即使使用NON_NULL，Jackson ObjectMap也会抛出NullPointerException [英] Jackson ObjectMapper throwing NullPointerException even with NON_NULL
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问题描述
当使用以下JSON且phones或emailAddresses为空时，我收到NullPointerException。
When the following JSON is used and either "phones" or "emailAddresses" are null, I'm getting a NullPointerException.
JSON：
{
"item": {
"messages": {
"user.phone.missing": {
"type": "warning",
"key": "user.phone.missing",
"message": "User profile does not have a phone number",
"code": null
},
"user.email.missing": {
"type": "warning",
"key": "user.email.missing",
"message": "User profile does not have an email address",
"code": null
},
"user.es.sync.failed": {
"type": "error",
"key": "user.es.sync.failed",
"message": "Unable to sync user",
"code": null
}
},
"user": {
"firstName": "Test",
"middleInitial": null,
"lastName": "User",
"createdDt": "2016-04-20 19:50:03+0000",
"updatedDt": null,
"lastVerifiedDt": null,
"status": "DEACTIVATED",
"tokens": [
{
"tokenHash": "test hash",
"tokenValue": "test dn",
"createdDt": "2016-04-20 19:50:03+0000",
"updatedDt": null,
"status": "ENABLED"
}
],
"phones": null,
"emailAddresses": null
}
},
"status": "SUCCESS",
"errors": []
}
这是堆栈跟踪：
Exception in thread "main" com.fasterxml.jackson.databind.JsonMappingException: N/A (through reference chain: com.test.message.cte.CteItemResponse["item"]->com.test.message.cte.CteUserContext["user"]->com.test.User["phones"])
at com.fasterxml.jackson.databind.deser.SettableBeanProperty._throwAsIOE(SettableBeanProperty.java:510)
at com.fasterxml.jackson.databind.deser.SettableBeanProperty._throwAsIOE(SettableBeanProperty.java:493)
at com.fasterxml.jackson.databind.deser.impl.MethodProperty.set(MethodProperty.java:116)
at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:98)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:295)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:121)
at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:464)
at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:98)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:295)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:121)
at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:464)
at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:98)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:295)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:121)
at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:2888)
at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2041)
at com.test.Test.main(Test.java:20)
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 com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
Caused by: java.lang.NullPointerException
at com.test.User.setPhones(User.java:202)
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 com.fasterxml.jackson.databind.deser.impl.MethodProperty.set(MethodProperty.java:114)
... 19 more
我正在设置我的自定义ObjectMapper：
I'm setting up my custom ObjectMapper like this:
package com.test;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.util.ISO8601DateFormat;
public class MigrationObjectMapper extends ObjectMapper {
private MigrationObjectMapper() {
// do not serialize null value fields
this.setSerializationInclusion(JsonInclude.Include.NON_NULL);
configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
}
public static MigrationObjectMapper getMigrationObjectMapper(){
return new MigrationObjectMapper();
}
}
这意味着 CteUserContext cteUserContext = MigrationObjectMapper.getMigrationObjectMapper（）。convertValue（item.getItem（），new TypeReference< CteUserContext>（）{}）; 抛出错误。
Inside CteUserContext是一个User对象，它包含List和List。这些不应该根据对象映射器配置进行序列化吗？
Inside CteUserContext is a User object, which contains List and List. Shouldn't these just not be serialized based on the object mapper configuration?
推荐答案
Per Rocki的评论：
Per Rocki's comment:
setSerializationInclusion仅对
序列化而非反序列化忽略空值。
setSerializationInclusion will ignore null values only for serialization not deserialization.
如果我的User类中传入的phones值为null，我没有处理，所以它正在抛出NPE。我已更新以确认它不为空。如果是，它会在任何其他逻辑之前短路：
I wasn't handling if the incoming "phones" value was null in my User class, so it was throwing the NPE. I've updated to confirm that it isn't null. If it is, it'll short circuit before any other logic:
/**
* @param phones The phones
*/
@JsonProperty("phones")
public void setPhones(List<Phone> phones) {
if ((phones != null) && (phones.size() > 1)) {
int primaryIndex = -1;
Phone primaryPhone = null;
for (Phone p : phones) {
if (p.getIsPrimary()) {
primaryIndex = phones.indexOf(p);
primaryPhone = p;
break;
}
}
phones.remove(primaryIndex);
phones.add(0, primaryPhone);
}
this.phones = phones;
}
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