当标题不在第一行时，Univocity 解析器如何读取 .csv 文件？

Question

当标题不在第一行时，Univocity 解析器如何读取 .csv 文件？

如果 .csv 文件的第一行不是标题，则会出现错误。

代码和堆栈跟踪如下。

任何帮助将不胜感激。

import com.univocity.parsers.csv.CsvParserSettings;
import com.univocity.parsers.common.processor.*;
import com.univocity.parsers.csv.*;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.UnsupportedEncodingException;
import java.lang.IllegalStateException;
import java.lang.String;
import java.util.List;


public class UnivocityParsers {

public Reader getReader(String relativePath) {
    try {
        return new InputStreamReader(this.getClass().getResourceAsStream(relativePath), "Windows-1252");
    } catch (UnsupportedEncodingException e) {
        throw new IllegalStateException("Unable to read input", e);
    }
}


public void columnSelection() {
    RowListProcessor rowProcessor = new RowListProcessor();
    CsvParserSettings parserSettings = new CsvParserSettings();

    parserSettings.setRowProcessor(rowProcessor);
    parserSettings.setHeaderExtractionEnabled(true);
    parserSettings.setLineSeparatorDetectionEnabled(true);
    parserSettings.setSkipEmptyLines(true);

    // Here we select only the columns "Price", "Year" and "Make".
    // The parser just skips the other fields
    parserSettings.selectFields("AUTHOR", "ISBN");

    CsvParser parser = new CsvParser(parserSettings);
    parser.parse(getReader("list2.csv"));

    List<String[]> rows = rowProcessor.getRows();

    String[] strings = rows.get(0);

    System.out.print(strings[0]);

}


public static void main(String arg[]) {

    UnivocityParsers univocityParsers = new UnivocityParsers();

    univocityParsers.columnSelection();


}


}

堆栈跟踪：

    Exception in thread "main" com.univocity.parsers.common.TextParsingException: Error processing input: java.lang.IllegalStateException - Unknown field names: [author, isbn]. Available fields are: [list of books by author - created today]

这是正在解析的文件：

List of books by Author - Created today
"REVIEW_DATE","AUTHOR","ISBN","DISCOUNTED_PRICE"
"1985/01/21","Douglas Adams",0345391802,5.95
"1990/01/12","Douglas Hofstadter",0465026567,9.95
"1998/07/15","Timothy ""The Parser"" Campbell",0968411304,18.99
"1999/12/03","Richard Friedman",0060630353,5.95
"2001/09/19","Karen Armstrong",0345384563,9.95
"2002/06/23","David Jones",0198504691,9.95
"2002/06/23","Julian Jaynes",0618057072,12.50
"2003/09/30","Scott Adams",0740721909,4.95
"2004/10/04","Benjamin Radcliff",0804818088,4.95
"2004/10/04","Randel Helms",0879755725,4.50

Answer 1

从今天开始，您可以在 2.0.0-SNAPSHOT 上执行此操作：

settings.setNumberOfRowsToSkip(1);

在 1.5.6 版本上，您可以这样做以跳过第一行并正确抓取标题：

RowListProcessor rowProcessor = new RowListProcessor(){
        @Override
        public void processStarted(ParsingContext context) {
            super.processStarted(context);
            context.skipLines(1);
        }
    };

如果您的输入文件（如果您可以控制文件的生成方式）通过在要丢弃的行的开头添加#，另一种方法是注释第一行：

#List of books by Author - Created today