Question

当尝试将double值映射/设置为0.0时，ObjectMapper会将其视为等于null，从而在进行相等性比较时排除在外。

我有以下测试用例：

import com.fasterxml.jackson.annotation.JsonInclude.Include;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.util.Map;
import lombok.Getter;
import lombok.Setter;
import net.javacrumbs.jsonunit.JsonAssert;
import org.junit.Test;

public class ValidJson {

@Getter
@Setter
static class Temp {
  Double dblValue;
  Integer intVal;
  boolean valid = false;
}

@Test
public void validJson() throws Exception {
    ObjectMapper objectMapper = new ObjectMapper();
    objectMapper.setSerializationInclusion(Include.NON_NULL);
    objectMapper.setSerializationInclusion(Include.NON_DEFAULT);

    String json = "{\"dblValue\":0.0}";
    Temp generatedObj = objectMapper.readValue(json, Temp.class);
    Map<?, ?> originalJsonMap = objectMapper.readValue(json, Map.class);

    JsonNode generatedObjMap = objectMapper.valueToTree(generatedObj);
    JsonNode originalObjMap = objectMapper.valueToTree(originalJsonMap);
    Assert.assertSame(originalObjMap, generatedObjMap);
  }
}

上述测试用例失败，断言错误为java.lang.AssertionError: JSON documents are different: Different keys found in node "". Expected [dblValue], got []. Missing: "dblValue"

但是当我将String json = "{\"dblValue\":0.0}";更改为String json = "{\"dblValue\":1.0}";时，测试就会通过。

我认为Double与Jackson一起使用默认值行为时，我无法解决并解决上述问题。杰克逊v2.8.10。

Answer 1

问题出在这里：

objectMapper.setSerializationInclusion(Include.NON_DEFAULT);

双精度值0.0被视为默认值，而Jackson忽略了它。删除此行后，一切都应正常工作。如果您不希望包含布尔有效=假，请为有效字段添加 @JsonInclude 注释，如下所示：

@JsonInclude(Include.NON_DEFAULT)
boolean valid = false;

杰克逊序列化不包含double值0.0

1 个答案: