库类的 JSON snake case

Question

我有一个类正在扩展一些库类。如何将类属性扩展为驼峰式大小写。@JsonNaming(PropertyNamingStrategy.SnakeCaseStrategy.class)class Test extends Abc {}// Library class which I can't modifyclass Abc {  private firstName; }如何将firstName设为first_name

Answer 1

你可以使用 mixin 。基本上，您在另一个类上定义注释，然后将真实类与 objectMapper 中的 mixin 相关联

public class JacksonMixin {

    @JsonAutoDetect(fieldVisibility = JsonAutoDetect.Visibility.ANY)

    @JsonNaming(PropertyNamingStrategy.SnakeCaseStrategy.class)

    abstract class MixinAbc{}

    // Library class which I can't modify

    class Abc {

      private String firstName;

     }

    @Test

    public void testMixin() throws JsonProcessingException {

        ObjectMapper objectMapper = new ObjectMapper();

        objectMapper.addMixIn(Abc.class, MixinAbc.class);

        Abc value = new Abc();

        value.firstName="bill";

        String writeValueAsString = objectMapper.writeValueAsString(value);

        Assert.assertEquals("{\"first_name\":\"bill\"}", writeValueAsString);

    }

}

编辑：addMixInAnnotation 已弃用，现在只是 addMixIn。