使用Apache POI将多个csv复制到java中的xls文件

Question

我在这个博客和IT领域都很新.我在将csv文件中的值复制到现有xls文件时遇到问题.我正在使用Apache POI.我有两个csv文件和两个现有的xls文件output0.xls和output1.xls用于相应的csv文件.我正在尝试将第1个csv文件中的值复制到output0.xls,将第2个csv文件复制到output1.xls.I ve为此制作了代码.它运行正常

但问题是,从第二个csv文件中将第一个csv文件的值放到output0.xls后,我试图将值复制到output1.xls,它会将第一个csv文件的值附加到第二个csv文件,将两个文件的值写入output1.xls.

我无法找出主要问题在哪里.请任何人尽快帮助我......否则我将面临一个大问题.

代码使用的是

import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;

public class Demo {

    // FileOutputStream fileOut=null;
     //FileInputStream fis=null;

public static void main(String[] args) throws IOException {

        /*File f=new File("c:\\");
        // return boolean-->System.out.println(f.isDirectory());
        File[]files=f.listFiles();*/
    String thisline;
    ArrayList<String> al = null;
    ArrayList<ArrayList<String>> arlist = new ArrayList<ArrayList<String>>();

    String libRoot=new File(".").getAbsolutePath();       
    libRoot=libRoot.replaceAll("\\\\", "/");
    File f=new File(libRoot+"/result");
    FilenameFilter filter = new FilenameFilter()
    {
        @Override public boolean accept(File dir, String name)
        {
            return name.endsWith(".csv");
        }
    };


    File file[]=f.listFiles(filter);


    for(int r=0;r<file.length;r++){
        File currentFile=file[r];


        FileInputStream fis = new FileInputStream(currentFile);
        //DataInputStream myInput = new DataInputStream(fis);
        BufferedReader br = new BufferedReader(new InputStreamReader(fis));
        while ((thisline = br.readLine()) != null) {
            al = new ArrayList<String>();
            String strar[] = thisline.split(",");

            for (int j = 0; j < strar.length; j++) {


                al.add(strar[j]);
            }

            arlist.add(al);
            //i++;

        } 

        fis.close();


            HSSFWorkbook hwb = new HSSFWorkbook();
            HSSFSheet sheet = hwb.createSheet("new sheet"+r);

            for (int k = 0; k < arlist.size(); k++) {
                ArrayList<String> ardata = (ArrayList<String>) arlist.get(k);
                HSSFRow row = sheet.createRow((short) k);

                for (int p = 0; p < ardata.size(); p++) {
                    //System.out.print(ardata.get(p));
                    HSSFCell cell = row.createCell((short) p);
                    cell.setCellValue(ardata.get(p).toString());
                }
            }



            FileOutputStream fileOut = new FileOutputStream(libRoot+"/result/output"+r+".xls");
            hwb.write(fileOut);
            fileOut.flush();
            fileOut.close();
            br.close();

            //hwb=null;
            }


            }


   }

Answer 1

您的代码的简单问题是您没有重新初始化arlist.

因此,CSV1和CSV2的数据都被复制到output1.xls中.

你需要添加arlist.clear(); 如下面的代码中所述.

更新代码为:

for(int r=0;r<file.length;r++){
    arlist.clear();
    File currentFile=file[r];


    FileInputStream fis = new FileInputStream(currentFile);
    //DataInputStream myInput = new DataInputStream(fis);
    BufferedReader br = new BufferedReader(new InputStreamReader(fis));
    while ((thisline = br.readLine()) != null) {
        al = new ArrayList<String>();
        String strar[] = thisline.split(",");

        for (int j = 0; j < strar.length; j++) {


            al.add(strar[j]);
        }

        arlist.add(al);
        //i++;

    } 

    fis.close();


        HSSFWorkbook hwb = new HSSFWorkbook();
        HSSFSheet sheet = hwb.createSheet("new sheet"+r);

        for (int k = 0; k < arlist.size(); k++) {
            ArrayList<String> ardata = (ArrayList<String>) arlist.get(k);
            HSSFRow row = sheet.createRow((short) k);

            for (int p = 0; p < ardata.size(); p++) {
                //System.out.print(ardata.get(p));
                HSSFCell cell = row.createCell((short) p);
                cell.setCellValue(ardata.get(p).toString());
            }
        }



        FileOutputStream fileOut = new FileOutputStream(libRoot+"/result/output"+r+".xls");
        hwb.write(fileOut);
        fileOut.flush();
        fileOut.close();
        br.close();

        //hwb=null;
        }


        }

希望这可以帮助.