How to modify JsonNode in Java?

By | July 4, 2019

Question

I need to change a JSON attribute’s value in Java, I can get the value properly but I couldn’t modify the JSON.

here is the code below

  JsonNode blablas = mapper.readTree(parser).get("blablas");
    for (JsonNode jsonNode : blablas) {
        String elementId = jsonNode.get("element").asText();
        String value = jsonNode.get("value").asText();
        if (StringUtils.equalsIgnoreCase(elementId, "blabla")) {
            if(value != null && value.equals("YES")){
                 // I need to change the node to NO then save it into the JSON
            }
        }
    }

What is the best way to do this?

Solution

JsonNode is immutable and is intended for parse operation. However, it can be cast into ObjectNode (and ArrayNode) that allow mutations:

((ObjectNode)jsonNode).put("value", "NO");

For an array, you can use:

((ObjectNode)jsonNode).putArray("arrayName").add(object.ge‌​tValue());

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