java - 当我尝试使用 Spring RestTemplate 检索对象时，为什么 Lombok 注释似乎不起作用？
问题描述
我正在开发一个 Spring Boot 项目，我正在尝试使用 Lombok 来避免在我的域类中定义空的样板代码，例如空构造函数和 getter\setter 方法。
但它似乎不像我预期的那样工作。
这是我的 DTO 课程：
@Getter
@Setter
@NoArgsConstructor
public class NotaryDistrict {
String idDistrict;
String denominazione;
String regione;
String provincia;
ArrayList<Localita> localita;
public NotaryDistrict(String idDistrict, String denominazione, String regione, String provincia,
ArrayList<Localita> localita) {
super();
this.idDistrict = idDistrict;
this.denominazione = denominazione;
this.regione = regione;
this.provincia = provincia;
this.localita = localita;
}
}
如您所见，我的域类使用以下注释：
- @NoArgsConstructor：避免声明空构造函数。
- @Getter：避免声明 getter 方法。
- @Setter：避免声明 setter 方法。
然后在我的代码中，我使用RestTemplate执行外部 API 调用：
ResponseEntity<NotaryDistrict[]> response = restTemplate.getForEntity(notartelApiUrl, NotaryDistrict[].class);
NotaryDistrict[] notaryDistrictList = response.getBody();
因此，在这种情况下，执行getForEntity()方法会给我以下错误，它与前一个域类中缺少的空构造函数有关：
[2m2021-08-06 15:30:24.423[0;39m [31mERROR[0;39m [35m9160[0;39m [2m---[0;39m [2m[ scheduling-1][0;39m [36mo.s.batch.core.step.AbstractStep [0;39m [2m:[0;39m Encountered an error executing step exampleJobStep in job exampleJob
org.springframework.http.converter.HttpMessageConversionException: Type definition error: [simple type, class com.notariato.updateInfo.domain.NotaryDistrict]; nested exception is com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot construct instance of `com.notariato.updateInfo.domain.NotaryDistrict` (no Creators, like default constructor, exist): cannot deserialize from Object value (no delegate- or property-based Creator)
at [Source: (PushbackInputStream); line: 1, column: 3] (through reference chain: java.lang.Object[][0])
at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:386) ~[spring-web-5.3.9.jar:5.3.9]
at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.read(AbstractJackson2HttpMessageConverter.java:342) ~[spring-web-5.3.9.jar:5.3.9]
at org.springframework.web.client.HttpMessageConverterExtractor.extractData(HttpMessageConverterExtractor.java:105) ~[spring-web-5.3.9.jar:5.3.9]
at org.springframework.web.client.RestTemplate$ResponseEntityResponseExtractor.extractData(RestTemplate.java:1037) ~[spring-web-5.3.9.jar:5.3.9]
at org.springframework.web.client.RestTemplate$ResponseEntityResponseExtractor.extractData(RestTemplate.java:1020) ~[spring-web-5.3.9.jar:5.3.9]
at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:778) ~[spring-web-5.3.9.jar:5.3.9]
at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:711) ~[spring-web-5.3.9.jar:5.3.9]
at org.springframework.web.client.RestTemplate.getForEntity(RestTemplate.java:361) ~[spring-web-5.3.9.jar:5.3.9]
at com.notariato.updateInfo.RESTStudentReader.fetchStudentDataFromAPI(RESTStudentReader.java:105) ~[classes/:na]
at com.notariato.updateInfo.RESTStudentReader.read(RESTStudentReader.java:69) ~[classes/:na]
at com.notariato.updateInfo.RESTStudentReader.read(RESTStudentReader.java:1) ~[classes/:na]
at org.springframework.batch.core.step.item.SimpleChunkProvider.doRead(SimpleChunkProvider.java:99) ~[spring-batch-core-4.3.3.jar:4.3.3]
at org.springframework.batch.core.step.item.SimpleChunkProvider.read(SimpleChunkProvider.java:180) ~[spring-batch-core-4.3.3.jar:4.3.3]
at org.springframework.batch.core.step.item.SimpleChunkProvider$1.doInIteration(SimpleChunkProvider.java:126) ~[spring-batch-core-4.3.3.jar:4.3.3]
at org.springframework.batch.repeat.support.RepeatTemplate.getNextResult(RepeatTemplate.java:375) ~[spring-batch-infrastructure-4.3.3.jar:4.3.3]
at org.springframework.batch.repeat.support.RepeatTemplate.executeInternal(RepeatTemplate.java:215) ~[spring-batch-infrastructure-4.3.3.jar:4.3.3]
at org.springframework.batch.repeat.support.RepeatTemplate.iterate(RepeatTemplate.java:145) ~[spring-batch-infrastructure-4.3.3.jar:4.3.3]
at org.springframework.batch.core.step.item.SimpleChunkProvider.provide(SimpleChunkProvider.java:118) ~[spring-batch-core-4.3.3.jar:4.3.3]
at org.springframework.batch.core.step.item.ChunkOrientedTasklet.execute(ChunkOrientedTasklet.java:71) ~[spring-batch-core-4.3.3.jar:4.3.3]
at org.springframework.batch.core.step.tasklet.TaskletStep$ChunkTransactionCallback.doInTransaction(TaskletStep.java:407) ~[spring-batch-core-4.3.3.jar:4.3.3]
at org.springframework.batch.core.step.tasklet.TaskletStep$ChunkTransactionCallback.doInTransaction(TaskletStep.java:331) ~[spring-batch-core-4.3.3.jar:4.3.3]
at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:140) ~[spring-tx-5.3.9.jar:5.3.9]
at org.springframework.batch.core.step.tasklet.TaskletStep$2.doInChunkContext(TaskletStep.java:273) ~[spring-batch-core-4.3.3.jar:4.3.3]
at org.springframework.batch.core.scope.context.StepContextRepeatCallback.doInIteration(StepContextRepeatCallback.java:82) ~[spring-batch-core-4.3.3.jar:4.3.3]
at org.springframework.batch.repeat.support.RepeatTemplate.getNextResult(RepeatTemplate.java:375) ~[spring-batch-infrastructure-4.3.3.jar:4.3.3]
at org.springframework.batch.repeat.support.RepeatTemplate.executeInternal(RepeatTemplate.java:215) ~[spring-batch-infrastructure-4.3.3.jar:4.3.3]
at org.springframework.batch.repeat.support.RepeatTemplate.iterate(RepeatTemplate.java:145) ~[spring-batch-infrastructure-4.3.3.jar:4.3.3]
at org.springframework.batch.core.step.tasklet.TaskletStep.doExecute(TaskletStep.java:258) ~[spring-batch-core-4.3.3.jar:4.3.3]
at org.springframework.batch.core.step.AbstractStep.execute(AbstractStep.java:208) ~[spring-batch-core-4.3.3.jar:4.3.3]
at org.springframework.batch.core.job.SimpleStepHandler.handleStep(SimpleStepHandler.java:152) ~[spring-batch-core-4.3.3.jar:4.3.3]
at org.springframework.batch.core.job.flow.JobFlowExecutor.executeStep(JobFlowExecutor.java:68) ~[spring-batch-core-4.3.3.jar:4.3.3]
at org.springframework.batch.core.job.flow.support.state.StepState.handle(StepState.java:68) ~[spring-batch-core-4.3.3.jar:4.3.3]
at org.springframework.batch.core.job.flow.support.SimpleFlow.resume(SimpleFlow.java:169) ~[spring-batch-core-4.3.3.jar:4.3.3]
at org.springframework.batch.core.job.flow.support.SimpleFlow.start(SimpleFlow.java:144) ~[spring-batch-core-4.3.3.jar:4.3.3]
at org.springframework.batch.core.job.flow.FlowJob.doExecute(FlowJob.java:137) ~[spring-batch-core-4.3.3.jar:4.3.3]
at org.springframework.batch.core.job.AbstractJob.execute(AbstractJob.java:320) ~[spring-batch-core-4.3.3.jar:4.3.3]
at org.springframework.batch.core.launch.support.SimpleJobLauncher$1.run(SimpleJobLauncher.java:149) ~[spring-batch-core-4.3.3.jar:4.3.3]
at org.springframework.core.task.SyncTaskExecutor.execute(SyncTaskExecutor.java:50) ~[spring-core-5.3.9.jar:5.3.9]
at org.springframework.batch.core.launch.support.SimpleJobLauncher.run(SimpleJobLauncher.java:140) ~[spring-batch-core-4.3.3.jar:4.3.3]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:78) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Method.java:567) ~[na:na]
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:344) ~[spring-aop-5.3.9.jar:5.3.9]
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:198) ~[spring-aop-5.3.9.jar:5.3.9]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.3.9.jar:5.3.9]
at org.springframework.batch.core.configuration.annotation.SimpleBatchConfiguration$PassthruAdvice.invoke(SimpleBatchConfiguration.java:128) ~[spring-batch-core-4.3.3.jar:4.3.3]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.9.jar:5.3.9]
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:215) ~[spring-aop-5.3.9.jar:5.3.9]
at jdk.proxy2/jdk.proxy2.$Proxy58.run(Unknown Source) ~[na:na]
at com.notariato.updateInfo.SpringBatchExampleJobLauncher.runSpringBatchExampleJob(SpringBatchExampleJobLauncher.java:42) ~[classes/:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:78) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Method.java:567) ~[na:na]
at org.springframework.scheduling.support.ScheduledMethodRunnable.run(ScheduledMethodRunnable.java:84) ~[spring-context-5.3.9.jar:5.3.9]
at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:54) ~[spring-context-5.3.9.jar:5.3.9]
at org.springframework.scheduling.concurrent.ReschedulingRunnable.run(ReschedulingRunnable.java:95) ~[spring-context-5.3.9.jar:5.3.9]
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515) ~[na:na]
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[na:na]
at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) ~[na:na]
at java.base/java.lang.Thread.run(Thread.java:831) ~[na:na]
Caused by: com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot construct instance of `com.notariato.updateInfo.domain.NotaryDistrict` (no Creators, like default constructor, exist): cannot deserialize from Object value (no delegate- or property-based Creator)
at [Source: (PushbackInputStream); line: 1, column: 3] (through reference chain: java.lang.Object[][0])
at com.fasterxml.jackson.databind.exc.InvalidDefinitionException.from(InvalidDefinitionException.java:67) ~[jackson-databind-2.12.4.jar:2.12.4]
at com.fasterxml.jackson.databind.DeserializationContext.reportBadDefinition(DeserializationContext.java:1764) ~[jackson-databind-2.12.4.jar:2.12.4]
at com.fasterxml.jackson.databind.DatabindContext.reportBadDefinition(DatabindContext.java:400) ~[jackson-databind-2.12.4.jar:2.12.4]
at com.fasterxml.jackson.databind.DeserializationContext.handleMissingInstantiator(DeserializationContext.java:1209) ~[jackson-databind-2.12.4.jar:2.12.4]
at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromObjectUsingNonDefault(BeanDeserializerBase.java:1415) ~[jackson-databind-2.12.4.jar:2.12.4]
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:362) ~[jackson-databind-2.12.4.jar:2.12.4]
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:195) ~[jackson-databind-2.12.4.jar:2.12.4]
at com.fasterxml.jackson.databind.deser.std.ObjectArrayDeserializer.deserialize(ObjectArrayDeserializer.java:214) ~[jackson-databind-2.12.4.jar:2.12.4]
at com.fasterxml.jackson.databind.deser.std.ObjectArrayDeserializer.deserialize(ObjectArrayDeserializer.java:24) ~[jackson-databind-2.12.4.jar:2.12.4]
at com.fasterxml.jackson.databind.deser.DefaultDeserializationContext.readRootValue(DefaultDeserializationContext.java:322) ~[jackson-databind-2.12.4.jar:2.12.4]
at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4593) ~[jackson-databind-2.12.4.jar:2.12.4]
at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3601) ~[jackson-databind-2.12.4.jar:2.12.4]
at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:378) ~[spring-web-5.3.9.jar:5.3.9]
... 63 common frames omitted
如果我现在将空构造函数添加到前一个域类（NotaryDistrict），我不会得到任何错误。getForEntity ()完成，但现在对象进入检索数组：
NotaryDistrict[] notaryDistrictList = response.getBody();
包含空字段（因为 Lombok @Setter和@Getter注释似乎没有按预期工作）。
相反，如果我声明了空的构造函数以及我所有的 getter 和 setter 方法，它会按预期工作，并且我正确地获得了按预期初始化字段的数组。
为什么？可能是什么问题呢？我该如何尝试解决此问题？
解决方案
您可以将 lombok 依赖项添加到 pom.xml 文件中，并配置 java 编译器预处理器以在编译类时使用它。
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