使用 Spring 批处理创建一个 @JobScope @Service 来保存作业的共享内存？

Question

基本上我想要做的是创建一个 @Service 或组件，将一些数据从数据库 table 加载到内存中，该数据库在整个作业执行过程中被引用

package com.squareup.se.bridge.batchworker.components.context;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.base.Strings;
import com.squareup.se.bridge.batchworker.repositories.BridgeBatchJobParametersRepository;
import com.squareup.se.bridge.batchworker.util.JobParameterKeys;
import com.squareup.se.bridge.core.api.services.batchworker.FatalSyncException;
import com.squareup.se.bridge.core.integration.util.logger.JobExecutionLoggerFactory;
import java.io.IOException;
import javax.validation.constraints.NotNull;
import org.slf4j.Logger;
import org.springframework.batch.core.JobExecution;
import org.springframework.batch.core.JobExecutionListener;
import org.springframework.batch.core.configuration.annotation.JobScope;
import org.springframework.stereotype.Component;

@JobScope @Component public class BridgeBatchIntegrationJobContextProvider
    implements JobExecutionListener {
  private Logger logger;
  private ObjectMapper mapper;
  private BridgeBatchJobParametersRepository bridgeBatchJobParametersRepository;
  private BridgeIntegrationJobContext context;

  public BridgeBatchIntegrationJobContextProvider(ObjectMapper mapper,
      BridgeBatchJobParametersRepository bridgeBatchJobParametersRepository) {
    this.mapper = mapper;
    this.bridgeBatchJobParametersRepository = bridgeBatchJobParametersRepository;
  }

  @Override public void beforeJob(JobExecution jobExecution) {
    var jobId = jobExecution.getJobParameters().getString(JobParameterKeys.SYNC_ID);
    this.logger = JobExecutionLoggerFactory.getLogger(
        BridgeBatchIntegrationJobContextProvider.class, jobId);
    this.context = deserializeJobParameters(jobId);
  }

  @NotNull public BridgeIntegrationJobContext get() {
    if (context == null) {
      throw new IllegalStateException("Expected context to exist before calling this method");
    }
    return context;
  }

  @Override public void afterJob(JobExecution jobExecution) { }

  @NotNull private String getParameters(String jobId) {
    var jobParams = bridgeBatchJobParametersRepository.find(jobId);
    if (jobParams == null || jobParams.size() == 0) {
      throw new FatalSyncException(String.format("No job parameters for job `%s` exists", jobId));
    }
    if (jobParams.size() > 1) {
      throw new FatalSyncException(String.format("Multiple parameter entries exist for job `%s`",
          jobId));
    } else if (Strings.isNullOrEmpty(jobParams.get(0).getIntegrationContext())) {
      throw new FatalSyncException(String.format("Job parameters for job `%s` is empty", jobId));
    }
    return jobParams.get(0).getIntegrationContext();
  }

  @NotNull private BridgeIntegrationJobContext deserializeJobParameters(String jobId) {
    try {
      return mapper.readValue(getParameters(jobId),
          BridgeIntegrationJobContext.class);
    } catch (IOException e) {
      //TODO page on this
      logger.info(e.getMessage(), e);
      throw new FatalSyncException(e);
    }
  }
}

我配置了这样的作业：

return jobBuilderFactory.get(CUSTOMERS_BATCH_JOB_NAME)
        .incrementer(new RunIdIncrementer())
        .start(loadFromOriginStep)
        .next(retryFailuresFromOriginStep)
        .listener(bridgeBatchIntegrationJobContextProvider)
        .listener(jobListener)
        .build();

构造函数依赖于其他 bean，包括 jackson 对象映射器和 JPA 存储库。我遇到了一些问题：

构造函数未被 Spring 实例化，因此实例化我要绑定的变量不存在

如果我从组件中删除@JobScope，Spring 构造组件实例。

Answer 1

我没看到你的代码哪里用到了@JobContext，根据你的要求，你不需要它。

如果您想使用侦听器在作业执行上下文中加载一些数据，您可以在 beforeJob 中使用 jobExecution.getExecutionContext().put("key", "value");。

也就是说，不建议在执行上下文中加载大量数据，因为它会在步骤之间持久化。

因此，除非您在执行上下文中加载少量数据，否则您需要找到另一种方法（例如使用单独的缓存，请参阅）。

使用 Spring 批处理创建一个 @JobScope @Service 来保存作业的共享内存？

Create a @JobScope @Service with Spring Batch that holds shared memory for a job?

spring

spring-batch