忽略Apache Commons CSV / OpenCSV中引号括起来的字段中的分隔符？

Question

我必须解析一个 csv 文件，该文件的字段如下所示：

("FOO, BAR BAZ", 42)

并产生两个字段：

FOO, BAR BAZ  
42

我不确定如何使用 Apache Commons CSV 或 OpenCSV 简洁地做到这一点，所以我正在寻找一些指导。可能只是我不完全理解org.apache.commons.csv.CSVFormat 属性“quoteChar”which is touched on in the documentation，但在我能找到的任何地方都没有清楚地解释过。如果是这样，如果您能向我指出有关该功能的更好文档，那将非常有帮助。

这是一个简短的示例，显示了我的问题以及我尝试过的方法和结果：

        String test = "(\"FOO, BAR BAZ\", 42)";
        int numTries = 5;
        CSVParser[] tries = new CSVParser[numTries];
        tries[0] = CSVParser.parse(line, CSVFormat.DEFAULT.withRecordSeparator("\n"));//BAR BAZ"
        tries[1] = CSVParser.parse(line, CSVFormat.DEFAULT.withQuote('"'));//BAR BAZ"
        tries[2] = CSVParser.parse(line, CSVFormat.DEFAULT.withQuote(null));//BAR BAZ"
        tries[3] = CSVParser.parse(line, CSVFormat.DEFAULT.withQuote('"').withQuoteMode(QuoteMode.NON_NUMERIC));//BAR BAZ"
        tries[4] = CSVParser.parse(line, CSVFormat.DEFAULT.withRecordSeparator(")\n("));//BAR BAZ"

        for(int i = 0; i < numTries; i++){
            CSVRecord record = tries[i].getRecords().get(0);
            System.out.println(record.get(1));//.equals("42"));
        }  

请注意，如果您从输入中排除括号，它会正常工作。

Answer 1

可以使用OpenCSV的CSVReader读取数据，获取数据元素如下图：

public static void main(String[] args) {
    try(FileReader fr = new FileReader(new File("C:\\Sample.txt"));
                CSVReader csvReader = new CSVReader(fr);) {
            String[] data = csvReader.readNext();
            for(String data1 : data) {
                System.out.println(data1);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

Answer 2

您可以使用 opencsv 实现此目的，如下所示：

import com.opencsv.CSVReader;
import java.io.FileReader;
import java.io.IOException;

public class NewClass1 {
    public static void main(String[] args) throws IOException {
        String fileName = "C:\\yourFile.csv";
        String [] nextLine;
        // use the three arg constructor to tell the reader which delimiter you have in your file(2nd arg : here ',')                                                          
        // you can change this to '\t' if you have tab separeted file or ';' or ':' ... whatever your delimiter is
        // (3rd arg) '"' if your fields are double quoted or '\'' if single quoted or no 3rd arg if the fields are not quoted
        CSVReader reader = new CSVReader(new FileReader(fileName), ',' ,'"');
        // nextLine[] is an array of values from the line
        // each line represented by String[], and each field as an element of the array
        while ((nextLine = reader.readNext()) != null) {        
            System.out.println("nextLine[0]: " +nextLine[0]);
            System.out.println("nextLine[1]: " +nextLine[1]);
        }
    }
}

Answer 3

对我来说，commons-csv 的默认格式对于格式正确的 CSV 消息是正确的：

    Reader in = new StringReader("\"FOO, BAR BAZ\", 42");
    Iterable<CSVRecord> records = CSVFormat.DEFAULT.parse(in);
    for (CSVRecord record : records) {
        for(int i = 0;i < record.size();i++) {
            System.out.println("At " + i + ": " + record.get(i));
        }
    }

导致：

At 0: FOO, BAR BAZ
At 1:  42

对于特殊格式的行，您可能需要做更多处理，顶部删除那些括号：

    BufferedReader lineReader = new BufferedReader(
            new StringReader("(\"FOO, BAR BAZ\", 42)\n(\"FOO, BAR FOO\", 44)"));

    while(true) {
        String line = lineReader.readLine();
        if (line == null) {
            break;
        }

        String adjustedLine = line.substring(1, line.length() - 1);
        records = CSVFormat.DEFAULT.parse(new StringReader(adjustedLine));
        for (CSVRecord record : records) {
            for (int i = 0; i < record.size(); i++) {
                System.out.println("At " + i + ": " + record.get(i));
            }
        }
    }