Question

我有一个java代码，我在读取csv文件时读取csv文件中的String。我从现有文件创建一个新的csv文件，有2-3列，我可以期待我正在寻找的字符串变量。

以下是我的csv文件

IP,IP2,ID,PID,Abbr
"1.0.0.0","1.0.0.255","16777216","16777471","AU"
"1.0.1.0","1.0.3.255","16777472","CN","16778239"
"1.0.4.0","1.0.7.255","16778240","16779263","AU"
"1.0.8.0","1.0.15.255","16779264","16781311","CN"
"1.0.16.0","1.0.31.255","16781312","16785407","JP"
"1.0.32.0","1.0.63.255","16785408","16793599","CN"
"1.0.64.0","1.0.127.255","16793600","AU","16809983"
"1.0.128.0","1.0.255.255","16842751","AU","16809984"

用于阅读的Java代码

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

import au.com.bytecode.opencsv.CSVWriter;


public class CSVFileReader {

  public static void main(String[] args) {

    CSVFileReader obj = new CSVFileReader();
    obj.run();

  }

  public void run() {

//String csvFile = "whois.csv";
String csvFile="whois.csv";
    BufferedReader br = null;
    String line = "";
    String cvsSplitBy = ",";
    String sFileName="whois2.csv";

    try {
        FileWriter writer = new FileWriter(sFileName); // NOT creating a new FileWriter each time you are writing a line
        br = new BufferedReader(new FileReader(csvFile));
        while ((line = br.readLine()) != null) {

                // use comma as separator
            String[] country = line.split(cvsSplitBy);
                if(line.contains("AU"))
                {

                    //writer.append(country[4]);
                    writer.write(country[4]);
                    writer.write(",");
                    writer.write(country[3]);
                    writer.write(",");





            System.out.println("Country [code= " + country[2] 
                                 + " , name=" + country[5] + "]");
                }
                else
                {
                    writer.write("");
                    writer.write(",");
                    writer.write("");
                    writer.write(",");
                    writer.write("");
                    writer.append('\n');


            System.out.println("");
                }


        }
        writer.flush();
        writer.close();

    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    } finally {

        if (br != null) {

            try {
                br.close();
            }

            catch (IOException e) {
                e.printStackTrace();
            }

        }


    }

    System.out.println("Done");
  }

}

根据上面的java代码我在上面的字段为AU的whois.csv文件，其中我发现字符串im打印那些列并创建一个新的csv文件。我想要的是当我在比较字符串AU时创建一个新文件使用我的csv内容，我想在原始文件中的新文件althogh中的一列中列出所有AU内容列值，AU字符串值在不同的列中。就像AU字符串存在于第一行和最后两行，这个csv文件将来可能会更长。但是我不确定该字符串是否为此字符串。所以我在新的csv文件中插入可疑行。但是在新的csv文件中，我只想要一个包含所有AU字符串列值的列，无论它们是在第三列，第四列还是任何其他列中，AU将仅出现在csv文件的每一行中的一列中... 请指导一下......

Answer 1

将此代码放在您希望它开始写出连接字段值的位置，它将在一列中写入包含AU的当前行的所有字段值。

for (String field : country)
    if(line.contains("AU"))
        writer.write(field);

检查字符串并在读取现有csv文件时使用java创建csv

1 个答案: