java - opencsv CsvToBean的空指针异常

我正在尝试使用openCSV将CSV文件中的所有行转换为Java bean。每行在我的文件中有21列用竖线符号（|）分隔。但是此代码出现空指针异常.csv文件中的行包含空单元格我也无法找出错误所在。任何人都可以帮助我

package com.alu.mdf.testsuite.sure;
import java.io.FileReader;
import java.util.List;
import com.opencsv.CSVParser;
import com.opencsv.CSVReader;
import com.opencsv.bean.ColumnPositionMappingStrategy;
import com.opencsv.bean.CsvToBean;

//import com.alu.mdf.test.common.Person;

    public class CSVExplorer {

        @SuppressWarnings({"rawtypes", "unchecked"})
        public static void main(String[] args) throws Exception
        {
            CsvToBean csv = new CsvToBean();

            String csvFilename = "TestCaseConfigurationFiles/application.csv";
            //CSVReader csvReader = new CSVReader;
            CSVParser csvParser=new CSVParser('|');
            CSVReader reader = new CSVReader(new FileReader(csvFilename),1,csvParser);



            //Set column mapping strategy
            List list = csv.parse(setColumMapping(), reader);

            for (Object object : list) {
                SUREDataBean SUREDataBean = (SUREDataBean) object;
                System.out.println(SUREDataBean);
            }
        }

        @SuppressWarnings({"rawtypes", "unchecked"})
        private static ColumnPositionMappingStrategy setColumMapping() throws Exception
        {
            ColumnPositionMappingStrategy strategy = new ColumnPositionMappingStrategy();
            strategy.setType(SUREDataBean.class);
            //strategy.createBean();
            String[] columns = new String[] {"InputDataStartIdentifier","EntityType","Operation","IncludeId","IdValue","AssociatedResource","SearchQueryForGETRequest/ParametersForPUTRequest","PayloadLocation","TestCaseName","Description","userName","password","InputDataEndIdentifier","ValidationDataStart","ExpectedStatusCode","VerficationParameters","Method","class","Prerequisites","Group","ValidationDataEnd"};
            System.out.println(columns.length);
            strategy.setColumnMapping(columns);
            return strategy;
        }

    }

这是错误堆栈跟踪：


线程“主”中的异常java.lang.RuntimeException：解析CSV时出错！在com.opencsv.bean.CsvToBean.parse（CsvToBean.java:95）在com.opencsv.bean.CsvToBean.parse（CsvToBean.java:75）在com.alu.mdf.testsuite.sure.CSVExplorer.main（CSVExplorer .java：28）由以下原因引起：com处com.opencsv.bean.CsvToBean.processLine（CsvToBean.java:101）处com.opencsv.bean.CsvToBean.processLine（CsvToBean.java:123）处的java.lang.NullPointerException。 opencsv.bean.CsvToBean.parse（CsvToBean.java:91）...

最佳答案

我认为uniVocity-parsers会减少麻烦。它也比OpenCSV更快。要使用它，请首先注释您的bean：

class SUREDataBean {

    @NullString(nulls = { "?", "-" }) // if the value parsed in the quantity column is "?" or "-", it will be replaced by null.
    @Parsed(defaultNullRead = "0") // if a value resolves to null, it will be converted to the String "0".
    private Integer quantity; // The attribute name will be matched against the column header in the file automatically.

    @Trim
    @LowerCase
    @Parsed
    private String comments;
    ...

}

解析：

BeanListProcessor<SUREDataBean> rowProcessor = new BeanListProcessor<SUREDataBean>(SUREDataBean.class);

CsvParserSettings parserSettings = new CsvParserSettings();
settings.getFormat().setDelimiter('|');
parserSettings.setRowProcessor(rowProcessor);
parserSettings.setHeaderExtractionEnabled(true);

CsvParser parser = new CsvParser(parserSettings);

//Parsing is started here.
//this submits all rows parsed from the input to the BeanListProcessor
parser.parse(new FileReader(new File("/examples/bean_test.csv")));

List<SUREDataBean> beans = rowProcessor.getBeans();

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