如何为不同的记录调用适当的项目处理器？

Question

我有一个包含不同记录的平面文件（页眉、记录和页脚）

HR,...
RD,...
FR,...

项目阅读器

    @Bean
    @StepScope
    public FlatFileItemReader reader(@Value("#{jobParameters['inputFileName']}") String inputFileName) {
        FlatFileItemReader reader = new FlatFileItemReader();
        reader.setResource(new FileSystemResource(inputFileName));
        reader.setLineMapper(patternLineMapper());
        return reader;
    }

    @Bean
    public LineMapper patternLineMapper() {
        PatternMatchingCompositeLineMapper patternLineMapper = new PatternMatchingCompositeLineMapper<>();
        tokenizers = new HashMap<String, LineTokenizer>();
        try {
            tokenizers.put("HR*", headerLineTokenizer());
            tokenizers.put("RD*", recordLineTokenizer());
            tokenizers.put("FR*", footerLineTokenizer());
        } catch (Exception e) {
            e.printStackTrace();
        }
        fieldSetMappers = new HashMap<String, FieldSetMapper>();
        fieldSetMappers.put("HR*", new HeaderFieldSetMapper());
        fieldSetMappers.put("RD*", new RecordFieldSetMapper());
        fieldSetMappers.put("FR*", new FooterFieldSetMapper());
        patternLineMapper.setTokenizers(tokenizers);
        patternLineMapper.setFieldSetMappers(fieldSetMappers);
        return patternLineMapper;
    }

它们运行良好，spring batch为每个记录调用适当的读取器。问题是，当涉及到项处理器时，我希望使用与获取java.lang.ClassCastException相同的方法，因为spring batch尝试将域对象[从读取器返回]映射到java.lang.String

    @Bean
    @StepScope
    public ItemProcessor processor() {

        ClassifierCompositeItemProcessor processor = new ClassifierCompositeItemProcessor();
        PatternMatchingClassifier<ItemProcessor> classifier = new PatternMatchingClassifier<>();
        Map<String, ItemProcessor> patternMap = new HashMap<>();
        patternMap.put("HR*", new HeaderItemProcessor());
        patternMap.put("RD*", new RecordItemProcessor());
        patternMap.put("FR*", new FooterItemProcessor());
        classifier.setPatternMap(patternMap);
        processor.setClassifier(classifier);
        return processor;
    }

Answer 1

问题是在ClassifierCompositeItemProcessor中使用的分类器基于字符串模式而不是类型。真正应该发生的事情是：

读取器根据输入模式返回特定类型的项，类似于：

• hr*->hrtype
• rd*->rdtype
• fr*->frtype

    Map<Object, ItemProcessor> patternMap = new HashMap<>();
    patternMap.put(HRType.class, new HeaderItemProcessor());
    patternMap.put(RDType.class, new RecordItemProcessor());
    patternMap.put(FRType.class, new FooterItemProcessor());

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