java是否忽略Apache Commons CSV/OpenCSV中QuotenClosed字段中的分隔符？

Question

我必须解析一个csv文件，该文件包含如下字段：

("FOO, BAR BAZ", 42)

并产生两个字段：

FOO, BAR BAZ  
42

我不知道如何使用ApacheCommonsCSV或OpenCSV简洁地做到这一点，所以我正在寻找一些指导。这可能只是因为我不完全理解org.apache.commons.csv.CSVFormat属性“quoteChar”which is touched on in the documentation，但从未在我能找到的任何地方清楚地解释过。如果是这样的话，如果你能告诉我如何更好地记录这个特性，那将是非常有帮助的

下面是一个简单的例子，展示了我的问题、我的尝试和结果：

        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，如果从输入中排除括号，则效果良好

Answer 1

您可以通过opencsv实现这一点，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 2

您可以使用OpenCSV的CSVReader读取数据并获取数据元素，如下所示：

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 3

对我来说，commons csv的默认格式对于格式正确的csv消息来说是正确的：

    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，您可能需要做更多的处理，删除这些括号：

    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));
            }
        }
    }