Question

我需要将行号放入FieldSet Mapper中。我怎么能这样做？

我想将lineNumber用作Mapper生成的结果对象的字段。

<beans:bean id="fileReader" class="org.springframework.batch.item.file.FlatFileItemReader" scope="step">
    <beans:property name="resource" 
        value="file:${batch.source}"/>
    <beans:property name="lineMapper">
        <beans:bean class="org.springframework.batch.item.file.mapping.DefaultLineMapper">
            <beans:property name="lineTokenizer">
                <beans:bean class="org.springframework.batch.item.file.transform.DelimitedLineTokenizer">
                    <beans:property name="delimiter" value="${batch.delimiter}"/>
                    <beans:property name="names" value="${batch.columns}"/>
                </beans:bean>
            </beans:property>

            <beans:property name="fieldSetMapper">
                <beans:bean class="my.batch.mapper.ResourceFieldSetMapper"/>
            </beans:property>
        </beans:bean>
    </beans:property>
</beans:bean>

谢谢。

Answer 1

我意识到我可以通过使用我自己的 LineMapper 覆盖 DefaultLineMapper ，将 lineNumber 值转换为 MyObject 这样：

import org.springframework.batch.item.file.FlatFileParseException;
import org.springframework.batch.item.file.LineMapper;
import org.springframework.batch.item.file.transform.LineTokenizer;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.util.Assert;

import my.model.MyObject;

public class MyLineMapper<T> implements LineMapper<MyObject>, InitializingBean {

    private LineTokenizer tokenizer;

    private ResourceFieldSetMapper fieldSetMapper;

    public MyObject mapLine(String line, int lineNumber) throws Exception {
        try{
            MyObject r = fieldSetMapper.mapFieldSet(tokenizer.tokenize(line));
            // this is the modification
            r.setLineNumber(lineNumber);
            return r;
        }
        catch(Exception ex){
            throw new FlatFileParseException("Parsing error at line: " + lineNumber + 
                    ", input=[" + line + "]", ex, line, lineNumber); 
        }
    }

    public void setLineTokenizer(LineTokenizer tokenizer) {
        this.tokenizer = tokenizer;
    }

    public void setFieldSetMapper(ResourceFieldSetMapper fieldSetMapper) {
        this.fieldSetMapper = fieldSetMapper;
    }

    public void afterPropertiesSet() {
        Assert.notNull(tokenizer, "The LineTokenizer must be set");
        Assert.notNull(fieldSetMapper, "The FieldSetMapper must be set");
    }

}

感谢您的帮助！我希望这对某人有用！

祝福！

Answer 2

我认为您可以使用spEL表达式＃{fileReader.currentItemCount}，但为此目的有SB接口ItemCountAware。

标记界面，指示项目应具有项目计数设置它。通常用于 AbstractItemCountingItemStreamItemReader。

Spring Batch - 在FieldSetMapper上获取行号

2 个答案: