

来自:

return objectMapper.readValue(messageAsJSONKey.textValue(), MessageStructure.class);

future :

return objectReader.readValue(messageAsJSONKey.textValue(), MessageStructure.class);

上面的代码片段假设 objectReader 是 ObjectReader 类的实例。

下面是我从 ObjectReader 的 JavaDocs 获得的有关其性能的信息。

Uses "mutant factory" pattern so that instances are immutable (and thus fully thread-safe with no external synchronization); new instances are constructed for different configurations. Instances are initially constructed by {@link ObjectMapper} and can be reused, shared, cached; both because of thread-safety and because instances are relatively light-weight.

希望这有帮助!