使用openCSV用新值更新一行

Question

我需要使用openCSV实用程序用新值更新一行。例如，我有以下CSV文件，我需要将包含TestdminUsername1和TestdminUsername2的行分别更新为TestdminUsername1,Fail,Errors Found和TestdminUsername2,Fail,Errors Found。

TestdminUsername1,Pass,No Error
TestAdminUsername2,Pass,No Error
TestAdminUsername3,Pass,No Error
TestAdminUsername4,Pass,No Error
TestAdminUsername5,Pass,No Error
TestAdminUsername6,Pass,No Error
TestAdminUsername7,Pass,No Error
TestAdminUsername8,Pass,No Error
TestAdminUsername9,Pass,No Error
TestAdminUsername10,Pass,No Error

下面是我使用的一段代码:

import java.io.FileReader;
import java.io.FileWriter;
import java.util.Arrays;
import com.opencsv.CSVReader;
import com.opencsv.CSVWriter;
public class AppendToCSVExample
{
    @SuppressWarnings("resource")
    public static void main(String[] args) throws Exception
   {
      String csv = "D:\data2.csv";
      CSVWriter writer = new CSVWriter(new FileWriter(csv, true));
      String [] record1 = "TestdminUsername1,Pass,No Error".split(",");
      String [] record2 = "TestAdminUsername2,Pass,No Error".split(",");
      String [] record3 = "TestAdminUsername3,Pass,No Error".split(",");
      String [] record4 = "TestAdminUsername4,Pass,No Error".split(",");
      String [] record5 = "TestAdminUsername5,Pass,No Error".split(",");
      String [] record6 = "TestAdminUsername6,Pass,No Error".split(",");
      String [] record7 = "TestAdminUsername7,Pass,No Error".split(",");
      String [] record8 = "TestAdminUsername8,Pass,No Error".split(",");
      String [] record9 = "TestAdminUsername9,Pass,No Error".split(",");
      String [] record10 = "TestAdminUsername10,Pass,No Error".split(",");
      writer.writeNext(record1);
      writer.writeNext(record2);
      writer.writeNext(record3);
      writer.writeNext(record4);
      writer.writeNext(record5);
      writer.writeNext(record6);
      writer.writeNext(record7);
      writer.writeNext(record8);
      writer.writeNext(record9);
      writer.writeNext(record10);
      writer.close();
      CSVReader reader = new CSVReader(new FileReader("D:\data1.csv"), ',' , '"' , 1);
      String[] nextLine;
      while ((nextLine = reader.readNext()) != null) {
          if (nextLine != null) {
         //Verifying the read data here
         System.out.println(Arrays.toString(nextLine));
         String[] parts = Arrays.toString(nextLine).split(",");
         if (parts[0].toString().contains("TestdminUsername1")) {
             String [] recordTest = "TestdminUsername1, Fail, Errors found".split(",");
              //Which method in openCSV needs to be used to update recordTest value in the File data2.csv
             ;
         }
      }
    }
  }
}

Answer 1

我个人建议您打开第二个CSVWriter到一个新文件(data3.csv)，当您从data1读取数据时，您写入data3更改需要修改的数据。这样，如果由于某种原因出现故障，您仍然拥有原始文件。最后，如果您只想要一个文件，您可以删除data1并将data3.csv重命名为data1.csv。

之前有一个问题，有人试图同时读取和写入同一个文件(从CSV文件中读取并使用java中的openCSV写入新的CSV文件)，但我再次建议不要这样做，以防出现错误。