如何将JSON值数组转换为Java对象

Question

我试图将下面的Json数组转换为特定的Java对象。

[
    {
        "Dummy": {
            "attr": "PRIMITIVE",
            "value": {
                "Initial": "M",
                "Name": "Potato"
            }
        }
    },
    {
        "Dummy": {
            "attr": "PRIMITIVE",
            "value": {
                "Initial": "A",
                "Name": "Potatoo1"
            }
        }
    }
]

编辑：更新了正确的JSON结构

下面是我目前使用的对象映射器：

     ObjectMapper mapper = new ObjectMapper();
        Dummy[] myObjects = mapper.readValue(resultStr, Dummy[].class);
    
public class Dummy{

    public String attr;
    public value val;
}

public class value {

    public String Initial;
    public String Name;
}

然而，我在尝试反序列化com时出错。fasterxml。杰克逊。数据绑定。exc.MismatchedInputException:无法反序列化com类型的值。实例演示。虚拟来自数组值

Answer 1

您的输入没有有效的JSON数据，请使用JSON格式化程序/验证程序进行检查（例如https://jsonformatter.curiousconcept.com)

我假设，您的数据的“正确”JSON如下所示：

[
    {
        "Dummy": {
            "attr": "PRIMITIVE",
            "value": {
                "Initial": "M",
                "Name": "Potato"
            }
        }
    },
    {
        "Dummy": {
            "attr": "PRIMITIVE",
            "value": {
                "Initial": "A",
                "Name": "Potatoo1"
            }
        }
    }
]

这个JSON可以像这样映射：

import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;


public class OMTest {

    public void deserialize() throws JsonMappingException, JsonProcessingException {
        String json = "[{\"Dummy\": {\"attr\": \"PRIMITIVE\",\"value\": {\"Initial\": \"M\",\"Name\": \"Potato\"}}},{\"Dummy\": {\"attr\": \"PRIMITIVE\",\"value\": {\"Initial\": \"A\",    \"Name\": \"Potatoo1\"}}}]";

        ObjectMapper mapper = new ObjectMapper();
        YourClass[] myObjects = mapper.readValue(json, YourClass[].class);

        // do something...
        System.out.println(myObjects.length);
    }

    private static class YourClass {
        @JsonProperty("Dummy")
        public Dummy dummy;
    }

    private static class Dummy {
        public String attr;
        public Value value;
    }

    private static class Value {
        @JsonProperty("Initial")
        public String initial;
        @JsonProperty("Name")
        public String name;
    }
}