Spring Batch配置错误

Question

我想配置Spring Batch作业,但是我收到错误,我无法理解是什么意思？

错误:

读者:

import org.springframework.batch.item.ItemReader;

public class MoviesReader implements ItemReader<SearchResponseRO>, StepExecutionListener {

    @Override
    public SearchResponseRO read() throws Exception {
        return new SearchResponseRO();
    }
}

处理器:

import org.springframework.batch.item.ItemProcessor;

public class MoviesProcessor implements ItemProcessor<SearchResponseRO, Movie> {
    @Override
    public Movie process(SearchResponseRO searchResponseRO) throws Exception {
        return new Movie();
    }
}

我需要更改并修复错误？

谢谢.

Answer 1

您需要为操作指定类型chunk.在你的情况下,将是<SearchResponseRO, Movie>.

return stepBuilderFactory.get("downloadStep").<SearchResponseRO, Movie>chunk(10)
  .reader(reader)
  .processor(processor)
  .....

没有类型,它默认为<Object, Object>:

stepBuilderFactory.get("test").chunk(10)
        .reader(new ItemReader<Object>() {
            @Override
            public Object read() throws Exception, UnexpectedInputException, ParseException, NonTransientResourceException {
                return null;
            }
        })
        .processor(new ItemProcessor<Object, Object>() {
            @Override
            public Object process(Object o) throws Exception {
                return null;
            }
        })
        .writer(new ItemWriter<Object>() {
            @Override
            public void write(List<?> list) throws Exception {

            }
        })
        .build();

如果你看一下chunk方法的定义,它接受一个int,但返回SimpleStepBuilder<I, O>.因为没有办法实际提供类型I和O,你必须基本上将它们转换为你想要的值.我相信.<Type>语法只是在链接调用时直接转换的方便,所以以下两件事应该是相同的:

public void castGenericReturnType() {
    System.out.println(this.<Integer>genericReturn(1));
    System.out.println((Integer) genericReturn(1));
}

public <I> I genericReturn(Object objectToCast) {
    return (I) objectToCast;
}