[英]SpringBoot, how to access a map from another class?
我有一個此類,該類允許我注冊數據存儲庫以在另一個組件中訪問。
總體思路是,我有一張地圖,並且可以通過關聯的鍵(只是一個字符串)引用每個單獨的存儲庫。
通過調試,當我希望將其作為對每個JpaRepository的引用時,映射中的值似乎為null,這使我相信該布線無法正常工作。
1)我想使地圖靜態化,但仍然可以毫無問題地訪問存儲庫
2)這實際上在關聯的使用者類中不起作用,我的spring-boot服務器無法從NPE啟動。
@Autowired private DataLoaderRegistrar loaderConstants;
以上是我認為應如何宣布? 希望這可以改變,如果它變成靜態的。
我正在遍歷類中的對象,並使用以下方法調用此DataLoaderRegistrar
類:
以下每個方面的簡要說明:
我要遍歷幾種類型,這將獲取每個關聯數據類型的類名(這是映射中的鍵),然后在關聯的JPA存儲庫上調用save方法。
.forEach(
dataType -> {
loaderConstants.getRepo(dataType.toString()).save(dataType);
});
@Component
public class DataLoaderRegistrar {
/** Auto wired all {@link JpaRepository} references here to support storing test data in DB */
@Autowired public UserRepository userRepo;
@Autowired public GoalRepository goalRepo;
/**
* All registered entities can go here with an association to their repository as the value
* Examples can be seen in {@link com.habicus.core.data GoalRepository} as well as {@link
* com.habicus.core.entities.Goal}
*/
private Map<String, JpaRepository> reposByName =
new HashMap<String, JpaRepository>() {
{
put(User.class.getSimpleName(), userRepo);
put(Goal.class.getSimpleName(), userRepo);
}
};
public DataLoaderRegistrar() {}
/**
* Returns the requested repository that is stored in the
*
* @param className
* @return {@link JpaRepository} that is associated with a particular class name
*/
public JpaRepository getRepo(String className) {
return reposByName.get(className);
}
/**
* Method returns a {@link Map} which has a {@link String} as the key and an associated {@link
* JpaRepository} as the value, which represents a CRUD repository for all supported data types in
* our system
*/
public Map<String, JpaRepository> retrieveAllDataRepositories() {
return reposByName;
}
}
* Exception is:
org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':bootRun'.
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:103)
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:73)
at org.gradle.api.internal.tasks.execution.OutputDirectoryCreatingTaskExecuter.execute(OutputDirectoryCreatingTaskExecuter.java:51)
at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:59)
at org.gradle.api.internal.tasks.execution.ResolveTaskOutputCachingStateExecuter.execute(ResolveTaskOutputCachingStateExecuter.java:54)
at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:59)
at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:101)
at org.gradle.api.internal.tasks.execution.FinalizeInputFilePropertiesTaskExecuter.execute(FinalizeInputFilePropertiesTaskExecuter.java:44)
at org.gradle.api.internal.tasks.execution.CleanupStaleOutputsExecuter.execute(CleanupStaleOutputsExecuter.java:91)
at org.gradle.api.internal.tasks.execution.ResolveTaskArtifactStateTaskExecuter.execute(ResolveTaskArtifactStateTaskExecuter.java:62)
at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:59)
at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:54)
at org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter.execute(ExecuteAtMostOnceTaskExecuter.java:43)
at org.gradle.api.internal.tasks.execution.CatchExceptionTaskExecuter.execute(CatchExceptionTaskExecuter.java:34)
at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker$1.run(DefaultTaskGraphExecuter.java:256)
at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:199)
at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)
at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:249)
at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:238)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.processTask(DefaultTaskPlanExecutor.java:123)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.access$200(DefaultTaskPlanExecutor.java:79)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker$1.execute(DefaultTaskPlanExecutor.java:104)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker$1.execute(DefaultTaskPlanExecutor.java:98)
at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.execute(DefaultTaskExecutionPlan.java:663)
at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.executeWithTask(DefaultTaskExecutionPlan.java:597)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.run(DefaultTaskPlanExecutor.java:98)
at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:63)
at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:46)
at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
Caused by: org.gradle.process.internal.ExecException: Process 'command '/Library/Java/JavaVirtualMachines/jdk1.8.0_151.jdk/Contents/Home/bin/java'' finished with non-zero exit value 1
at org.gradle.process.internal.DefaultExecHandle$ExecResultImpl.assertNormalExitValue(DefaultExecHandle.java:389)
at org.gradle.process.internal.DefaultJavaExecAction.execute(DefaultJavaExecAction.java:36)
at org.gradle.api.tasks.JavaExec.exec(JavaExec.java:75)
at org.springframework.boot.gradle.tasks.run.BootRun.exec(BootRun.java:51)
at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:73)
at org.gradle.api.internal.project.taskfactory.StandardTaskAction.doExecute(StandardTaskAction.java:46)
at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:39)
at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:26)
at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(AbstractTask.java:788)
at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(AbstractTask.java:755)
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$1.run(ExecuteActionsTaskExecuter.java:124)
at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:199)
at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:113)
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:95)
... 30 more
java.lang.NullPointerException: null
at com.habicus.repository.Loader.lambda$loadTestContainers$0(Loader.java:155) ~[main/:na]
at java.util.ArrayList.forEach(ArrayList.java:1255) ~[na:1.8.0_151]
at com.habicus.repository.Loader.loadTestContainers(Loader.java:153) ~[main/:na]
at com.habicus.repository.Loader.onApplicationEvent(Loader.java:120) ~[main/:na]
at com.habicus.repository.Loader.onApplicationEvent(Loader.java:49) ~[main/:na]
at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172) ~[spring-context-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165) ~[spring-context-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139) ~[spring-context-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:400) ~[spring-context-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:354) ~[spring-context-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at org.springframework.boot.context.event.EventPublishingRunListener.running(EventPublishingRunListener.java:103) ~[spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at org.springframework.boot.SpringApplicationRunListeners.running(SpringApplicationRunListeners.java:78) ~[spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:343) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1255) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1243) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at com.habicus.CoreApplication.main(CoreApplication.java:29) [main/:na]
Arrays.stream(resources)
.map(this::ingestFromFile)
.collect(Collectors.toList())
.stream()
.map(Container.class::cast)
.map(Container::getAll)
.flatMap(Collection::stream)
.collect(Collectors.toList())
.forEach(
dataType -> {
loaderConstants.getRepo(dataType.toString()).save(dataType);
LOGGER.log(Level.INFO, "Saved: " + dataType);
});
}
當Spring實例化DataLoaderRegistrar
時會初始化reposByName
但是此時repos已被動態注入。 若要解決它,您可以使用@PostConstruct
批注來批注某些方法。 注入所有依賴項后,Spring將調用此方法。
Component
public class DataLoaderRegistrar {
@Autowired public UserRepository userRepo;
@Autowired public GoalRepository goalRepo;
@PostConstruct
public void registerRepos() {
reposByName = new HashMap<String, JpaRepository>();
reposByName.put(User.class.getSimpleName(), userRepo);
reposByName.put(Goal.class.getSimpleName(), userRepo);
}
...
}
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