java - 获取java.lang.ClassCastException:实现ItemProcessor时无法将javax.xml.bind.JAXBElement强制转换为com。[mySchema]。

所以我要创建我的第一个Spring批处理作业。我试图读取xml，操作一些值并将其写出。如果我不实现org.springframework.batch.item.ItemProcessor接口，我的工作似乎是解组XML文档并将其写得很好。一旦实现了接口（为了操作值）需要做的事情，就会收到以下错误。当我检查输出文件时，它输出xml标记，开始的根元素标记，并且没有其他输出。如果在工作的第一步中将对处理器的调用注释掉，则该文件将写出到我的文件目录中。任何帮助将不胜感激，我一直在寻找解决办法，没有任何运气。我的消息针对多个大型xsd进行了验证，因此我将其排除在代码之外。


  2018-05-21 15：58：57.690错误6684 --- [main] o.s.batch.core.step.AbstractStep：在作业importUserJob中执行步骤step1时遇到错误
  java.lang.ClassCastException：无法将javax.xml.bind.JAXBElement强制转换为[mySchema]
      BatchProcessor.process（BatchProcessor.java:1）〜[classes /：na]

public class BatchProcessor implements ItemProcessor<ProdRequest, ProdRequest>{

@Override
public ProdRequest process(ProdRequest arg0) throws Exception {
    //Error still thrown even when I comment out all of the code. Break points in this methoda re never reached.
    return arg0;
}

}

--

@Configuration
@EnableBatchProcessing
public class XMLReaderConfiguration {

@Autowired
public JobBuilderFactory jobBuilderFactory;

@Autowired
public StepBuilderFactory stepBuilderFactory;





@Bean
public BatchProcessor processor() {
    return new BatchProcessor();
}

@Bean(destroyMethod="")
public StaxEventItemReader<ProdRequest> reader(){
    StaxEventItemReader<ProdRequest> reader = new StaxEventItemReader<>();
    reader.setResource(new ClassPathResource("policy.xml"));
    reader.setFragmentRootElementName("ProdRequest");

    Jaxb2Marshaller xmlMarshaller = new Jaxb2Marshaller();

    ObjectFactory objectFactory = new ObjectFactory();


    xmlMarshaller.setClassesToBeBound(new Class[] {
            //all of my object classes (all generated by JAXB) I have added the xmlRootElement attribute to my top level class only.
           });

    xmlMarshaller.setSupportJaxbElementClass(true);



    reader.setUnmarshaller(xmlMarshaller);



    return reader;
}

@Bean(destroyMethod="")
public StaxEventItemWriter<ProdRequest> writer(){
    StaxEventItemWriter<ProdRequest> writer = new StaxEventItemWriter<ProdRequest>();
    String exportFilePath = "C:/Test/springBatchTest.xml";
    writer.setResource(new FileSystemResource(exportFilePath));
    writer.setRootTagName("ProdRequest");

    Jaxb2Marshaller xmlMarshaller = new Jaxb2Marshaller();

    xmlMarshaller.setClassesToBeBound(new Class[] {
            //all of my object classes (all generated by JAXB) I have added the xmlRootElement attribute to my top level class only.
           });

    xmlMarshaller.setSupportJaxbElementClass(true);
    writer.setMarshaller(xmlMarshaller);
    return writer;
}

@Bean
public Step step1(){
    return stepBuilderFactory.get("step1")
            .<ProdRequest, ProdRequest> chunk(10)
            .reader(reader())
            .processor(processor())
            .writer(writer())
            .build();
}


@Bean
public Job importUserJob(){
    return jobBuilderFactory.get("importUserJob")
            .incrementer(new RunIdIncrementer())
            .flow(step1())
            .end()
            .build();
}
}

最佳答案

因此，最终我在spring框架中设置了一个断点，并发现在取消整理我的文档之后，它实际上是返回一个通用的JAXBElement，其中包含了我所期望的文档。当那个JAXBElement被传递给实现Spring ItemProcessor的我的BatchProcessor类时，由于我的类不希望文档位于JAXBElement内部，因此引发了错误。因此，为了解决此问题，我必须将BatchProcessor的参数更改为JAXBElement。我的解决方法如下。我删除了一些公司特定的名称和我的JAXBClasses列表。希望这可以帮助某人。谢谢！

public class BatchProcessor implements ItemProcessor<JAXBElement<ProdRequest> , ProdRequest>{

@Override
public ProdRequest process(JAXBElement<ProdRequest>  jaxbElement) throws Exception {
    ObjectFactory objectFactory = new ObjectFactory();
    JAXBElement<String> code = objectFactory.createProdRequestCode("test");
    CWDocProdRequest doc = jaxbElement.getValue();
    doc.setCode(code);

    return doc;
}

}

    @Configuration
    @EnableBatchProcessing
    public class XMLReaderConfiguration {

@Autowired
public JobBuilderFactory jobBuilderFactory;

@Autowired
public StepBuilderFactory stepBuilderFactory;


@Bean
public BatchCWAutoProcessor processor() {
    return new BatchCWAutoProcessor();
}

@Bean(destroyMethod="")
public StaxEventItemReader <JAXBElement<ProdRequest>> reader(){
    StaxEventItemReader<JAXBElement<ProdRequest>> reader = new StaxEventItemReader<JAXBElement<ProdRequest>>();
    reader.setResource(new ClassPathResource("policy.xml"));
    reader.setFragmentRootElementName("ProdRequest");




    Jaxb2Marshaller xmlMarshaller = new Jaxb2Marshaller();

    ObjectFactory objectFactory = new ObjectFactory();

    xmlMarshaller.setClassesToBeBound(new Class[] {
                    //auto generated JAXB classes
           });

    xmlMarshaller.setSupportJaxbElementClass(true);


    reader.setUnmarshaller(xmlMarshaller);



    return reader;
}

@Bean(destroyMethod="")
public StaxEventItemWriter<ProdRequest> writer(){
    StaxEventItemWriter<ProdRequest> writer = new StaxEventItemWriter<ProdRequest>();
    String exportFilePath = "C:/springBatchTest.xml";
    writer.setResource(new FileSystemResource(exportFilePath));
    writer.setRootTagName("ProdRequest");


    Jaxb2Marshaller xmlMarshaller = new Jaxb2Marshaller();

    xmlMarshaller.setClassesToBeBound(new Class[] {
                //list auto generated JAXB classes here
           });

    xmlMarshaller.setSupportJaxbElementClass(true);

    writer.setMarshaller(xmlMarshaller);
    return writer;
}

@Bean
public Step step1(){
    return stepBuilderFactory.get("step1")
            //.<ProdRequest, ProdRequest> chunk(10)//changed this to the line below
            .<JAXBElement<ProdRequest>, ProdRequest> chunk(10)
            .reader(reader())
            .processor(processor())
            .writer(writer())
            .build();
}


@Bean
public Job importUserJob(){
    return jobBuilderFactory.get("importUserJob")
            .incrementer(new RunIdIncrementer())
            .flow(step1())
            .end()
            .build();
}
    }