基于Apache POI的Java读写excel的操作实现，网上的教程有很多，但是都不是很通用，尤其是在写操作的时候，你不知道写进来的数据格式是怎么样的，更无法去格式化。因此本文基于Apache POI，利用Java注解的方式，实现一个通用的Excel读写工具类。
一、Excel读操作
excel读操作相对比较简单，实现方式比较统一，就是读取excel的每一行，再读取每一列，将内容取出。具体实现如下。
/**
* 日期格式化
*/
private static final SimpleDateFormat sdf = new SimpleDateFormat("yyy-MM-dd HH:mm");
/**
* 整数格式化,取所有整数部分
*/
private static final DecimalFormat df = new DecimalFormat("#");
/**
* 读取Excel表格表头的内容
* @param inputStream
* @return String 表头内容的数组
*/
public static List<String> readExcelTitle(InputStream inputStream, String fileName) throws Exception {
List<String> titles = Lists.newArrayList();
Workbook workbook = getWorkbook(inputStream, fileName);
if (workbook == null) {
return titles;
}
Sheet sheet = workbook.getSheetAt(0);
//excel为空
if (sheet.getLastRowNum() == 0 && sheet.getPhysicalNumberOfRows() == 0) {
return titles;
}
//得到首行的row
Row row = sheet.getRow(0);
//标题总列数
int colNum = row.getPhysicalNumberOfCells();
for (int i = 0; i < colNum; i++) {
titles.add(getStringCellValue(row.getCell(i)));
}
return titles;
}
/**
* 读取excel文件内容
* @param inputStream 文件输入流, excel具体内容
* @param fileName 文件名,通过文件后缀名判断excel版本
* @return
* @throws Exception
*/
public static List<List<String>> readExcelContent(InputStream inputStream, String fileName) throws Exception {
List<List<String>> result = Lists.newArrayList();
Workbook workbook = getWorkbook(inputStream, fileName);
if (workbook == null) {
return result;
}
try {
Sheet sheet = workbook.getSheetAt(0);
Row row = sheet.getRow(0);
if (row == null) {
return result;
}
int colNum = row.getLastCellNum();
// 得到总行数
int rowNum = sheet.getLastRowNum();
// 正文内容应该从第二行开始,第一行为表头的标题
for (int i = 0; i <= rowNum; i++) {
row = sheet.getRow(i);
// 过滤空白行
if (isBlankRow(colNum, row)) {
continue;
}
List<String> rowContents = Lists.newArrayList();
for (int j = 0; j < colNum; j++) {
rowContents.add(getCellValue(row.getCell(j)));
}
result.add(rowContents);
}
} catch (Exception e) {
throw new Exception("excel解析失败！");
}
return result;
}
private static boolean isBlankRow(int colNum, Row row) {
for (int i = 0; i <= colNum; i++) {
// 只要有一列不为空, 该行就不为空行
if (StringUtils.isNotBlank(getCellValue(row.getCell(i)))) {
return false;
}
}
return true;
}
/**
* 获取workbook
*/
private static Workbook createWorkbook(String fileName) throws Exception {
Workbook workbook = null;
if (isExcel2003(fileName)) {
//2003 版本的excel
workbook = new HSSFWorkbook();
} else if (isExcel2007(fileName)) {
//2007 版本的excel
workbook = new XSSFWorkbook();
} else {
throw new Exception("file is not excel!");
}
return workbook;
}
/**
* 获取workbook
*/
private static Workbook getWorkbook(InputStream inputStream, String fileName) throws Exception {
Workbook workbook = null;
if (isExcel2003(fileName)) {
//2003 版本的excel
workbook = new HSSFWorkbook(inputStream);
} else if (isExcel2007(fileName)) {
//2007 版本的excel
workbook = new XSSFWorkbook(inputStream);
} else {
throw new Exception("Excel文件格式有误！");
}
return workbook;
}
/**
* 获取单元格数据内容为字符串类型的数据
* @param cell Excel单元格
* @return String 单元格数据内容
*/
private static String getStringCellValue(Cell cell) {
String cellValue = StringUtils.EMPTY;
if (cell != null) {
cellValue = cell.getStringCellValue().trim();
}
return cellValue;
}
/**
* 对表格中数值进行格式化
* @param cell Excel单元格
* @return
*/
public static String getCellValue(Cell cell) {
String value = StringUtils.EMPTY;
if (cell != null) {
switch (cell.getCellType()) {
case Cell.CELL_TYPE_STRING:
value = cell.getRichStringCellValue().getString().trim();
break;
case Cell.CELL_TYPE_NUMERIC:
if ("m/d/yy".equals(cell.getCellStyle().getDataFormatString())) {
value = sdf.format(cell.getDateCellValue());
} else if (HSSFDateUtil.isCellDateFormatted(cell)) {
Date date = cell.getDateCellValue();
value = sdf.format(date);
} else {
value = df.format(cell.getNumericCellValue());
}
break;
case Cell.CELL_TYPE_BOOLEAN:
value = String.valueOf(cell.getBooleanCellValue());
break;
case Cell.CELL_TYPE_BLANK:
break;
default:
break;
}
}
return value;
}
/**
* 是否是2003的excel，返回true是2003
*/
public static boolean isExcel2003(String filePath) {
return filePath.matches("^.+\\.(?i)(xls)$");
}
/**
* 是否是2007的excel，返回true是2007
*/
public static boolean isExcel2007(String filePath) {
return filePath.matches("^.+\\.(?i)(xlsx)$");
}
测试：
@Test
public void testRead() throws Exception {
// 对读取Excel表格标题测试
String fileName = "/Users/wanggenshen/Documents/testexcel.xlsx";
FileInputStream is = new FileInputStream(fileName);
List<List<String>> contents = ExcelUtil.readExcelContent(is, fileName);
System.out.println(contents.size());
}
二、Excel写
excel写操作需要确定写入的每一行的列数、每一列的类型，所以这里我用一个注解来映射写入的内容与excel每一列之间的关系。
@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
@Inherited
public @interface ExcelProperty {
/**
* 列顺序，越小越靠前
* @return 列顺序
*/
int rowIndex() default 99999;
/**
* 字段类型
*/
Class<?> fieldType();
}
然后就需要写一个写的方法，声明需要写入excel的表头、内容、每一列的类型。
public static File writeExcel(String filePath, List<String> titleList, List<List<String>> dataList, Class<?> clazz) throws Exception {
if(CollectionUtils.isEmpty(dataList)){
return new File(filePath);
}
Workbook workbook = null;
File file = new File(filePath);
FileOutputStream fos = null;
try {
fos = new FileOutputStream(file);
int colNum = dataList.get(0).size();
Map<Integer, Class<?>> colTypeMap = buildExcelColTypeMap(clazz);
if (MapUtils.isEmpty(colTypeMap) || colTypeMap.size() != colNum) {
throw new Exception("clazz type not math the excel cols");
}
fos = new FileOutputStream(file);
workbook = createWorkbook(filePath);
Sheet sheet = workbook.createSheet("sheet1");
// excel表头
Row row = sheet.createRow(0);
for (int index = 0; index < colNum; index++) {
Cell cell = row.createCell(index);
cell.setCellType(Cell.CELL_TYPE_STRING);
cell.setCellValue(titleList.get(index));
}
// 数据内容从第一行开始
for (int i = 0; i < dataList.size(); i++) {
row = sheet.createRow(i + 1);
List<String> rowContent = dataList.get(i);
for (int j = 0; j < colNum; j++) {
Class fieldType = colTypeMap.get(j + 1);
Cell cell = row.createCell(j);
writeCellValue(workbook, cell, rowContent.get(j), fieldType);
}
}
workbook.write(fos);
} finally {
if (fos != null) {
try {
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return file;
}
private static void writeCellValue(Workbook workbook, Cell cell, String value, Class fieldType) throws Exception {
try {
if (Integer.class == fieldType || java.lang.Long.class == fieldType) {
double d = NumberUtils.toDouble(String.valueOf(value));
cell.setCellValue(d);
cell.setCellType(Cell.CELL_TYPE_NUMERIC);
} else if (java.lang.Double.class == fieldType || java.lang.Float.class == fieldType) {
double d = NumberUtils.toDouble(String.valueOf(value));
cell.setCellValue(d);
cell.setCellType(Cell.CELL_TYPE_NUMERIC);
} else if (java.util.Date.class == fieldType) {
CellStyle cellStyle = workbook.createCellStyle();
short format = workbook.createDataFormat().getFormat("yyyy-mm-dd HH:mm");
cellStyle.setDataFormat(format);
Date date = DateUtils.parseDate(value, "yyyy-mm-dd HH:mm");
cell.setCellValue(date);
cell.setCellStyle(cellStyle);
cell.setCellType(Cell.CELL_TYPE_NUMERIC);
} else if (java.lang.String.class == fieldType) {
cell.setCellValue(value);
cell.setCellType(Cell.CELL_TYPE_STRING);
} else if (java.lang.Boolean.class == fieldType) {
cell.setCellValue(Boolean.valueOf(value));
cell.setCellType(Cell.CELL_TYPE_BOOLEAN);
} else {
cell.setCellValue("");
cell.setCellType(Cell.CELL_TYPE_BLANK);
}
} catch (Exception e) {
throw new Exception("invalid cell value format");
}
}
/**
* 构建excel每一列的类型
* @param clazz 标有ExcelProperty的注解
* @return
*/
private static Map<Integer, Class<?>> buildExcelColTypeMap(Class<?> clazz) throws Exception {
Map<Integer, Class<?>> excelColTypeMap = Maps.newHashMap();
Field[] fields = clazz.getDeclaredFields();
for (int i = 0; i < fields.length; i++) {
Field field = fields[i];
if (!field.isAnnotationPresent(ExcelProperty.class)) {
throw new Exception(String.format("Class field has no ExcelProperty Annotation", field));
}
ExcelProperty excelProperties = fields[i].getAnnotation(ExcelProperty.class);
excelColTypeMap.put(excelProperties.rowIndex(), excelProperties.fieldType());
}
return excelColTypeMap;
}
/**
* 获取workbook
*/
private static Workbook createWorkbook(String fileName) throws Exception {
Workbook workbook = null;
if (isExcel2003(fileName)) {
//2003 版本的excel
workbook = new HSSFWorkbook();
} else if (isExcel2007(fileName)) {
//2007 版本的excel
workbook = new XSSFWorkbook();
} else {
throw new Exception("file is not excel!");
}
return workbook;
}
/**
* 获取workbook
*/
private static Workbook getWorkbook(InputStream inputStream, String fileName) throws Exception {
Workbook workbook = null;
if (isExcel2003(fileName)) {
//2003 版本的excel
workbook = new HSSFWorkbook(inputStream);
} else if (isExcel2007(fileName)) {
//2007 版本的excel
workbook = new XSSFWorkbook(inputStream);
} else {
throw new Exception("Excel文件格式有误！");
}
return workbook;
}
/**
* 获取单元格数据内容为字符串类型的数据
* @param cell Excel单元格
* @return String 单元格数据内容
*/
private static String getStringCellValue(Cell cell) {
String cellValue = StringUtils.EMPTY;
if (cell != null) {
cellValue = cell.getStringCellValue().trim();
}
return cellValue;
}
/**
* 对表格中数值进行格式化
* @param cell Excel单元格
* @return
*/
public static String getCellValue(Cell cell) {
String value = StringUtils.EMPTY;
if (cell != null) {
switch (cell.getCellType()) {
case Cell.CELL_TYPE_STRING:
value = cell.getRichStringCellValue().getString().trim();
break;
case Cell.CELL_TYPE_NUMERIC:
if ("m/d/yy".equals(cell.getCellStyle().getDataFormatString())) {
value = sdf.format(cell.getDateCellValue());
} else if (HSSFDateUtil.isCellDateFormatted(cell)) {
Date date = cell.getDateCellValue();
value = sdf.format(date);
} else {
value = df.format(cell.getNumericCellValue());
}
break;
case Cell.CELL_TYPE_BOOLEAN:
value = String.valueOf(cell.getBooleanCellValue());
break;
case Cell.CELL_TYPE_BLANK:
break;
default:
break;
}
如何使用：
将要创建的excel格式如下：
首先需要利用注解，声明插入excel的内容与excel的关系：
public class ExcelConfigDTO {
@ExcelProperty(rowIndex = 1, fieldType = Long.class)
private long no;
@ExcelProperty(rowIndex = 2, fieldType = Integer.class)
private int score;
@ExcelProperty(rowIndex = 3, fieldType = String.class)
private String pass;
@ExcelProperty(rowIndex = 4, fieldType = String.class)
private String grade;
}
测试
@Test
public void testWrite() throws Exception {
// 对读取Excel表格标题测试
String fileName = "/Users/wanggenshen/Documents/testexcel.xlsx";
List<String> titleList = Lists.newArrayList("学号", "成绩", "是否及格", "年级");
List<List<String>> dataList = Lists.newArrayList();
List<String> data1 = Lists.newArrayList();
data1.add("12345");
data1.add("87");
data1.add("是");
data1.add("大二");
List<String> data2 = Lists.newArrayList();
data2.add("243455");
data2.add("56");
data2.add("否");
data2.add("大三");
dataList.add(data1);
dataList.add(data2);
ExcelUtil.writeExcel(fileName, titleList, dataList, ExcelUtil.ExcelConfigDTO.class);
System.out.println("写入成功");
}
就是这么简单。完整的代码见我的github：。