有没有办法使用 Jackson ObjectMapper 轻松更新 JSON 节点？

Question

鉴于此 JSON 从文件中读取：

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

    }],
    "Author_FirstName": "Test"
}

我尝试用不同的值更新 DemoID 字段，这样：

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

但是遇到异常：

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

我也尝试使用 DemoIDpath，但遇到了同样的异常：

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

我在使用 ObjectNode 时做错了什么？

Answer 1

Subscription 是一个数组。如果格式正确，您可能会看得更清楚：

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

将代码更改为：

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

有没有办法使用 Jackson ObjectMapper 轻松更新 JSON 节点？

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

java

json

jackson

objectmapper