初级程序员一枚,看到公司大佬写的生成Excel文件,做下记录,同时也分享给大家参考
·······································实现原理是用workBook 然后还有OutputStream
首先是一个ExcelDataBean 这个实体类 用来 声明 Excel的最大行数,最大列数 以及用来保存 所传入的 标题列 内容列 并且对它们做出校验。
import java.util.ArrayList; import java.util.List; /** * 使用 Excel007Util 工具类创建 Excel 2007 文件所需要的数据类. * 包含多个包含标题信息的头列表 * 和多个内容行列表. * 超出 Excel 文件行列限制时会抛出异常, 不过没测试过这么大的数据. * * Created by gongsidalao on 17-5-10. */ public class ExcelDataBean { /** * 2007的是1048576行、16384列. */ public static final int MAX_ROW_SIZE = 1048576; public static final int MAX_COL_SIZE = 16384; private List<List<?>> headerList; private List<List<?>> rowList; public List<List<?>> getHeaderList() { return headerList; } public List<List<?>> getRowList() { return rowList; } private ExcelDataBean(List<List<?>> headerList, List<List<?>> rowList) { this.headerList = headerList; this.rowList = rowList; } public static class Builder { private List<List<?>> headerList; private List<List<?>> rowList; public Builder() { headerList = new ArrayList<>(); rowList = new ArrayList<>(); } public Builder addHeaderList(List<?> header) { if (header.size() > MAX_COL_SIZE) { throw new RuntimeException("数据列超出 Excel 允许的最大值!"); } if (headerList.size() + rowList.size() + 1 > MAX_ROW_SIZE) { throw new RuntimeException("数据行超出 Excel 允许的最大值!"); } this.headerList.add(header); return this; } public Builder addRowList(List<?> row) { if (row.size() > MAX_COL_SIZE) { throw new RuntimeException("数据列超出 Excel 允许的最大值!"); } if (headerList.size() + rowList.size() + 1 > MAX_ROW_SIZE) { throw new RuntimeException("数据行超出 Excel 允许的最大值!"); } this.rowList.add(row); return this; } public ExcelDataBean build() { return new ExcelDataBean(headerList, rowList); } } }
import org.apache.poi.ss.usermodel.*; import org.apache.poi.xssf.usermodel.XSSFWorkbook; import java.io.IOException; import java.io.OutputStream; import java.time.LocalDateTime; import java.time.ZoneId; import java.util.*; import java.util.stream.IntStream; /** * 使用 POI 创建一个简单的 Excel 文件 * Created by gongsidalao on 17-5-10. */ public class Excel2007Util { /** * * @param excelDataBean * @param outputStream * @throws IOException */ public static void createExcel(final ExcelDataBean excelDataBean, final OutputStream outputStream) throws IOException { //创建工作簿对象用于创建Sheet final Workbook workbook = new XSSFWorkbook();
//创建一个Sheet(纸)对象也就是一个EXCEL final Sheet sheet = workbook.createSheet(); //标题行数据List final List<List<?>> headerList = excelDataBean.getHeaderList(); //根据标题列的大小创建几个带有标题行的Sheet IntStream.range(0, headerList.size()) .forEach(i -> createRow(i, 0, headerList, sheet )); //行偏移量用于创建数据行的时候 做行偏移处理 如果只有一个标题行的话可以写死为1 final int rowOffset = headerList.size(); final List<List<?>> rowList = excelDataBean.getRowList(); IntStream.range(0, rowList.size()) .forEach(i -> createRow(i, rowOffset, rowList, sheet )); workbook.write(outputStream); } //创建行 private static void createRow(final int index, final int rowOffset, final List<List<?>> rowList, final Sheet sheet) { List<?> data = rowList.get(index); if (Objects.nonNull(data) && !data.isEmpty()) { final Row row = sheet.createRow(index + rowOffset); IntStream.range(0, data.size()) .forEach(j -> createCell(j, data, row)); } } //创建单元格 并且填充data private static void createCell(final int index, final List<?> data, final Row row) { final Object obj = data.get(index); final Cell cell = row.createCell(index); if (obj == null) { cell.setCellValue(""); } else if (Double.class.isInstance(obj)) { cell.setCellValue((double) obj); } else if (Date.class.isInstance(obj)) { Date date = (Date) obj; cell.setCellValue(LocalDateTime.ofInstant(date.toInstant(), ZoneId.systemDefault()).toString()); } else if (Calendar.class.isInstance(obj)) { cell.setCellValue((Calendar) obj); } else if (Boolean.class.isInstance(obj)) { cell.setCellValue((boolean) obj); } else { final CreationHelper createHelper = row.getSheet().getWorkbook().getCreationHelper(); cell.setCellValue(createHelper.createRichTextString(obj.toString())); } } }附上一个测试类以便测试
import org.junit.Test; import java.io.FileOutputStream; import java.io.IOException; import java.io.OutputStream; import java.util.*; /** * Created by gongsidalao on 17-5-11. */ public class Excel2007UtilTest { @Test public void TestUtil() { List<String> header = Arrays.asList("姓名", "年龄", "生日", "记录创建时间", "婚否", "备注"); List<Object> list1 = new ArrayList<>(); list1.add("AA"); list1.add(18); list1.add(Calendar.getInstance()); list1.add(new Date()); list1.add(true); list1.add(null); List<Object> list2 = new ArrayList<>(); list2.add("BB"); list2.add(18); list2.add(Calendar.getInstance()); list2.add(new Date()); list2.add(true); list2.add(null); System.out.println(list1.get(0)); String url = "L:/ceshi.xlsx"; try (OutputStream outputStream = new FileOutputStream(url)) { ExcelDataBean excelDataBean = new ExcelDataBean.Builder() .addHeaderList(header) // .addHeaderList(header) .addRowList(list1) .addRowList(list2) .build(); Excel2007Util.createExcel(excelDataBean, outputStream); } catch (IOException e) { e.printStackTrace(); } } }有什么不足的还望大家指出来,高手轻喷,做个日常记录以便学习.