java可读取ansi与utf8的csv文件工具类

import lombok.extern.slf4j.Slf4j;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

@Slf4j
public class CsvUtil {
    
    

    /**
     * 读取csv文件
     * @param fileName
     * @param delimiter
     * @param isAnsi 是否为windows的ansi格式，就是在windows上新建并用记事本编辑的，可以在“文件--另存为”，对话框最下面看编码
     * @return
     */
    public static List<List<Object>> getData(String fileName, String delimiter, boolean isAnsi){
    
    
        List<List<Object>> csvData = new ArrayList<>();
        try {
    
    
            Path filePath = Paths.get(fileName);
            Charset fileCharset;
            if (!isAnsi){
    
    
                fileCharset = StandardCharsets.UTF_8;
            }else{
    
    
                fileCharset = Charset.forName("CP1252");
            }
            Files.lines(filePath, fileCharset).forEach(s->{
    
    
                if(s == null || s.length() ==0){
    
    
                    csvData.add(null);
                    return;
                }
                List<Object> lineData = new ArrayList<>();
                csvData.add(lineData);
                if (isAnsi){
    
    
                    try {
    
    
                        s =new String(s.getBytes("CP1252"), "GBK");
                    } catch (UnsupportedEncodingException e) {
    
    
                        e.printStackTrace();
                    }
                }
                // 保留空
                for(String one:s.split(delimiter,-1)){
    
    
                    if (one == null || one.length() == 0){
    
    
                        lineData.add(null);
                    }else{
    
    
                        lineData.add(one);
                    }
                }
            });
        } catch (IOException e) {
    
    
            log.error("error file:{}",fileName);
            e.printStackTrace();
        }
        return csvData;
    }

    public static String toCsv(List<List<Object>> csvData, String delimiter){
    
    
        StringBuilder sb = new StringBuilder();
        for(List<Object> rowData:csvData){
    
    
            if (rowData == null){
    
    
                sb.append(System.lineSeparator());
                continue;
            }
            List<String> oneRow = new ArrayList<>();
            for(Object obj:rowData){
    
    
                if (obj == null || (obj instanceof String && ((String) obj).length() == 0)){
    
    
                    oneRow.add(null);
                    continue;
                }
                if (obj instanceof String){
    
    
                    oneRow.add((String) obj);
                }else if(obj instanceof Integer || obj instanceof Double || obj instanceof Long){
    
    
                    oneRow.add(String.valueOf(obj));
                }else{
    
    
                    oneRow.add(obj.toString());
                }
            }
            String rowStr = oneRow.stream()
                    .map(e->e == null ? "" : e)
                    .collect(Collectors.joining(delimiter));
            sb.append(rowStr).append(System.lineSeparator());
        }
        return sb.toString();
    }

    public static byte[] toAnsi(String content){
    
    
        byte[] data = null;
        if (content == null || content.length() == 0)
            return null;
        try {
    
    
            data = content.getBytes("GBK");
        } catch (UnsupportedEncodingException e) {
    
    
            e.printStackTrace();
        }
        return data;
    }

    public static void toFile(String fileName, byte[] data){
    
    
        if (data == null || data.length == 0)
            return;
        try {
    
    
            FileOutputStream fos = new FileOutputStream(fileName);
            fos.write(data);
            fos.flush();
            fos.close();
        } catch (IOException e) {
    
    
            e.printStackTrace();
        }
    }
}

测试用例

import org.junit.jupiter.api.Test;

import java.util.List;

import static org.junit.jupiter.api.Assertions.*;

class CsvUtilTest {
    
    

    @Test
    void getData() {
    
    
        List<List<Object>> csvData = CsvUtil.getData("one.txt",",",true);
        System.out.println(csvData);
    }


    @Test
    void toCsv() {
    
    
        List<List<Object>> csvData = CsvUtil.getData("one.txt",",",true);
        String csvStr = CsvUtil.toCsv(csvData,",");
//        System.out.println(csvStr);

        CsvUtil.toFile("test.txt",csvStr.getBytes());
        CsvUtil.toFile("test2.txt",CsvUtil.toAnsi(csvStr));
    }
}