万能的导出excel工具

package com.lth.excelexport.excel_export.utils; import com.lth.excelexport.excel_export.annotation.JcExcelName; import lombok.extern.slf4j.Slf4j; import org.apache.commons.io.IOUtils; import org.springframework.util.StringUtils; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.OutputStreamWriter; import java.lang.reflect.Field; import java.lang.reflect.Method; import java.text.SimpleDateFormat; import java.util.*; /** * @ClassName MyCsvFileUtil * @description TODO * @Author JCcco * @Date 2023/4/12 0012 **/ @Slf4j public class MyCsvFileUtil { public static final String FILE_SUFFIX = ".csv"; //分隔符 public static final String CSV_DELIMITER = ","; //文件结尾 public static final String CSV_TAIL = "\r\n"; protected static final String DATE_STR_FILE_NAME = "yyyyMMddHHmmssSSS"; /** * 将字符串转成csv文件 * 字符串写入文件 */ public static void createCsvFile(String savePath, String contextStr) throws IOException { File file = new File(savePath); //创建文件 file.createNewFile(); //创建文件输出流 FileOutputStream fileOutputStream = new FileOutputStream(file); //将指定字节写入此文件输出流 fileOutputStream.write(contextStr.getBytes("gbk")); fileOutputStream.flush(); fileOutputStream.close(); } /** * 写文件 * * @param fileName * @param content */ public static void writeFile(String fileName, String content) { FileOutputStream fos = null; OutputStreamWriter writer = null; try { fos = new FileOutputStream(fileName, true); writer = new OutputStreamWriter(fos, "GBK"); writer.write(content); writer.flush(); } catch (Exception e) { log.error("写文件异常|{}", e); } finally { if (fos != null) { IOUtils.closeQuietly(fos); } if (writer != null) { IOUtils.closeQuietly(writer); } } } /** * 构建文件名称 * @param dataList * @return */ public static String buildCsvFileFileName(List dataList) { return dataList.get(0).getClass().getSimpleName() + new SimpleDateFormat(DATE_STR_FILE_NAME).format(new Date()) + FILE_SUFFIX; } /** * 构建excel 标题行名 * @param dataList * @return */ public static String buildCsvFileTableNames(List dataList) { Map<String, Object> map = toMap(dataList.get(0)); StringBuilder tableNames = new StringBuilder(); for (String key : map.keySet()) { tableNames.append(key).append(MyCsvFileUtil.CSV_DELIMITER); } return tableNames.append(MyCsvFileUtil.CSV_TAIL).toString(); } /** * 构建excel内容 * 转成字符串 * @param dataLists * @return */ public static String buildCsvFileBodyMap(List dataLists) { //不管你传什么玩意，我都给你反射一手，搞成Map List<Map<String, Object>> mapList = new ArrayList<>(); for (Object o : dataLists) { mapList.add(toMap(o)); } //然后利用csv格式，对着map嘎嘎一顿拼接数据 StringBuilder lineBuilder = new StringBuilder(); for (Map<String, Object> rowData : mapList) { for (String key : rowData.keySet()) { Object value = rowData.get(key); if (Objects.nonNull(value)) { lineBuilder.append(value).append(MyCsvFileUtil.CSV_DELIMITER); } else { lineBuilder.append("--").append(MyCsvFileUtil.CSV_DELIMITER); } } lineBuilder.append(MyCsvFileUtil.CSV_TAIL); } return lineBuilder.toString(); } /** * 类转map * @param entity * @param <T> * @return */ public static<T> Map<String, Object> toMap(T entity){ Class<? extends Object> bean = entity.getClass(); Field[] fields = bean.getDeclaredFields(); Map<String, Object> map = new HashMap<>(fields.length); for(Field field:fields){ try { if(!"serialVersionUID".equals(field.getName())){ String methodName = "get"+field.getName().substring(0, 1).toUpperCase()+field.getName().substring(1); Method method = bean.getDeclaredMethod(methodName); Object fieldValue = method.invoke(entity); map.put(field.getName(),fieldValue); } } catch (Exception e) { log.warn("toMap() Exception={}",e.getMessage()); } } return map; } //新的反射解析拿字段属性注解值函数 public static <T> List<String> resolveExcelTableName(T entity) { List<String> tableNamesList = new ArrayList<>(); Class<? extends Object> bean = entity.getClass(); Field[] fields = bean.getDeclaredFields(); Map<String, Object> map = new HashMap<>(fields.length); for (Field field : fields) { try { if (!"serialVersionUID".equals(field.getName())) { String tableTitleName = field.getName(); JcExcelName myFieldAnn = field.getAnnotation(JcExcelName.class); String annName = myFieldAnn.name(); if (StringUtils.hasLength(annName)) { tableTitleName = annName; } tableNamesList.add(tableTitleName); } } catch (Exception e) { log.warn("toMap() Exception={}", e.getMessage()); } } return tableNamesList; } //然后根据解析出来的注解值列名拼接 表格标题名格式 public static String buildCsvFileTableNamesNew(List<String> dataList) { StringBuilder tableNames = new StringBuilder(); for (String name : dataList) { tableNames.append(name).append(MyCsvFileUtil.CSV_DELIMITER); } return tableNames.append(MyCsvFileUtil.CSV_TAIL).toString(); } }