Is there a way to easily upade a JSON node using Jackson's ObjectMapper?-CodePudding

Given this JSON read from a file:

{
    "Book": "Test",
    "Subscription": [{
        "RateIt": [{
            "Id": "1234",
            "Size": "XL",
            "RateMe": [{
                "id": "5678",
                "Pages": ""
            }],
            "Test_Demo": null
        }],
        "DemoID": "test1111",
        "subNumber": "9999"

    }],
    "Author_FirstName": "Test"
}

I tried to update DemoID field with a different value, this way:

ObjectMapper mapper = new ObjectMapper();
JsonNode requestParams = mapper.readTree(new File("src/test/resources/myFile.json"));
JsonNode subscriptionPath = requestParams.at("/Subscription");
System.out.println(subscriptionPath ); //value was retrieved OK
((ObjectNode) subscriptionPath).put("DemoID", "test0000"); //error on this line

But got the exception:

java.lang.ClassCastException: com.fasterxml.jackson.databind.node.TextNode cannot be cast to com.fasterxml.jackson.databind.node.ObjectNode

I also tried using the DemoIDpath instead, but got the same exception:

JsonNode idPath = requestParams.at("/Subscription/0/DemoID");//path was found OK
((ObjectNode) idPath).put("DemoID", "test0000"); // error on this line

What am I doing wrong with the use of ObjectNode?

CodePudding user response：

Subscription is an array. You may see it better with proper formatting:

{
    "Book": "Test",
    "Subscription": [
        {
            "RateIt": [
                {
                    "Id": "1234",
                    "Size": "XL",
                    "RateMe": [
                        {
                            "id": "5678",
                            "Pages": ""
                        }
                    ],
                    "Test_Demo": null
                }
            ],
            "DemoID": "test1111",
            "subNumber": "9999"
        }
    ],
    "Author_FirstName": "Test"
}

Change code to:

 ((ObjectNode) subscriptionPath.get(0)).put("DemoID", "test0000");