java - 将 JsonCreator 与 JsonProperty.Access.READ_ONLY 结合使用时出现 InvalidDefinitionException

Question

尝试将 @JsonCreator 与 @JsonProperty(value = "version", access = JsonProperty.Access.READ_ONLY) 一起使用时遇到 InvalidDefinitionException

这就是我的类(class)的样子:

@Entity
public class Example1 implements Serializable {

  private String field1;
  private int field2;
  private Example2 field3;

  public Example1(@JsonProperty(value = "field_1", access = JsonProperty.Access.READ_WRITE) String field1,
  @JsonProperty(value = "field_2", access = JsonProperty.Access.READ_ONLY) int field2,
  @JsonProperty(value = "field_3_1", access = JsonProperty.Access.READ_WRITE) String field31,
  @JsonProperty(value = "field_3_2", access = JsonProperty.Access.READ_WRITE) int field32
  ) {
    this.field1 = field1;
    this.field2 = field2;
    this.field3 = new Example2(field31, field32);
  }

  // getters and setters omitted
}

它抛出以下异常:

Caused by: com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Argument #1 of constructor [constructor for com.test.example.model.Example1, annotations: {interface com.fasterxml.jackson.annotation.JsonCreator=@com.fasterxml.jackson.annotation.JsonCreator(mode=DEFAULT)}] has no property name annotation; must have name when multiple-parameter constructor annotated as Creator
 at [Source: (File); line: 1, column: 1]
    at com.fasterxml.jackson.databind.exc.InvalidDefinitionException.from(InvalidDefinitionException.java:62) ~[jackson-databind-2.9.0.pr3.jar:2.9.0.pr3]
    at com.fasterxml.jackson.databind.deser.BeanDeserializerFactory.buildBeanDeserializer(BeanDeserializerFactory.java:249) ~[jackson-databind-2.9.0.pr3.jar:2.9.0.pr3]
    at com.fasterxml.jackson.databind.deser.BeanDeserializerFactory.createBeanDeserializer(BeanDeserializerFactory.java:165) ~[jackson-databind-2.9.0.pr3.jar:2.9.0.pr3]
    at com.fasterxml.jackson.databind.deser.DeserializerCache._createDeserializer2(DeserializerCache.java:411) ~[jackson-databind-2.9.0.pr3.jar:2.9.0.pr3]
    at com.fasterxml.jackson.databind.deser.DeserializerCache._createDeserializer(DeserializerCache.java:349) ~[jackson-databind-2.9.0.pr3.jar:2.9.0.pr3]
    at com.fasterxml.jackson.databind.deser.DeserializerCache._createAndCache2(DeserializerCache.java:264) ~[jackson-databind-2.9.0.pr3.jar:2.9.0.pr3]
    at com.fasterxml.jackson.databind.deser.DeserializerCache._createAndCacheValueDeserializer(DeserializerCache.java:244) ~[jackson-databind-2.9.0.pr3.jar:2.9.0.pr3]
    at com.fasterxml.jackson.databind.deser.DeserializerCache.findValueDeserializer(DeserializerCache.java:142) ~[jackson-databind-2.9.0.pr3.jar:2.9.0.pr3]
    at com.fasterxml.jackson.databind.DeserializationContext.findRootValueDeserializer(DeserializationContext.java:477) ~[jackson-databind-2.9.0.pr3.jar:2.9.0.pr3]
    at com.fasterxml.jackson.databind.ObjectMapper._findRootDeserializer(ObjectMapper.java:4145) ~[jackson-databind-2.9.0.pr3.jar:2.9.0.pr3]
    at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:3995) ~[jackson-databind-2.9.0.pr3.jar:2.9.0.pr3]
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2878) ~[jackson-databind-2.9.0.pr3.jar:2.9.0.pr3]

我的环境详细信息:我使用的是 Spring Boot 2.0.0.M2 版本和 Jackson 2.9.0.pr3。

我的目的是在反序列化期间省略field2。

我尝试在field2的setter方法中使用@JsonIgnore作为替代。甚至，它不适用于 @JsonCreator。

Answer 1

反序列化时有两种方法可以忽略该属性

1. 使用READ_ONLY

只需向您不想反序列化的属性添加注释

@JsonProperty(access = Access.READ_ONLY)
private String readOnly;

使用@JsonIgnore和@JsonProperty

这个方法要小心，你应该把@JsonIgnore放在setter之前，把@JsonProperty放在getter之前。并且属性应该清晰，没有任何注释。

@JsonProperty
public String getJsonIgnoreSetter() {
    return jsonIgnoreSetter;
}

@JsonIgnore
public void setJsonIgnoreSetter(String jsonIgnoreSetter) {
    this.jsonIgnoreSetter = jsonIgnoreSetter;
}

最后是@JsonIgnore、@JsonProperty、@JsonProperty(access = xxx)的完整注解示例。

bean的定义

public class MockBean{

    public MockBean() {
        super(MockBean.class);
    }

    public MockBean(String attr1, String ignore, String jsonIgnore, String jsonIgnoreGetter,
            String jsonIgnoreSetter, String jsonIgnoreProperties, String jsonIgnorePropertiesSetter,
            String jsonIgnorePropertiesGetter, String readOnly, String writeOnly) {
        super(MockBean.class);
        this.attr1 = attr1;
        this.ignore = ignore;
        this.jsonIgnore = jsonIgnore;
        this.jsonIgnoreGetter = jsonIgnoreGetter;
        this.jsonIgnoreSetter = jsonIgnoreSetter;
        this.jsonIgnoreProperties = jsonIgnoreProperties;
        this.jsonIgnorePropertiesSetter = jsonIgnorePropertiesSetter;
        this.jsonIgnorePropertiesGetter = jsonIgnorePropertiesGetter;
        this.readOnly = readOnly;
        this.writeOnly = writeOnly;
    }

    public String getAttr1() {
        return attr1;
    }

    public void setAttr1(String name) {
        this.attr1 = name;
    }

    public String getIgnore() {
        return ignore;
    }

    public void setIgnore(String ignore) {
        this.ignore = ignore;
    }

    public String getJsonIgnore() {
        return jsonIgnore;
    }

    public void setJsonIgnore(String jsonIgnore) {
        this.jsonIgnore = jsonIgnore;
    }

    @JsonIgnore
    public String getJsonIgnoreGetter() {
        return jsonIgnoreGetter;
    }

    @JsonProperty
    public void setJsonIgnoreGetter(String jsonIgnoreGetter) {
        this.jsonIgnoreGetter = jsonIgnoreGetter;
    }

    @JsonProperty
    public String getJsonIgnoreSetter() {
        return jsonIgnoreSetter;
    }

    @JsonIgnore
    public void setJsonIgnoreSetter(String jsonIgnoreSetter) {
        this.jsonIgnoreSetter = jsonIgnoreSetter;
    }

    public String getJsonIgnoreProperties() {
        return jsonIgnoreProperties;
    }

    public void setJsonIgnoreProperties(String jsonIgnoreProperties) {
        this.jsonIgnoreProperties = jsonIgnoreProperties;
    }

    public String getJsonIgnorePropertiesSetter() {
        return jsonIgnorePropertiesSetter;
    }

    @JsonIgnoreProperties
    public void setJsonIgnorePropertiesSetter(String jsonIgnorePropertiesSetter) {
        this.jsonIgnorePropertiesSetter = jsonIgnorePropertiesSetter;
    }

    @JsonIgnoreProperties
    public String getJsonIgnorePropertiesGetter() {
        return jsonIgnorePropertiesGetter;
    }

    public void setJsonIgnorePropertiesGetter(String jsonIgnorePropertiesGetter) {
        this.jsonIgnorePropertiesGetter = jsonIgnorePropertiesGetter;
    }

    public String getReadOnly() {
        return readOnly;
    }

    public void setReadOnly(String readOnly) {
        this.readOnly = readOnly;
    }

    public String getWriteOnly() {
        return writeOnly;
    }

    public void setWriteOnly(String writeOnly) {
        this.writeOnly = writeOnly;
    }

    private String attr1;
    @Ignore
    private String ignore;
    @JsonIgnore
    private String jsonIgnore;
    @JsonIgnore
    private String jsonIgnoreGetter;
    @JsonIgnore
    private String jsonIgnoreSetter;
    @JsonIgnoreProperties
    private String jsonIgnoreProperties;
    private String jsonIgnorePropertiesSetter;
    private String jsonIgnorePropertiesGetter;
    @JsonProperty(access = Access.READ_ONLY)
    private String readOnly;
    @JsonProperty(access = Access.WRITE_ONLY)
    private String writeOnly;
}

测试 JSON

{
  "name": "name",
  "description": "description",
  "attr1":"attr1",
  "ignore": "ignore",
  "jsonIgnore": "jsonIgnore",
  "jsonIgnoreGetter": "jsonIgnoreGetter",
  "jsonIgnoreSetter": "jsonIgnoreSetter",
  "jsonIgnoreProperties": "jsonIgnoreProperties",
  "jsonIgnorePropertiesSetter": "jsonIgnorePropertiesSetter",
  "jsonIgnorePropertiesGetter": "jsonIgnorePropertiesGetter",
  "readOnly": "readOnly",
  "writeOnly": "writeOnly"
}

反序列化结果:如果值为null，则不反序列化。