• Skip to main content
  • Skip to primary sidebar
  • Skip to footer
  • About
  • Life
  • Tech
  • Travel
  • Work
  • Questions
  • Contact

Welcome

.

Jackson Deserialize List Generically

April 11, 2020 by

Questions › Jackson Deserialize List Generically
0
Vote Up
Vote Down
Garmaine asked 3 years ago

I've been using Jackson to serialize/deserialize objects for years and have always found it needlessly complicated to use TypeReference<T> to deserialize List etc. I created a simple helper function:

public static <T> TypeReference<List<T>> list() {
    return new TypeReference<List<T>>(){}
}

With intended use:

List<Foo> foos = objectMapper.readValue(json, list());

And it works! Kind of. When inspecting through the debugger, rather than a list of Foo, it is rather a list of LinkedHashMap. I understand that ObjectMapper deserializes into LinkedHashMap for type Object and I read the explanation for that here:

Jackson and generic type reference

However, why is it able to assign List<LinkedHasMap> to a List<Foo>? At the very least shouldn't that be some sort of ClassCastException?

Also, is there anyway to do this with Java's type system?

NOTE: the following method declaration has the same issue, which makes sense because the additional argument is not needed for T to be determined:

public static <T> TypeReference<List<T>> listOf(Class<T> ignored) {
    return new TypeReference<List<T>>(){}
}
Are you looking for the answer?
Original Question and Possible Answers can be found on `http://stackoverflow.com`

Question Tags: jackson, java

Please login or Register to submit your answer




Primary Sidebar

Tags

Advancements architecture beautiful life best building calling city commercial convenience employment Finances Cognitive decline Future gadgets Hidden Gems highway Home houses hydration Impact Innovations lamp lighting Mental health military tech Must-See New York City occupation Productivity recreation romance sepia shopping sippy cups smartphones social Technological breakthroughs technology toddlers Treasures turns Uncover Well-being Wonders Work Young onset dementia

Newsletter

Complete the form below, and we'll send you all the latest news.

Footer

Footer Funnies

Who knew that reading the footer could be such a hilarious adventure? As we navigate websites, books, and documents, we often stumble upon the unassuming space at the bottom, only to discover a treasure trove of amusement. In this side-splitting compilation, we present 100 jokes that celebrate the unsung hero of content – the footer. Get ready to chuckle, giggle, and maybe even snort as we dive into the world of footnotes, disclaimers, and hidden comedic gems. Brace yourself for a wild ride through the footer!

Recent

  • Unveiling the Enigma: Almost-Magical Lamp Lights Highway Turns
  • The Impact of Young Onset Dementia on Employment and Finances: Optimizing Post-Diagnostic Approaches
  • 11 Wonders of 2023 Technological Breakthrough – Unveiling the Future
  • Work from Home and Stay Mentally Sane – Achieve Productivity and Well-being
  • Hidden Gems of New York City – Uncover the Must-See Treasures!

Search

Tags

Advancements architecture beautiful life best building calling city commercial convenience employment Finances Cognitive decline Future gadgets Hidden Gems highway Home houses hydration Impact Innovations lamp lighting Mental health military tech Must-See New York City occupation Productivity recreation romance sepia shopping sippy cups smartphones social Technological breakthroughs technology toddlers Treasures turns Uncover Well-being Wonders Work Young onset dementia

Copyright © 2023