逐列读取 CSV 文件 [英] Read CSV file column by column

问题描述

我想从多列 csv 文件中读取特定列，并使用 Java 在其他 csv 文件中打印这些列.请问有什么帮助吗?以下是我逐行打印每个令牌的代码..但我希望只打印多列 csv 中的几列.

I want to read specific columns from a multi column csv file and print those columns in other csv file using Java. Any help please? Following is my code to print each token line by line..But I am looking to print only few columns out of the multi column csv.

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;
import java.util.StringTokenizer;

public class ParseCSV {

    public static void main(String[] args) {

        try
        {

            //csv file containing data
            String strFile = "C:\Users\rsaluja\CMS_Evaluation\Drupal_12_08_27.csv";

            //create BufferedReader to read csv file
            BufferedReader br = new BufferedReader( new FileReader(strFile));
            String strLine = "";
            StringTokenizer st = null;
            int lineNumber = 0, tokenNumber = 0;

            //read comma separated file line by line
            while( (strLine = br.readLine()) != null)
            {
                lineNumber++;

                //break comma separated line using ","
                st = new StringTokenizer(strLine, ",");

                while(st.hasMoreTokens())
                {
                //display csv values
                tokenNumber++;
                System.out.println("Line # " + lineNumber +
                                ", Token # " + tokenNumber
                                + ", Token : "+ st.nextToken());


                            System.out.println(cols[4]);

推荐答案

你应该使用优秀的 OpenCSV读取和写入 CSV 文件.要调整您的示例以使用该库，它看起来像这样:

You should use the excellent OpenCSV for reading and writing CSV files. To adapt your example to use the library it would look like this:

public class ParseCSV {
  public static void main(String[] args) {
    try {
      //csv file containing data
      String strFile = "C:/Users/rsaluja/CMS_Evaluation/Drupal_12_08_27.csv";
      CSVReader reader = new CSVReader(new FileReader(strFile));
      String [] nextLine;
      int lineNumber = 0;
      while ((nextLine = reader.readNext()) != null) {
        lineNumber++;
        System.out.println("Line # " + lineNumber);

        // nextLine[] is an array of values from the line
        System.out.println(nextLine[4] + "etc...");
      }
    }
  }
}

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