Question

我有一个带有重复键的JSON，如下所示。

    {
        "name": "Test",
        "attributes": [{
            "attributeName": "One",
            "attributeName": "Two",
            "attributeName": "Three"
        }]
    }

当我使用杰克逊将其转换为Map<String, Object>时，它会如下所示进行转换。

{name = Test，attributes = [{attributeName = Three}]}

考虑最后一次出现的属性名称的值。有没有办法告诉杰克逊将其表示为Multimap？我可以使用Multimap的任何实现。我目前的代码如下所示：

import java.util.HashMap;
import java.util.Map;

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;

public class TestJSON {

    public static void main(String[] args) throws Exception{
        ObjectMapper mapper = new ObjectMapper();
        String json = "{\"name\": \"Test\",\"attributes\": [{\"attributeName\": \"One\",\"attributeName\": \"Two\",\"attributeName\": \"Three\"}]}";
        Map<String, Object> map = new HashMap<>();
        map = mapper.readValue(json, new TypeReference<Map<String, Object>>(){});
        System.out.println(map);
    }

}

Answer 1

不要认为Jackson会以他的本地方式处理它，但是你可以将这个JSON包装成简单的POJO并从中获取Multimap。例如：

public class Attribute {
    private String attributeName;

    // getter and setter here
}

public class AttributeContainer {
    private String name;
    private List<Attribute> attributes;

    public Multimap<String, String> getAttributeMultiMap() {
      ImmutableMultimap.Builder<String, String> builder = ImmutableMultimap.builder();
          for (Attribute attribute : attributes) {
             builder.put("attributeName", attribute.getAttributeName())
          }
       return builder.build();
    }

    // getters and setters here
}

public void main(String[] args) {
    ObjectMapper mapper = new ObjectMapper();
    String json = "{\"name\": \"Test\",\"attributes\": [{\"attributeName\": \"One\",\"attributeName\": \"Two\",\"attributeName\": \"Three\"}]}";
    AttributeContainer attributeContainer;
    attributeContainer = mapper.readValue(json, new TypeReference<AttributeContainer>(){});

    System.out.println(attributeContainer.getAttributeMultiMap());
}

使用重复键将JSON表示为Multimap

1 个答案: