Jackson dynamic Pojo沙漠化

Question

拥有像下一个这样的动态POJO：

@JsonInclude(JsonInclude.Include.NON_NULL)
public class MyDynamicWrapper <T> {

    @JsonProperty("header")
    private CommonHeader header;

    @JsonProperty("payload")
    private T payload;

    public MyDynamicWrapper(CommonHeader header, T payload) {
        super();
        this.header = header;
        this.payload = payload;
    }

    public CommonHeader getHeader() {
        return header;
    }

    public void setHeader(CommonHeader header) {
        this.header = header;
    }

    public T getPayload() {
        return payload;
    }

    public void setPayload(T payload) {
        this.payload = payload;
    }
}

其中T有效负载可以是以下之一：

@JsonInclude(JsonInclude.Include.NON_NULL)
public class MyPayloadOne {

    @JsonProperty("status")
    private int status; 

    @JsonProperty("action")
    private String action;  

    ...
}

@JsonInclude(JsonInclude.Include.NON_NULL)
public class MyPayloadTwo {

    @JsonProperty("properties")
    private List<String> properties = new ArrayList<>();    

    ...
}

MyDynamicWrapper pojo = jacksonMapper.readValue(jsonMessage, MyDynamicWrapper.class);

MyDynamicWrapper<?> pojo = jacksonMapper.readValue(jsonMessage, MyDynamicWrapper.class);

Answer 1

您可以（并且应该）向readvalue传递一个TypeReference来指定要反序列化的泛型类实例的类型。例如。包装MypayLoadOne时：

TypeReference ref = new TypeReference<MyDynamicWrapper<MyPayloadOne>>(){};
MyDynamicWrapper<MyPayloadOne> pojo = jacksonMapper.readValue(jsonMessage, ref);