Java 使用 Jackson 将对象转储到 String
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/9767131/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
dump object to String with Hymanson
提问by turbanoff
I'm using Gson to generate debug ouput in my application
我正在使用 Gson 在我的应用程序中生成调试输出
Gson gson = new GsonBuilder().setPrettyPrinting().serializeNulls().create();
gson.toJson(myObject);
But Gson does complain about a circular reference error when attempting to serialize a data structure. Can this be done with Hymanson library?
但是 Gson 在尝试序列化数据结构时确实会抱怨循环引用错误。这可以用Hyman逊图书馆完成吗？
UPDGson 2.3.1: Released Nov 20, 2014
UPDGson 2.3.1：2014 年 11 月 20 日发布
Added support to serialize objects with self-referential fields. The self-referential field is set to null in JSON. Previous version of Gson threw a StackOverflowException on encountering any self-referential fields.
The most visible impact of this is that Gson can now serialize Throwable (Exception and Error)
采纳答案by Bruno Grieder
To serialize with Hymanson:
与Hyman逊序列化：
public String serialize(Object obj, boolean pretty) {
ObjectMapper mapper = new ObjectMapper();
mapper.configure(SerializationConfig.Feature.FAIL_ON_EMPTY_BEANS, false);
if (pretty) {
return mapper.writerWithDefaultPrettyPrinter().writeValueAsString(obj);
}
return mapper.writeValueAsString(obj);
}
回答by beerbajay
Hymanson can deal with cycles in the object graph with:
Hymanson 可以通过以下方式处理对象图中的循环：
@JsonIgnore, where you omit the property entirely@JsonManagedReferenceand@JsonBackReference- a custom Serializer which extends
JsonSerializer
@JsonIgnore，您完全省略了该属性@JsonManagedReference和@JsonBackReference- 扩展的自定义序列化程序
JsonSerializer
You would use JsonSerializerwhen you still wish to provide some information about the object but want to omit certain fields (the ones causing the cycle). For example:
JsonSerializer当您仍然希望提供有关对象的一些信息但希望省略某些字段（导致循环的字段）时，您可以使用。例如：
import org.codehaus.Hymanson.map.JsonSerializer
import org.codehaus.Hymanson.JsonGenerator;
import org.codehaus.Hymanson.JsonProcessingException;
import org.codehaus.Hymanson.map.SerializerProvider;
import java.io.IOException;
public class ParentReferenceSerializer extends JsonSerializer<Parent> {
@Override
public void serialize(Parent parent, JsonGenerator jgen,
SerializerProvider provider)
throws IOException, JsonProcessingException {
jgen.writeStartObject();
writeNumberField(jgen, "id", parent.getId());
// ... other fields ...
jgen.writeEndObject();
}
}
Then in the class in which is being serialized, you'd use a @JsonSerializeannotation:
然后在正在序列化的类中，您将使用@JsonSerialize注释：
@JsonSerialize(using = ParentReferenceSerializer.class)
public Parent getParent() {
return parent;
}
