如何使用Spring Batch写入Azure Blob？

Question

我正在尝试用Spring批处理将一行csv写入Azure Blob。

自动连接Azure存储:

@Value("${azure.storage.ConnectionString}")
private String connectionString;

@Value("${azure.storage.container.name}")
private String containerName;


@Bean
@StepScope
public FlatFileItemWriter<Pojo> writer(
        @Value("#{stepExecutionContext['marketName']}") String marketName,
        @Value("#{jobParameters['startDate']}") String startDate,
        @Value("#{jobParameters['YYYY-MM']}") String yearMonth
) {
    // Create writer instance
    FlatFileItemWriter<Pojo> writer = new FlatFileItemWriter<>();

    String fullPath = yearMonth + "/" +  marketName + "/" +
            marketName + "_" + startDate;

    BlobContainerClient container = new BlobContainerClientBuilder()
            .connectionString(connectionString)
            .containerName(containerName)
            .buildClient();

    BlobClient blob = container.getBlobClient(fullPath);

    // Set output file location
    writer.setResource((Resource) blob);

    // All job repetitions should "append" to same output file
    writer.setAppendAllowed(true);

    // Name field values sequence based on object properties
    writer.setLineAggregator(new DelimitedLineAggregator<Pojo>() {
        {
            setDelimiter(",");
            setFieldExtractor(new BeanWrapperFieldExtractor<Pojo>() {
                {
                    setNames(new String[] {
                            "market",
                            "epsg",
                            "xbin",
                            "ybin",
                            "latitude",
                            "longitude",
                            "totalDownlinkVol",
                            "totalUplinkVol"
                    });
                }
            });
        }
    });
    return writer;
}

然后我得到错误：

org . spring framework . beans . factory . beancreationexception:创建在类路径资源[com/example/db reader/configuration/batch config . class]中定义的名为“scopedTarget.writer”的bean时出错:通过工厂方法进行的Bean实例化失败；嵌套异常为org . spring framework . beans . bean instantiation exception:无法实例化[org . spring framework . batch . item . file . flat file item Writer]:工厂方法“writer”引发了异常；嵌套异常是Java . lang . classcastexception:com . azure . storage . blob . blob client不能转换为org . spring framework . core . io . resource

Spring抱怨我无法将Blob强制转换为资源。

有没有人知道如何在Spring Batch Writer中指向Azure Blob存储？

谢谢，马库斯。

Answer 1

< code>FlatFileItemWriter需要一个< code > org . spring framework . core . io . resource 来写入数据。如果您使用的API没有实现此接口，则它不能与< code>FlatFileItemWriter一起使用。你需要为Azure提供一个< code>Resource实现，或者寻找一个实现它的库，比如Azure Spring Boot Java Starter Storage client library。