尝试使用自定义 JsonSerializer (Jackson) 时出现 Stackoverflow 异常

Question

我正在尝试使用 Jackson 将对象序列化为 JSON，以便字段名称基于字段类型。

我和this线程中的OP有同样的问题：

但是，它不起作用。

我正在使用 Wildfly 10.1 Final

我做了以下事情：

• 添加了resteasy-jackson2 依赖项，提供给pom.xml。
• 创建了我链接的帖子中指定的 CustomSerializer 类。

CustomSerializer 类：

public class CustomSerializer extends JsonSerializer<Object> {
  public void serialize(Object value, JsonGenerator jgen, SerializerProvider provider) throws IOException, JsonProcessingException {
    jgen.writeStartObject();
    jgen.writeObjectField(value.getClass().getSimpleName(), value);
    jgen.writeEndObject();
  }
}

• 在对象字段中添加了@JsonProperty("data") 注释，所以我的 Response 类现在看起来像这样：

  public class ResponseWithReturnValue extends Response {
      @JsonProperty("data")
      private Object object;
  
      public ResponseWithReturnValue (int code, String msg) {
          super(code, msg);
      }
  
      public Object getObject() {
          return object;
      }
  
      public void setObject(Object object) {
          this.object = object;
      }
  }
  

当我测试它时，我得到以下 json 对象：

{"code":0,"message":"Success","data":"test"}

因此，@JsonProperty 注释可以正常工作，但自定义 JsonSerializer 不能。

现在，我尝试了 this 博客中的建议，并在我的 ResponseWithReturnValue 类中添加了 @JsonSerialize(using=CustomSerializer.class) 注释。

但是，现在我得到了这个 StackOverflow :) 异常：

Exception in thread "main" java.lang.StackOverflowError
at java.lang.Class.getEnclosingMethodInfo(Class.java:1072)
at java.lang.Class.getEnclosingClass(Class.java:1272)
at java.lang.Class.getSimpleBinaryName(Class.java:1443)
at java.lang.Class.getSimpleName(Class.java:1309)
at rs.netset.authority.web.facade.utils.CustomSerializer.serialize(CustomSerializer.java:13)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:130)
at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:2383)
at com.fasterxml.jackson.core.base.GeneratorBase.writeObject(GeneratorBase.java:324)
at com.fasterxml.jackson.core.JsonGenerator.writeObjectField(JsonGenerator.java:1415)
at rs.netset.authority.web.facade.utils.CustomSerializer.serialize(CustomSerializer.java:13)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:130)
at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:2383)
at com.fasterxml.jackson.core.base.GeneratorBase.writeObject(GeneratorBase.java:324)
at com.fasterxml.jackson.core.JsonGenerator.writeObjectField(JsonGenerator.java:1415)
at rs.netset.authority.web.facade.utils.CustomSerializer.serialize(CustomSerializer.java:13)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:130)
at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:2383)
at com.fasterxml.jackson.core.base.GeneratorBase.writeObject(GeneratorBase.java:324)
at com.fasterxml.jackson.core.JsonGenerator.writeObjectField(JsonGenerator.java:1415)
at rs.netset.authority.web.facade.utils.CustomSerializer.serialize(CustomSerializer.java:13)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:130)
at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:2383)
at com.fasterxml.jackson.core.base.GeneratorBase.writeObject(GeneratorBase.java:324)
at com.fasterxml.jackson.core.JsonGenerator.writeObjectField(JsonGenerator.java:1415)
at rs.netset.authority.web.facade.utils.CustomSerializer.serialize(CustomSerializer.java:13)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:130)
at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:2383)
at com.fasterxml.jackson.core.base.GeneratorBase.writeObject(GeneratorBase.java:324)
at com.fasterxml.jackson.core.JsonGenerator.writeObjectField(JsonGenerator.java:1415)
at rs.netset.authority.web.facade.utils.CustomSerializer.serialize(CustomSerializer.java:13)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:130)
at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:2383)
at com.fasterxml.jackson.core.base.GeneratorBase.writeObject(GeneratorBase.java:324)
at com.fasterxml.jackson.core.JsonGenerator.writeObjectField(JsonGenerator.java:1415)
at rs.netset.authority.web.facade.utils.CustomSerializer.serialize(CustomSerializer.java:13)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:130)
at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:2383)
at com.fasterxml.jackson.core.base.GeneratorBase.writeObject(GeneratorBase.java:324)
at com.fasterxml.jackson.core.JsonGenerator.writeObjectField(JsonGenerator.java:1415)
at rs.netset.authority.web.facade.utils.CustomSerializer.serialize(CustomSerializer.java:13)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:130)
at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:2383)
at com.fasterxml.jackson.core.base.GeneratorBase.writeObject(GeneratorBase.java:324)
at com.fasterxml.jackson.core.JsonGenerator.writeObjectField(JsonGenerator.java:1415)
at rs.netset.authority.web.facade.utils.CustomSerializer.serialize(CustomSerializer.java:13)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:130)
at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:2383)

我无法发布完整的堆栈跟踪，因为它太长了。

有什么想法吗？

Answer 1

您通过始终委托给同一个（您的自定义）序列化程序创建了一个无限递归。 jgen.writeObjectField(value.getClass().getSimpleName(), value); 行调用您的自定义序列化程序以序列化Object，它再次调用jgen.writeObjectField(...) 等等。

您可以委托给另一个序列化程序或实际序列化对象：

jgen.writeObjectFieldStart("objectFieldName");
jgen.writeStringField("someValue", value.getSomeValue());
//...
jgen.writeEndObject();