小编yan*_*n89的帖子

我有一个来自jgrapht的简单有向图,我正在尝试使用jackson将其序列化为JSON文件,如下所示:

ObjectMapper mapper = new ObjectMapper();
File output = new File("P:\\tree.json");
ObjectWriter objectWriter = mapper.writer().withDefaultPrettyPrinter();
objectWriter.writeValue(output,simpleDirectedGraph);

但是我收到此错误:

Exception in thread "main" com.fasterxml.jackson.databind.JsonMappingException: No serializer found for class org.jgrapht.graph.AbstractBaseGraph$ArrayListFactory and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) ) (through reference chain: org.jgrapht.graph.SimpleDirectedGraph["edgeSetFactory"])
    at com.fasterxml.jackson.databind.ser.impl.UnknownSerializer.failForEmpty(UnknownSerializer.java:69)
    at com.fasterxml.jackson.databind.ser.impl.UnknownSerializer.serialize(UnknownSerializer.java:32)
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:693)
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:675)
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:157)
    at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:130)
    at com.fasterxml.jackson.databind.ObjectWriter$Prefetch.serialize(ObjectWriter.java:1387)
    at com.fasterxml.jackson.databind.ObjectWriter._configAndWriteValue(ObjectWriter.java:1088)
    at com.fasterxml.jackson.databind.ObjectWriter.writeValue(ObjectWriter.java:909)
    at ms.fragment.JSONTreeGenerator.main(JSONTreeGenerator.java:45)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)

我看到有一个GmlExporter,但我对json感兴趣...我怎么能这样做？