Map JSON array of objects to @RequestBody List using jackson

Question

I\'m having issues using Jackson to map a Javascript posted JSON array of hashes (Tag).

Here is the data received by the controller @RequestBody (It is send wit

Answer 1

Another way to do this is to rather obtain an array than a List, as follows:

@RequestBody Tag[] entities

Answer 2

Jackson requires a default constructor with no parameters on custom Objects, so you'll need to simply add a default constructor to your Tag class.

In your case simply add to your Tag class:

public Tag(){}

Answer 3

It sounds like Spring is not passing full type information for some reason, but rather a type-erased version, as if declaration was something like List<?> tag. I don't know what can be done to fully resolve this (may need something from Spring integration team), but one work-around is to define your own type like:

static class TagList extends ArrayList<Tag> { }

and use that instead. This will retain generic parameterization through super-type declarations so that even if Spring only passes equivalent of TagList.class, Jackson can figure out the Tag parameter.