csv导入导出

一、依赖

         <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-csv</artifactId>
            <version>1.7</version>
        </dependency>

二、工具类

import lombok.extern.slf4j.Slf4j;
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;

import java.io.BufferedWriter;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.nio.charset.StandardCharsets;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

/**
 * CSV文件帮助类
 */
@Slf4j
public class CsvUtils {


    /**
     * 词语分隔符,特殊符号
     */
    public static final String WORDS_SPLITTER = "=_,";


    /**
     * 导出csv文件
     * @param date 数据
     * @return
     */
    public static byte[] exportCSV(List<LinkedHashMap<String, Object>> date) {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        BufferedWriter buffCvsWriter = null;
        try {
            OutputStreamWriter osw = new OutputStreamWriter(out, StandardCharsets.UTF_8);
            osw.write(new String(new byte[] { (byte) 0xEF, (byte) 0xBB,(byte) 0xBF }));
            buffCvsWriter = new BufferedWriter(osw);
            // 将body数据写入表格
            if(date != null){
                for (Iterator<LinkedHashMap<String, Object>> iterator = date.iterator(); iterator.hasNext();) {
                    fillDataToCsvDate(buffCvsWriter, iterator.next());
                    if (iterator.hasNext()) {
                        buffCvsWriter.newLine();
                    }
                }
            }
            // 刷新缓冲
            buffCvsWriter.flush();
        } catch (IOException e) {
           log.error("缓存区异常：{}",e);
        } finally {
            // 释放资源
            if (buffCvsWriter != null) {
                try {
                    buffCvsWriter.close();
                } catch (IOException e) {
                    log.error("释放资源失败：{}",e);
                }
            }
        }
        return out.toByteArray();
    }

    public static byte[] exportXlsx(Map<String, List<LinkedHashMap<String, Object>>> tableData) {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        try {
            HSSFWorkbook workbook = new HSSFWorkbook();
            // 创建多个sheet
            for (Map.Entry<String, List<LinkedHashMap<String, Object>>> entry : tableData.entrySet()) {
                fillDataToXlsx(workbook.createSheet(entry.getKey()), entry.getValue());
            }
            workbook.write(out);
        } catch (IOException e) {
           log.error("生成Excel失败：{}",e);
        }
        return out.toByteArray();
    }

    /**
     * 将linkedHashMap中的数据，写入xlsx表格中
     *
     * @param sheet
     * @param data
     */
    private static void fillDataToXlsx(HSSFSheet sheet, List<LinkedHashMap<String, Object>> data) {
        HSSFRow currRow;
        HSSFCell cell;
        LinkedHashMap row;
        Map.Entry propertyEntry;
        int rowIndex = 0;
        int cellIndex = 0;
        for (Iterator<LinkedHashMap<String, Object>> iterator = data.iterator(); iterator.hasNext(); ) {
            row = iterator.next();
            currRow = sheet.createRow(rowIndex++);
            for (Iterator<Map.Entry> propertyIterator = row.entrySet().iterator(); propertyIterator.hasNext(); ) {
                propertyEntry = propertyIterator.next();
                if (propertyIterator.hasNext()) {
                    String value = String.valueOf(propertyEntry.getValue());
                    cell = currRow.createCell(cellIndex++);
                    cell.setCellValue(value);
                } else {
                    String value = String.valueOf(propertyEntry.getValue());
                    cell = currRow.createCell(cellIndex++);
                    cell.setCellValue(value);
                    break;
                }
            }
            if (iterator.hasNext()) {
                cellIndex = 0;
            }
        }
    }

    public static String getValue(String[] item,int index){
        if(item.length > index){
            String value = item[index];
            return value;
        }
        return "";
    }

    private static String getFileSuffix(String originalFilename) {
        if (org.apache.commons.lang3.StringUtils.isNotBlank(originalFilename)) {
            int dotIndex = originalFilename.lastIndexOf('.');
            if (dotIndex > -1) {
                return originalFilename.substring(dotIndex).trim();
            }
        }
        return "";
    }

    private static void fillDataToCsvDate(BufferedWriter buffCvsWriter, LinkedHashMap row) throws IOException {
        Map.Entry propertyEntry;
        for (Iterator<Map.Entry> propertyIterator = row.entrySet().iterator(); propertyIterator.hasNext();) {
            propertyEntry = propertyIterator.next();
            buffCvsWriter.write("\"" + propertyEntry.getValue().toString() + "\"");
            if (propertyIterator.hasNext()) {
                buffCvsWriter.write(WORDS_SPLITTER);
            }
        }
    }
   
}

三、导出

        File file = new File(filePath);
        if(!new File(filePath).exists()){
            new File(filePath).mkdirs();
        }
        try (FileOutputStream stream = new FileOutputStream(file)) {
            LinkedHashMap<String, Object> header = new LinkedHashMap<>();
            header.put("1", "测试1");
            header.put("2", "测试2");
            List<LinkedHashMap<String, Object>> date = new ArrayList<>();
            date.add(header);
            date.addAll(data);
            stream.write(CsvUtils.exportCSV(date));
        } catch (Exception e) {
            log.error("导出失败",e);
        }

四、导入

        List<String> resultB = new ArrayList();
        int i = 0;
        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(in, StandardCharsets.UTF_8));
            String line = reader.readLine();
            if(line == null){
                return OperationResult.fail("文件头不正确，请按照模板导入！");
            }
            List<String> listA = Arrays.asList(line.split(WORDS_SPLITTER));
            listA.stream().forEach(e-> airyList.add(e.substring(1,e.length()-1)));
            while (true) {
                String lines = reader.readLine();
                if (lines == null) {
                    break;
                }
                // 第一行标题不转换
                if (i >= 0) {
                    String[] item = lines.split(WORDS_SPLITTER);
                    String value = getValue(item, 0);
                    if(StringUtils.isEmpty(value) || "\"\"".equals(value)){
                        break;
                    }
                    list.add(value);
                }
                i++;
            }
        } catch (Exception e) {
            log.error("解析文件失败：{}, 第{}条数据",e, i);
            return OperationResult.fail("解析文件失败！");
        }