Spring Boot java.lang.IllegalStateException:InputStream已经被读取-如果需要多次读取流,请不要使用InputStreamResource

yqyhoc1h  于 2023-11-17  发布在  Spring
关注(0)|答案(3)|浏览(267)

我试图从aws s3 bucket中读取文件,并将其设置为spring batch reader类中的资源。当我在aws lambda函数上测试应用程序时,我得到了以下错误。Maven有什么建议吗?

Caused by: java.lang.IllegalStateException: InputStream has already been read - do not use InputStreamResource if a stream needs to be read multiple times
    at org.springframework.core.io.InputStreamResource.getInputStream(InputStreamResource.java:97) ~[task/:na]
    at org.springframework.batch.item.file.DefaultBufferedReaderFactory.create(DefaultBufferedReaderFactory.java:34) ~[task/:na]
    at org.springframework.batch.item.file.FlatFileItemReader.doOpen(FlatFileItemReader.java:266) ~[task/:na]
    at org.springframework.batch.item.support.AbstractItemCountingItemStreamItemReader.open(AbstractItemCountingItemStreamItemReader.java:146) ~[task/:na]

Class to read from s3 bucket
@Service
public class S3BucketProcessing {
private static final AmazonS3 s3 = AmazonS3ClientBuilder.standard().build();

public InputStreamResource readFile() throws IOException{

   String bucketName = "mybuckey";
   String key = "File.txt";

   S3Object object = s3.getObject(new GetObjectRequest(bucketName, key));    

   return new InputStreamResource(object.getObjectContent());

}

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Spring批处理读取器类

@Component
public class MyReader extends FlatFileItemReader<MyEntity> {

    MyLineMapper mapper;
    MyTokenizer tokenizer;
    S3BucketProcessing s3BucketProcessing;

    @Autowired
    public MyReader(MyTokenizer tokenizer, MyLineMapper mapper, S3BucketProcessing s3BucketProcessing) throws Exception{
        LOG.info("CardCustomerNotificationReader constructor");
        this.mapper = mapper;
        this.tokenizer = tokenizer;
        this.s3BucketProcessing= s3BucketProcessing;
        this.setResource(s3BucketProcessing.readFile());
        mapper.setLineTokenizer(tokenizer);
        this.setLineMapper(mapper);
    }
}

yc0p9oo0

yc0p9oo01#

文档建议使用ByteArrayResource将内容缓存在内存中,而不是InputStreamResource。
https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/core/io/InputStreamResource.html
只需像这样更改返回部分:

//As suggested by berzerk
byte[] content = IOUtils.toByteArray(object.getObjectContent()); 

//Then
return new ByteArrayResource( content );

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bgibtngc

bgibtngc2#

而不是返回InputStreamResource,你shud返回流的内容可能是byte[]

byte[] content = IOUtils.toByteArray(object.getObjectContent());
return content ;

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zpgglvta

zpgglvta3#

所以我必须将JSON/XML对象作为输出流发送。我使用的是InputStreamResource,得到的错误与OP相同。
这是对我有效的解决方案。

@Override
    public Resource dataExportForFieldExtractorModel() {

        ObjectMapper xmlMapper = new XmlMapper().enable(SerializationFeature.INDENT_OUTPUT);
        byte[] data;
        Resource resource = null;
        try {
            data = xmlMapper.writerWithDefaultPrettyPrinter().writeValueAsBytes(new DataExportResponse());
            resource = new ByteArrayResource(data);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
        return resource;
    }

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由于资源需要为byte[],因此我将resource = new InputStreamResource(new ByteArrayInputStream(data));更改为resource = new ByteArrayResource(data);

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