POI：Excel表解析与导出通用工具类

一，概述

好几个项目都需要与Excel打交道，每次都要特地去解析、导出，费时费力！所以参考了两位作者的文章，整理了一下POI导入导出的通用工具类。虽说是通用工具类，也只能对那些比较规则的Excel表进行操作，对于那些不规则的Excel表，还是要撸起袖子加油干！（下面这张图是POI的单元格数据类型）

二，实现

1，主要依赖

POI的一些依赖以及阿里的fastjson

 <!-- POI Excel表 --><dependency><groupId>org.apache.poi</groupId><artifactId>poi</artifactId><version>3.17</version></dependency><dependency><groupId>org.apache.poi</groupId><artifactId>poi-ooxml</artifactId><version>3.17</version></dependency><dependency><groupId>org.apache.poi</groupId><artifactId>poi-excelant</artifactId><version>3.17</version></dependency><dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.51</version></dependency>

2，解析Excel表工具类

1)解析Excel表工具类，我参考了一位作者的博文（非常感谢！！！），并做了一些优化——POI读取excel文件通用代码（增强版--支持返回javaBean集合）---2003,2007

2)完整代码

package com.statement.utils.excel;import com.alibaba.fastjson.JSONObject;
import com.statement.pojo.YlswBranch;
import org.apache.poi.hssf.usermodel.HSSFDateUtil;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.util.NumberToTextConverter;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Date;
import java.util.List;/*** Execel(2003->xls,2007以上->xlsx)解析工具类*/
public class ParseExcelUtil {//2003版本 最大支持65536 行private static final String EXCEL_XLS = "xls";//2007 版本以上 最大支持1048576行private static final String EXCEL_XLSX = "xlsx";private static List<String> columns;//要解析excel中的列名private static int sheetNum = 0;//要解析的sheet下标public static List<String> getColumns() {return ParseExcelUtil.columns;}public static void setColumns(List<String> columns) {ParseExcelUtil.columns = columns;}public static int getSheetNum() {return sheetNum;}public static void setSheetNum(int sheetNum) {ParseExcelUtil.sheetNum = sheetNum;}/*** 判断Excel的版本,获得对应的Workbook** @param file* @return* @throws Exception*/public static Workbook getWorkbook(File file) {Workbook wb = null;try {checkExcelValid(file);InputStream in = new FileInputStream(file);if (file.getName().endsWith(EXCEL_XLS)) {//Excel2003及以下wb = new HSSFWorkbook(in);} else if (file.getName().endsWith(EXCEL_XLSX)) {//Excel2007及以上wb = new XSSFWorkbook(in);}} catch (Exception e) {e.printStackTrace();wb = null;}return wb;}/*** 直接传入输入流和文件名（xxx.xls或xxx.xlsx）获取对应的Workbook** @param ins* @param fileName* @return*/public static Workbook getWorkbook(InputStream ins, String fileName) {Workbook wb = null;try {if (!fileName.endsWith(EXCEL_XLS) && !fileName.endsWith(EXCEL_XLSX)) {throw new Exception("不是标准的Excel文件");}if (fileName.endsWith(EXCEL_XLS)) {//Excel2003及以下wb = new HSSFWorkbook(ins);} else if (fileName.endsWith(EXCEL_XLSX)) {//Excel2007及以上wb = new XSSFWorkbook(ins);}} catch (Exception e) {e.printStackTrace();wb = null;}return wb;}/*** 判断Excel文件是否有效,无效时抛出异常** @param file* @throws Exception*/public static void checkExcelValid(File file) throws Exception {//System.out.println("filename:" + file.getName());if (!file.exists()) {//文件不存在throw new Exception("文件不存在");} else if (!(file.isFile() && (file.getName().endsWith(EXCEL_XLS) || file.getName().endsWith(EXCEL_XLSX)))) {throw new Exception("不是标准的Excel文件");}}/*** 获取Excel文件中，从startIndex到(总行数-endIndex)之间的数据，返回json数组** @param file* @param startIndex* @return*/public static String readExcel(File file, int startIndex, int endIndex) {StringBuilder retJson = new StringBuilder();Workbook workbook = getWorkbook(file);Sheet sheet = workbook.getSheetAt(sheetNum);int lastRowNum = sheet.getLastRowNum();//最后一行System.out.println("lastRowNum:" + lastRowNum);retJson.append("[");//for (int i = 0; i < lastRowNum; i++) {for (int i = startIndex; i < lastRowNum - endIndex; i++) {Row row = sheet.getRow(i);//获得行String rowJson = readExcelRow(row);retJson.append(rowJson);if (i < lastRowNum - 1)retJson.append(",");}retJson.append("]");try {//关闭资源workbook.close();} catch (IOException e) {e.printStackTrace();} finally {return retJson.toString();}}/*** 网页上传文件时，通过流的方式更为便捷，从startIndex到(总行数-endIndex)之间的数据，返回json数组** @param ins* @param fileName* @param startIndex* @param endIndex* @return*/public static String readExcel(InputStream ins, String fileName, int startIndex, int endIndex) {StringBuilder retJson = new StringBuilder();Workbook workbook = getWorkbook(ins, fileName);Sheet sheet = workbook.getSheetAt(sheetNum);int lastRowNum = sheet.getLastRowNum();//最后一行System.out.println("lastRowNum:" + lastRowNum);retJson.append("[");//for (int i = 0; i < lastRowNum; i++) {for (int i = startIndex; i < lastRowNum - endIndex; i++) {Row row = sheet.getRow(i);//获得行String rowJson = readExcelRow(row);retJson.append(rowJson);if (i < lastRowNum - 1)retJson.append(",");}retJson.append("]");try {//关闭资源workbook.close();} catch (IOException e) {e.printStackTrace();} finally {return retJson.toString();}}/*** 将json转换为集合，使用阿里的fastjson框架非常便捷** @param json* @param clazz* @param <E>* @return*/public static <E> Collection<E> readExcel(String json, Class<E> clazz) {return JSONObject.parseArray(json, clazz);}/*** 读取每行Row的数据，每行数据对应一个javabean** @param row* @return 返回一个json对象*/private static String readExcelRow(Row row) {StringBuilder rowJson = new StringBuilder();int lastCellNum = ParseExcelUtil.columns.size();//最后一个单元格rowJson.append("{");for (int i = 0; i < lastCellNum; i++) {Cell cell = row.getCell(i);String cellVal = readCellValue(cell);rowJson.append(toJsonItem(columns.get(i), cellVal));if (i < lastCellNum - 1)rowJson.append(",");}rowJson.append("}");return rowJson.toString();}/*** 读取每个单元格Cell的value,对NUMERIC类型的Cell需要做特别处理** @param cell* @return 返回Cell的value*/@SuppressWarnings("static-access")private static String readCellValue(Cell cell) {if (cell == null) {return null;}CellType type = cell.getCellTypeEnum();String cellValue;switch (type) {case BLANK:cellValue = "";break;case _NONE:cellValue = "";break;case ERROR:cellValue = "";break;case BOOLEAN:cellValue = String.valueOf(cell.getBooleanCellValue());break;case NUMERIC://cellValue = String.valueOf(cell.getNumericCellValue());//当Cell为日期类型(如2018-11-19)时，需要做特殊处理，否则解析出来的将会是一个距离1900年1月1日的天数(此时为43423)if (HSSFDateUtil.isCellDateFormatted(cell)) {//日期类型Date date = cell.getDateCellValue();DateFormat formater = new SimpleDateFormat("yyyy-MM-dd");cellValue = formater.format(date);} else {//货币类型 等等//如果Cell是科学计数法类型的数据或者货币类型时，获取不到想要的字符串，此时通过NumberToTextConverter工具类// 的toText(...)方法可以解决该问题，获取字符串cellValue = NumberToTextConverter.toText(cell.getNumericCellValue());}break;case STRING:cellValue = cell.getStringCellValue();break;case FORMULA:cellValue = cell.getCellFormula();break;default:cellValue = "";break;}return cellValue;}/*** 转换为json对** @return*/private static String toJsonItem(String name, String val) {return "\"" + name + "\":\"" + val + "\"";}public static void main(String[] args) {File file = new File("C:\\Users\\Administrator\\IdeaProjects\\statement\\src\\main\\resources\\10050003400000_20181120_1_test.xlsx");List<String> list = new ArrayList<>();list.add("mrchNo");list.add("transDate");list.add("transTime");list.add("terminalNo");list.add("transType");list.add("cardNo");list.add("transAmount");list.add("clearAmount");list.add("poundage");list.add("flowNo");list.add("sysTracking");list.add("cardType");list.add("transReferNo");list.add("bank");//  list.add("orderNo");ParseExcelUtil.setColumns(list);String json = ParseExcelUtil.readExcel(file, 3, 1);Collection<YlswBranch> ylswBranches = ParseExcelUtil.readExcel(json, YlswBranch.class);System.out.println("*************************");System.out.println("ylswBranches1.size():" + ylswBranches.size());for (YlswBranch yl : ylswBranches) {System.out.println(yl);}}}

主要做法就是通过readExcelRow(Row row)将Excel表中每行的数据做成json对象，在readExcel(File file, int startIndex, int endIndex)或readExcel(InputStream ins,String fileName, int startIndex, int endIndex)方法中将全部的json对象组成一个json数组。有了一个json数组，通过阿里的fastjson框架，可轻松转换成一个集合，对应为readExcel(String json, Class<E> clazz)方法。

3)测试（测试代码在工具类的main方法中）

a)解析10050003400000_20181120_1_test.xlsx

b)对应实体属性如下

    private String mrchNo;private String transDate;private String transTime;private String terminalNo;private String transType;private String cardNo;private String transAmount;private String clearAmount;private String poundage;private String flowNo;private String sysTracking;private String cardType;private String transReferNo;private String bank;private String orderNo;

c)获取文件，ParseExcelUtil.setColumns(list)设置Excel文件中每一列对应的名称，执行解析方法ParseExcelUtil.readExcel(file, 3, 1)获得json数组，最后通过ParseExcelUtil.readExcel(json, YlswBranch.class)得到对应的集合。

        ParseExcelUtil.setColumns(list);//从第4行开始解析，直到最后一行前一行String json = ParseExcelUtil.readExcel(file, 3, 1);Collection<YlswBranch> ylswBranches = ParseExcelUtil.readExcel(json, YlswBranch.class);System.out.println("*************************");System.out.println("ylswBranches1.size():" + ylswBranches.size());for (YlswBranch yl : ylswBranches) {System.out.println(yl);}

集合打印如下：

3 ，导出Excel工具类

1)导出工具类参考了一位作者的博文，精简了一些代码，原文为Java之——导出Excel通用工具类

2)工具类有两个：ExportExcelUtil、ExportExcelWrapper，后者继承前者，后置主要提供网页点击按钮生成Excel文件的快捷操作。

3)ExportExcelUtil代码：

package com.statement.utils.excel;import java.io.IOException;
import java.io.OutputStream;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.text.SimpleDateFormat;
import java.util.Collection;
import java.util.Date;
import java.util.Iterator;
import java.util.regex.Matcher;
import java.util.regex.Pattern;import org.apache.commons.lang3.StringUtils;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;public class ExportExcelUtil<T> {// 2007 版本以上 最大支持1048576行public final static String EXCEl_FILE_2007 = "2007";// 2003 版本 最大支持65536 行public final static String EXCEL_FILE_2003 = "2003";/*** 通过版本类判断是** @param sheetName 表格标题名* @param headers   表格头部标题集合* @param dataset   数据集合* @param out       输出流* @param version   指定生成Excel文件的版本*/public void exportExcel(String sheetName, String[] headers, Collection<T> dataset, OutputStream out, String version) {Workbook workbook = null;if (StringUtils.isBlank(version) || EXCEL_FILE_2003.equals(version.trim())) {workbook = new HSSFWorkbook();} else {workbook = new XSSFWorkbook();}exportExcel(workbook, sheetName, headers, dataset, out, "yyyy-MM-dd HH:mm:ss");}/*** 通用Excel导出方法,利用反射机制遍历对象的所有字段，将数据写入Excel文件中 <br>* 此版本生成2007以上版本的文件 (文件后缀：xlsx)** @param sheetName 表格标题名* @param headers   表格头部标题集合* @param dataset   需要显示的数据集合,集合中一定要放置符合JavaBean风格的类的对象。此方法支持的*                  JavaBean属性的数据类型有基本数据类型及String,Date* @param out       与输出设备关联的流对象，可以将EXCEL文档导出到本地文件或者网络中* @param pattern   如果有时间数据，设定输出格式。默认为"yyyy-MM-dd hh:mm:ss"*/public void exportExcel(Workbook workbook, String sheetName, String[] headers, Collection<T> dataset, OutputStream out, String pattern) {// 生成一个表格Sheet sheet = workbook.createSheet(sheetName);// 设置表格默认列宽度为15个字节//设置宽度//sheet.setDefaultColumnWidth(20);sheet.setDefaultColumnWidth(18);//sheet.trackAllColumnsForAutoSizing();
//        sheet.autoSizeColumn(0);// 生成一个样式CellStyle style = workbook.createCellStyle();style.setAlignment(HorizontalAlignment.CENTER);//内容居中// 生成一个字体Font font = workbook.createFont();font.setFontName("宋体");font.setBold(true);//加粗font.setFontHeightInPoints((short) 11);// 把字体应用到当前的样式style.setFont(font);// 生成并设置另一个样式CellStyle style2 = workbook.createCellStyle();style2.setAlignment(HorizontalAlignment.CENTER);// 生成另一个字体Font font2 = workbook.createFont();// font2.setBold(true);//加粗// 把字体应用到当前的样式style2.setFont(font2);// 产生表格标题行Row row = sheet.createRow(0);Cell cellHeader;for (int i = 0; i < headers.length; i++) {cellHeader = row.createCell(i);cellHeader.setCellStyle(style);cellHeader.setCellValue(headers[i]);}// 遍历集合数据，产生数据行Iterator<T> it = dataset.iterator();int index = 0;T t;Field[] fields;Field field;//HSSFRichTextString richString;Pattern p = Pattern.compile("^//d+(//.//d+)?$");Matcher matcher;String fieldName;String getMethodName;Cell cell;Class tCls;Method getMethod;Object value;String textValue;SimpleDateFormat sdf = new SimpleDateFormat(pattern);while (it.hasNext()) {index++;row = sheet.createRow(index);t = (T) it.next();// 利用反射，根据JavaBean属性的先后顺序，动态调用getXxx()方法得到属性值fields = t.getClass().getDeclaredFields();for (int i = 0; i < fields.length; i++) {cell = row.createCell(i);cell.setCellStyle(style2);field = fields[i];fieldName = field.getName();getMethodName = "get" + fieldName.substring(0, 1).toUpperCase()+ fieldName.substring(1);try {tCls = t.getClass();getMethod = tCls.getMethod(getMethodName, new Class[]{});value = getMethod.invoke(t, new Object[]{});// 判断值的类型后进行强制类型转换textValue = null;if (value instanceof Integer) {cell.setCellValue((Integer) value);} else if (value instanceof Float) {textValue = String.valueOf((Float) value);cell.setCellValue(textValue);} else if (value instanceof Double) {textValue = String.valueOf((Double) value);cell.setCellValue(textValue);} else if (value instanceof Long) {cell.setCellValue((Long) value);}if (value instanceof Boolean) {textValue = "是";if (!(Boolean) value) {textValue = "否";}} else if (value instanceof Date) {textValue = sdf.format((Date) value);} else {// 其它数据类型都当作字符串简单处理if (value != null) {textValue = value.toString();}}if (textValue != null) {matcher = p.matcher(textValue);if (matcher.matches()) {// 是数字当作double处理cell.setCellValue(Double.parseDouble(textValue));} else {// richString = new HSSFRichTextString(textValue);cell.setCellValue(textValue);}}} catch (SecurityException e) {e.printStackTrace();} catch (NoSuchMethodException e) {e.printStackTrace();} catch (IllegalArgumentException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();} catch (InvocationTargetException e) {e.printStackTrace();}}}try {workbook.write(out);} catch (IOException e) {e.printStackTrace();} finally {try {//关闭资源workbook.close();} catch (IOException e) {e.printStackTrace();}}}}

4)ExportExcelWrapper代码：

package com.statement.utils.excel;import java.io.OutputStream;
import java.net.URLEncoder;
import java.util.Collection;import javax.servlet.http.HttpServletResponse;import org.apache.commons.lang3.StringUtils;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;/*** 供网页端点击按钮，自动生成并下载Excel表** @param <T>*/
public class ExportExcelWrapper<T> extends ExportExcelUtil {/*** 导出带有头部标题行的Excel* 时间格式默认：yyyy-MM-dd hh:mm:ss** @param fileName 生成的Excel文件名字(不要加后缀)* @param title    表格标题* @param headers  头部标题集合* @param dataset  数据集合* @param response* @param version  2003 或者 2007，不传时默认生成2003版本*/public void exportExcel(String fileName, String title, String[] headers, Collection<T> dataset, HttpServletResponse response, String version) {try {response.setContentType("application/vnd.ms-excel");String suffix = null;if (StringUtils.isBlank(version) || EXCEL_FILE_2003.equals(version.trim())) {suffix = ".xls";} else {suffix = ".xlsx";}response.addHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8") + suffix);Workbook workbook = null;if (StringUtils.isBlank(version) || EXCEL_FILE_2003.equals(version.trim())) {workbook = new HSSFWorkbook();} else {workbook = new XSSFWorkbook();}exportExcel(workbook, title, headers, dataset, response.getOutputStream(), "yyyy-MM-dd HH:mm:ss");} catch (Exception e) {e.printStackTrace();}}}

思路：

a)在ExportExcelUtil工具类中，通过方法中传入的version来生成对应的Workbook，然后再调用生成Excel文件的核心方法生成目标文件，核心逻辑来自参考文章（再次感谢那位大佬！）。
exportExcel(Workbook workbook, String sheetName, String[] headers, Collection<T> dataset, OutputStream out, String pattern)
b)ExportExcelWrapper<T>继承ExportExcelUtil，重载了exportExcel方法，加入了一个response，主要实现逻辑也是调用父类的方法。

exportExcel(String fileName, String title, String[] headers, Collection<T> dataset, HttpServletResponse response, String version)

5)测试

a)解析和生成一起测试

 public static void main(String[] args) {File file = new File("C:\\Users\\Administrator\\IdeaProjects\\statement\\src\\main\\resources\\10050003400000_20181120_1_test.xlsx");List<String> list = new ArrayList<>();list.add("mrchNo");list.add("transDate");list.add("transTime");list.add("terminalNo");list.add("transType");list.add("cardNo");list.add("transAmount");list.add("clearAmount");list.add("poundage");list.add("flowNo");list.add("sysTracking");list.add("cardType");list.add("transReferNo");list.add("bank");//  list.add("orderNo");ParseExcelUtil.setColumns(list);String json = ParseExcelUtil.readExcel(file, 3, 1);Collection<YlswBranch> ylswBranches = ParseExcelUtil.readExcel(json, YlswBranch.class);System.out.println("*****************11111111111111111111111**************************");System.out.println("ylswBranches1.size():" + ylswBranches.size());for (YlswBranch yl : ylswBranches) {System.out.println(yl);}System.out.println("*****************11111111111111111111111**************************");ExportExcelUtil<YlswBranch> util = new ExportExcelUtil<YlswBranch>();// 准备数据String[] columnNames = {"mrchNo", "transDate", "transTime", "terminalNo","transType", "cardNo", "transAmount", "clearAmount","poundage", "flowNo", "sysTracking", "cardType","transReferNo", "bank", "orderNo"};try {// util.exportExcel("用户导出", columnNames, ylswBranches, new FileOutputStream("E:/testExcel.xlsx"), ExportExcelUtil.EXCEl_FILE_2007);util.exportExcel("用户导出", columnNames, ylswBranches, new FileOutputStream("E:/testExcel33.xls"), ExportExcelUtil.EXCEL_FILE_2003);} catch (FileNotFoundException e) {e.printStackTrace();}System.out.println("程序执行成功！！！！！！！！！！");}

b)测试ExportExcelWrapper

@Controller
@RequestMapping("/test")
public class TestController {@RequestMapping("/excel")public void getExcel(HttpServletRequest request, HttpServletResponse response) throws Exception {ExportExcelWrapper<AccountBill> util = new ExportExcelWrapper<AccountBill>();// 准备数据List<AccountBill> list = new ArrayList<>();for (int i = 0; i < 10; i++) {//没有给实体的所有属性赋值AccountBill accountBill = new AccountBill();accountBill.setClearDate("20180923");accountBill.setTransAmount("23424234234");accountBill.setTransDate("2018083209");accountBill.setTransType("支付宝");accountBill.setTransAmount("10000000");accountBill.setOriginalPayReferNo("dfsdfsdffasdfas");accountBill.setCardNo("234234*************324234");list.add(accountBill);}String[] columnNames = {"清算日期", "交易日期", "交易时间", "商户号","终端号", "交易类型", "卡号", "总交易金额","总清算金额", "总手续费", "参考号", "流水号","卡类型", "发卡行", "订单号", "原缴费参考号","备注"};String fileName = "testAccountBill";//网页导出Excel表util.exportExcel(fileName, "用户导出", columnNames, list, response, ExportExcelUtil.EXCEl_FILE_2007);//  util.exportExcel("用户导出", columnNames, list, new FileOutputStream("E:/testAccountBill111.xlsx"), ExportExcelUtil.EXCEl_FILE_2007);System.out.println("程序执行了！！！！！！！！！！！");}
}

在浏览器上输入：http://127.0.0.1:6225/test/get/excel ，浏览器就可直接下载文件了。部分效果图如下：

三，总结

1，在开发中，经常遇到解析Excel表获取数据和导出数据到Excel表中的需求，还是要准备工具类，提高开发效率！

2，本文中的工具类也只能对那些比较规则的导入导出起作用，对于那些比较复杂的Excel表，无论是解析还是导出，均需要作出特别处理，还是偷不了懒！

3，参考了两位作者的文章，再次感谢！