Question

我有一个类似于Diff的类：

public class Diff {

    private String path;
    private String value;
    private Operation operation;

    public enum Operation {
        ADD, REPLACE, REMOVE
    }

    // getters and setters
}

我想使用以下调用创建一个json节点：

ObjectMapper mapper = new ObjectMapper();
mapper.valueToTree(diffObject);

如果我有这样的差异：

Diff diff = new Diff();
diff.setPath("/path");
diff.setValue("value");
diff.setOperation(Operation.REPLACE);

这样做的：

mapper.valueToTree(diff);

将返回：

"{"path":"/path", "value":"value","operation":"REPLACE"}"

我需要＆＃34;操作＆＃34;但是，只是＆＃34; op＆＃34;据说，有一种方法可以配置ObjectMapper，以便在何时读取＆＃34;操作＆＃34;，它会将其转换为＆＃34; op＆＃34;，但我不知道如何去做吧。有人知道吗？

Answer 1

您可以使用@JsonProperty注释

public static class Diff {

    private String path;
    private String value;

    @JsonProperty("op")
    private Operation operation;
}

<强> [UPDATE]
因为您无权访问该类，您可以使用ByteBuddy来修改该类吗？：）

例如：

@Test
public void byteBuddyManipulation() throws JsonProcessingException, IllegalAccessException, InstantiationException {
    ObjectMapper objectMapper = new ObjectMapper();

    AnnotationDescription annotationDescription = AnnotationDescription.Builder.forType(JsonProperty.class)
            .define("value", "op")
            .make();

    Class<? extends Diff> clazz = new ByteBuddy()
            .subclass(Diff.class)
            .defineField("operation", Diff.Operation.class)
            .annotateField(annotationDescription)
            .make()
            .load(Diff.class.getClassLoader(), ClassLoadingStrategy.Default.INJECTION)
            .getLoaded();

    Diff diffUpdated = clazz.newInstance();
    diffUpdated.setOperation(Diff.Operation.ADD);

    objectMapper.valueToTree(diffUpdated);   //returns "op":"ADD"
}

[更新2]
或者只是创建Diff的子类并隐藏操作字段

public static class YourDiff extends Diff {
    @JsonProperty("op")
    private Operation operation;

    @Override public Operation getOperation() {
        return operation;
    }

    @Override public void setOperation(Operation operation) {
        this.operation = operation;
    }
}

配置对象映射器以使用小写替换值

1 个答案: