JsonGenerator write object and string field

Question

I'm trying to generate a JSON string from an object and adding a field on the same level.

{
    "objField1": "objValue1",
    "objField2": "objValue2",
    "stringField": "stringValue"
}

Here's the code snippet:

PrintWriter writer = response.getWriter();
ObjectMapper mapper = new ObjectMapper();
JsonGenerator generator = mapper.getJsonFactory().createJsonGenerator(writer).useDefaultPrettyPrinter();
// mapper.writeValue(generator, responseObj); // tried this without success instead of the following
generator.writeObject(obj);
generator.writeStringField("stringField", "stringValue");
generator.close();
writer.close();

But all I get are the fields from my object:

{
    "objField1": "objValue1",
    "objField2": "objValue2"
}

JSONObject inner1 = new JSONObject(); inner1.put("string", "string value"); you can try like this. — Kumaresan Perumal, Oct 28 '15 at 13:30
How to set it on the generator then? `generator.writeObject(inner1);`? That didn't work. Same result. — dtrunk, Oct 28 '15 at 13:33
i did not understand your question. please tell me. how do you want? — Kumaresan Perumal, Oct 28 '15 at 13:40
The first code block is what I want. The last is what I get. And the second is the code itself. — dtrunk, Oct 28 '15 at 13:42

score 2 · Accepted Answer · edited May 23 '17 at 10:27

2

public void serialize(Object bean, JsonGenerator jgen,
                SerializerProvider provider) throws IOException,
                JsonGenerationException {           
            jgen.writeStartObject();                        
            serializeFields(bean, jgen, provider);
            jgen.writeStringField("extraField", "extraFieldValue"); 
            jgen.writeEndObject();
        }

look at this link: Jackson: How to add custom property to the JSON without modifying the POJO

edited May 23 '17 at 10:27

Community

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answered Oct 28 '15 at 14:08

Kumaresan Perumal

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Where does `serializeFields` come from? – Kalle Richter Mar 10 '18 at 12:40
1

It's not a great answer. It's from BeanSerializerBase, which cannot be constructed with @JsonSerializer, as it has no default constructor – Henrik Vendelbo Sep 24 '18 at 15:56

JsonGenerator write object and string field

1 Answers1