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javajsonpjackson

Deserialize JSONP with Jackson

For some reason Jackson 2.3.0 is unable to parse a JSONP response.

com.fasterxml.jackson.core.JsonParseException: Unrecognized token 'my_json_callback':

I've got the deserialization process to work without the callback.

I've tried with the Jackson JAX-RS package which includes a @JSONP annotation, but this seems to be used only when serializing.

Solution

  • Finally I've been able to remove the callback part of the JSONP response.

    First, Jackson is able to parse the JSON even when it ends with a parenthesis. So, by simply removing the my_json_callback( from the response is enough.

    Since I'm using Apache's HTTP Client, this fixes the issue:

    String callback = "my_json_callback(";
InputStreamReader r = new InputStreamReader(response.getEntity().getContent());
r.skip(callback.length());
return mapper.readValue(r, MyObject.class);

    The idea is not having to convert the Reader to a String and then parsing that String after removing the callback part.

    I was also able to accomplish the same results using JSONTokener from json.org library for a given JSONP String:

    JSONTokener t = new JSONTokener(json);
t.nextValue(); // skip the callback
return mapper.readValue(t.nextValue().toString(), MyObject.class);