java - 动态添加fasterxml注解？

Question

有没有办法动态设置@JsonProperty注释，例如:

class A {

    @JsonProperty("newB") //adding this dynamically
    private String b;

}

或者我可以简单地重命名实例的字段吗？如果是这样，请给我一个想法。另外，ObjectMapper 可以通过什么方式与序列化一起使用？

Answer 1

假设您的 POJO 类如下所示:

class PojoA {

    private String b;

    // getters, setters
}

现在，您必须创建 MixIn界面:

interface PojoAMixIn {

    @JsonProperty("newB")
    String getB();
}

简单用法:

PojoA pojoA = new PojoA();
pojoA.setB("B value");

System.out.println("Without MixIn:");
ObjectMapper mapper = new ObjectMapper();
System.out.println(mapper.writerWithDefaultPrettyPrinter().writeValueAsString(pojoA));

System.out.println("With MixIn:");
ObjectMapper mapperWithMixIn = new ObjectMapper();
mapperWithMixIn.addMixInAnnotations(PojoA.class, PojoAMixIn.class);
System.out.println(mapperWithMixIn.writerWithDefaultPrettyPrinter().writeValueAsString(pojoA));

上面的程序打印:

Without MixIn:
{
  "b" : "B value"
}
With MixIn:
{
  "newB" : "B value"
}