【jackson异常】com.fasterxml.jackson.databind.JsonMappingException异常处理方法

项目中，父层是Car.java【车辆实体】 子层是CarCommonParam.java【车辆基本信息实体】，一种车辆对用多个车辆的基本信息

但是在查询文集库这个实体的时候报错：【com.fasterxml.jackson.databind.JsonMappingException】

com.fasterxml.jackson.databind.JsonMappingException: No serializer found for class org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) ) (through reference chain: cn.skyable.zulin.common.bean.CarCommonParam_$$_jvst95e_39["handler"])
X-Zc-Ack-->null
	at com.fasterxml.jackson.databind.ser.impl.UnknownSerializer.failForEmpty(UnknownSerializer.java:59)
	at com.fasterxml.jackson.databind.ser.impl.UnknownSerializer.serialize(UnknownSerializer.java:26)
	at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:541)
	at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:644)
	at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:152)
	at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:114)
	at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:1837)
	at com.fasterxml.jackson.core.base.GeneratorBase.writeObject(GeneratorBase.java:261)
	at com.ablecloud.cloudservice.ACObjectMarshaller.marshalArray(ACObjectMarshaller.java:53)
	at com.ablecloud.cloudservice.ACObjectMarshaller.marshalObject(ACObjectMarshaller.java:37)
	at com.ablecloud.cloudservice.ACObjectMarshaller.marshal(ACObjectMarshaller.java:22)
	at com.ablecloud.common.ACObject.toString(ACObject.java:415)
	at java.lang.String.valueOf(String.java:2994)
	at java.lang.StringBuilder.append(StringBuilder.java:131)
	at cn.skyable.zulin.BaseTest.dealResp(BaseTest.java:88)
	at cn.skyable.zulin.logistics.TestLogistics.TestlistCarsByLogId(TestLogistics.java:65)
	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:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
	at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:539)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:761)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:461)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:207)

错误描述： 由于会发生 循环引用的问题，因此在实体中进行了截断即子层可以查到父层的信息，但是父层查不到子层的信息。

解决方案：

将父层Car.java中

改为

即可！！！！