Question

感谢您提前帮助。能帮我找到我在这段代码中犯的错误：

＆＃13;

<script>
  function getChildrenRecursively(parent) {
    returnValue = [];
    var children = getChildren(parent);
    children.forEach(function(child, index, array) {
      itemData = new Object();
      itemData.id = parent + "_" + index + "_" + child;
      itemData.items = getChildrenRecursively(child);

      returnValue.push(itemData);
    })
    return returnValue;
  }

  function getChildren(parentId) {
    if (parentId == 1) return [2, 3];
    if (parentId == 2) return [4];
    if (parentId == 3) return [5, 6];
    if (parentId == 4) return [];
    if (parentId == 5) return [];
    if (parentId == 6) return [];
  }

  console.log(getChildrenRecursively(1));
</script>

＆＃13;

getChildrenRecursively（parentId）是一个递归方法，它收集传递父id的子节点（通过调用getChildren（parentId）），然后为每个子节点递归调用自身以收集子节点的子节点，依此类推。我期望从returnValue输出的是：

自parentId以来有2个元素的数组＆＃34; 1＆＃34;有2个孩子＆＃34; 2＆＃34;和＆＃34; 3＆＃34;。那么＆＃34; 2＆＃34;将有一个1元素的子阵列＆＃34; 4＆＃34;和＆＃34; 3＆＃34;将有一个2元素的子阵列＆＃34; 5＆＃34;和＆＃34; 6＆＃34;。但我得到了这个，每个子项都有2个孩子等等，请帮我弄清楚代码中的错误：

Answer 1

请参阅以下更改。我添加了org.springframework.http.converter.HttpMessageNotReadableException: Could not read JSON document: Invalid UTF-8 start byte 0xa0 at [Source: java.io.PushbackInputStream@84240f; line: 8, column: 31] at [Source: java.io.PushbackInputStream@84240f; line: 8, column: 29] (through reference chain: com.foo.bar.webclient.model.rest.JsonData["CustomEvents"]->com.foo.bar.webclient.model.rest.CustomEventResult["CustomEvent"]->java.util.ArrayList[0]->com.foo.bar.webclient.model.rest.CustomEvent["web_method_rest1"]); nested exception is com.fasterxml.jackson.databind.JsonMappingException: Invalid UTF-8 start byte 0xa0 at [Source: java.io.PushbackInputStream@84240f; line: 8, column: 31] at [Source: java.io.PushbackInputStream@84240f; line: 8, column: 29] (through reference chain: com.foo.bar.webclient.model.rest.JsonData["CustomEvents"]->com.foo.bar.webclient.model.rest.CustomEventResult["CustomEvent"]->java.util.ArrayList[0]->com.foo.bar.webclient.model.rest.CustomEvent["web_method_rest1"]) at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:234) at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.read(AbstractJackson2HttpMessageConverter.java:219) at org.springframework.web.client.HttpMessageConverterExtractor.extractData(HttpMessageConverterExtractor.java:95) at org.springframework.web.client.RestTemplate$ResponseEntityResponseExtractor.extractData(RestTemplate.java:917) at org.springframework.web.client.RestTemplate$ResponseEntityResponseExtractor.extractData(RestTemplate.java:901) at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:655) at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:613) at org.springframework.web.client.RestTemplate.exchange(RestTemplate.java:531) at com.foo.bar.webclient.rest.clients.RestfulRequests.getCustomEvents(RestfulRequests.java:58) at com.foo.bar.webclient.rest.clients.RestfulRequests$$FastClassBySpringCGLIB$$a04c852c.invoke(<generated>) at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204) at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:738) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157) at org.springframework.retry.interceptor.RetryOperationsInterceptor$1.doWithRetry(RetryOperationsInterceptor.java:91) at org.springframework.retry.support.RetryTemplate.doExecute(RetryTemplate.java:286) at org.springframework.retry.support.RetryTemplate.execute(RetryTemplate.java:163) at org.springframework.retry.interceptor.RetryOperationsInterceptor.invoke(RetryOperationsInterceptor.java:118) at org.springframework.retry.annotation.AnnotationAwareRetryOperationsInterceptor.invoke(AnnotationAwareRetryOperationsInterceptor.java:152) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:673) at com.foo.bar.webclient.rest.clients.RestfulRequests$$EnhancerBySpringCGLIB$$d3b75a44.getCustomEvents(<generated>) at com.foo.bar.webclient.batch.CustomEventReader.read(CustomEventReader.java:30) at com.foo.bar.webclient.batch.CustomEventReader.read(CustomEventReader.java:1) at org.springframework.batch.core.step.item.SimpleChunkProvider.doRead(SimpleChunkProvider.java:91) at org.springframework.batch.core.step.item.FaultTolerantChunkProvider.read(FaultTolerantChunkProvider.java:87) at org.springframework.batch.core.step.item.SimpleChunkProvider$1.doInIteration(SimpleChunkProvider.java:116) at org.springframework.batch.repeat.support.RepeatTemplate.getNextResult(RepeatTemplate.java:374) at org.springframework.batch.repeat.support.RepeatTemplate.executeInternal(RepeatTemplate.java:215) at org.springframework.batch.repeat.support.RepeatTemplate.iterate(RepeatTemplate.java:144) at org.springframework.batch.core.step.item.SimpleChunkProvider.provide(SimpleChunkProvider.java:110) at org.springframework.batch.core.step.item.ChunkOrientedTasklet.execute(ChunkOrientedTasklet.java:69) at org.springframework.batch.core.step.tasklet.TaskletStep$ChunkTransactionCallback.doInTransaction(TaskletStep.java:406) at org.springframework.batch.core.step.tasklet.TaskletStep$ChunkTransactionCallback.doInTransaction(TaskletStep.java:330) at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:133) at org.springframework.batch.core.step.tasklet.TaskletStep$2.doInChunkContext(TaskletStep.java:271) at org.springframework.batch.core.scope.context.StepContextRepeatCallback.doInIteration(StepContextRepeatCallback.java:81) at org.springframework.batch.repeat.support.RepeatTemplate.getNextResult(RepeatTemplate.java:374) at org.springframework.batch.repeat.support.RepeatTemplate.executeInternal(RepeatTemplate.java:215) at org.springframework.batch.repeat.support.RepeatTemplate.iterate(RepeatTemplate.java:144) at org.springframework.batch.core.step.tasklet.TaskletStep.doExecute(TaskletStep.java:257) at org.springframework.batch.core.step.AbstractStep.execute(AbstractStep.java:200) at org.springframework.batch.core.job.SimpleStepHandler.handleStep(SimpleStepHandler.java:148) at org.springframework.batch.core.job.AbstractJob.handleStep(AbstractJob.java:392) at org.springframework.batch.core.job.SimpleJob.doExecute(SimpleJob.java:135) at org.springframework.batch.core.job.AbstractJob.execute(AbstractJob.java:306) at org.springframework.batch.core.launch.support.SimpleJobLauncher$1.run(SimpleJobLauncher.java:135) at org.springframework.core.task.SyncTaskExecutor.execute(SyncTaskExecutor.java:50) at org.springframework.batch.core.launch.support.SimpleJobLauncher.run(SimpleJobLauncher.java:128) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:333) at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157) at org.springframework.batch.core.configuration.annotation.SimpleBatchConfiguration$PassthruAdvice.invoke(SimpleBatchConfiguration.java:127) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213) at com.sun.proxy.$Proxy67.run(Unknown Source) at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.execute(JobLauncherCommandLineRunner.java:214) at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.executeLocalJobs(JobLauncherCommandLineRunner.java:231) at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.launchJobFromProperties(JobLauncherCommandLineRunner.java:123) at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.run(JobLauncherCommandLineRunner.java:117) at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:776) at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:760) at org.springframework.boot.SpringApplication.afterRefresh(SpringApplication.java:747) at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) at org.springframework.boot.SpringApplication.run(SpringApplication.java:1162) at org.springframework.boot.SpringApplication.run(SpringApplication.java:1151) at com.foo.bar.webclient.MyApplication.main(MyApplication.java:10) Caused by: com.fasterxml.jackson.databind.JsonMappingException: Invalid UTF-8 start byte 0xa0 at [Source: java.io.PushbackInputStream@84240f; line: 8, column: 31] at [Source: java.io.PushbackInputStream@84240f; line: 8, column: 29] (through reference chain: com.foo.bar.webclient.model.rest.JsonData["CustomEvents"]->com.foo.bar.webclient.model.rest.CustomEventResult["CustomEvent"]->java.util.ArrayList[0]->com.foo.bar.webclient.model.rest.CustomEvent["web_method_rest1"]) at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:388) at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:348) at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.wrapAndThrow(BeanDeserializerBase.java:1600) at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:278) at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:140) at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:287) at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:259) at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:26) at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:504) at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:104) at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:276) at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:140) at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:504) at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:104) at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:276) at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:140) at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:3798) at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2922) at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:231) ... 69 common frames omitted Caused by: com.fasterxml.jackson.core.JsonParseException: Invalid UTF-8 start byte 0xa0 at [Source: java.io.PushbackInputStream@84240f; line: 8, column: 31] at com.fasterxml.jackson.core.JsonParser._constructError(JsonParser.java:1702) at com.fasterxml.jackson.core.base.ParserMinimalBase._reportError(ParserMinimalBase.java:558) at com.fasterxml.jackson.core.json.UTF8StreamJsonParser._reportInvalidInitial(UTF8StreamJsonParser.java:3544) at com.fasterxml.jackson.core.json.UTF8StreamJsonParser._reportInvalidChar(UTF8StreamJsonParser.java:3538) at com.fasterxml.jackson.core.json.UTF8StreamJsonParser._finishString2(UTF8StreamJsonParser.java:2543) at com.fasterxml.jackson.core.json.UTF8StreamJsonParser._finishAndReturnString(UTF8StreamJsonParser.java:2469) at com.fasterxml.jackson.core.json.UTF8StreamJsonParser.getText(UTF8StreamJsonParser.java:315) at com.fasterxml.jackson.databind.deser.std.StringDeserializer.deserialize(StringDeserializer.java:36) at com.fasterxml.jackson.databind.deser.std.StringDeserializer.deserialize(StringDeserializer.java:11) at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:504) at com.fasterxml.jackson.databind.deser.impl.FieldProperty.deserializeAndSet(FieldProperty.java:111) at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:276) ... 84 common frames omitted并将let更改为var。您似乎遇到了一个称为Temporal Dead Zone的问题（如Mozilla所述）

有关它的更多信息，请点击此处。 https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/let

let

Answer 2

function getChildrenRecursively(parent) {
  const children = getChildren(parent);
  const arrReturn = children.map(
      (child, index) => ({
          id: parent + "_" + index + "_" + child,
          items: getChildrenRecursively(child),
      }));
  return arrReturn;     
}

function getChildren(parentId) {
  switch (parentId) {
     case 1: return [2, 3];
     case 2: return [4];
     case 3: return [5, 6];
     default: return [];
  }
}

IMO还存在一些问题。 getChrildrenRecursively并没有真正得到孩子，而是建造了一棵树。通过一次调整，它将包括根：

function getTree(parent) {
  function createNode(id, index = 0) {
      return {
          id: parent + "_" + index + "_" + id,
          items: getChildren(id).map(createNode);
      };
  }
  return createNode(parent);
}
console.log(getTree(1).items);

递归JS问题

2 个答案: