Excel导入导出简单示例，希望可以帮助到你。如果你的业务更复杂一点的话，可以在此基础上稍作修改。实现的方式有很多，如果有时间可以自己再研究其他实现方式。
谈谈我的看法：主要理解工作薄、工作表、行、列（单元格）之间的关系；
项目结构截图：
pom.xml引入的依赖
<dependencies>
<!-- https://mvnrepository.com/artifact/org.apache.poi/poi -->
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi</artifactId>
<version>4.1.2</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.poi/poi-ooxml -->
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>4.1.2</version>
</dependency>
<!-- https://mvnrepository.com/artifact/joda-time/joda-time -->
<dependency>
<groupId>joda-time</groupId>
<artifactId>joda-time</artifactId>
<version>2.10.5</version>
</dependency>
</dependencies>
工具类：ExcelSuffix.java
public class ExcelSuffix {
/**
* excel 03版本后缀
*/
public static final String EXCEL03PREFIX = ".xls";
/**
* excel 07版本后缀
*/
public static final String EXCEL07PREFIX = ".xlsx";
/**
* 文件路径
*/
public static final String PATH = "C:\\Desktop\\";
}Excel读操作：
/**
* Excel 读数据
*/
public class ExcelRead {
/**
* 03版本的读取文件指定单元格内容
*/
@Test
public void excelRead03V() throws Exception {
FileInputStream fStream = new FileInputStream(ExcelSuffix.PATH + "excel03" + ExcelSuffix.EXCEL03PREFIX);
Workbook workbook = new HSSFWorkbook(fStream);
Sheet sheet = workbook.getSheetAt(0);
Row row = sheet.getRow(0);
Cell cell = row.getCell(0);
String cellValue = cell.getStringCellValue();
System.out.println("获取第一个单元格的内容 : " + cellValue);
fStream.close();
}
/**
* 07版本的读取文件指定单元格内容
*/
@Test
public void excelRead07V() throws Exception {
FileInputStream fStream = new FileInputStream(ExcelSuffix.PATH + "excel07" + ExcelSuffix.EXCEL07PREFIX);
Workbook workbook = new XSSFWorkbook(fStream);
Sheet sheet = workbook.getSheetAt(0);
Row row = sheet.getRow(0);
Cell cell = row.getCell(0);
String cellValue = cell.getStringCellValue();
System.out.println("获取第一个单元格的内容 : " + cellValue);
fStream.close();
}
/**
* 读取文件数据并判断类型
*/
@Test
public void excelRead() throws Exception {
// 加载文件数据
FileInputStream inputStream = new FileInputStream(ExcelSuffix.PATH + "03明细" + ExcelSuffix.EXCEL03PREFIX);
Workbook workbook = new HSSFWorkbook(inputStream);// 创建工作薄
Sheet sheet = workbook.getSheetAt(0);// 获取工作表
// 获取标题
Row rowTitle = sheet.getRow(0);
int cellCount = 0;
if (rowTitle != null) {
cellCount = rowTitle.getPhysicalNumberOfCells();//获取有多少列
for (int cellNumi = 0; cellNumi < cellCount; cellNumi++) {
Cell cell = rowTitle.getCell(cellNumi);//获取列
if (cell != null) {
String cellValue = cell.getStringCellValue();//获取单元格的值
System.out.print(cellValue + " | ");
}
}
System.out.println();
}
int rowCount = sheet.getPhysicalNumberOfRows();// 获取行数
for (int rowNum = 1; rowNum < rowCount; rowNum++) {
Row row = sheet.getRow(rowNum);
if (row != null) {
for (int i = 0; i < cellCount; i++) {
Cell cell = row.getCell(i);
if (cell != null) {
CellType cellType = cell.getCellType();
String cellValue = "";
switch (cellType) {
case STRING:// 字符串
cellValue = cell.getStringCellValue();
System.out.print(cellValue + " | ");
break;
case NUMERIC:// 数字(日期、普通数字)
if (DateUtil.isCellDateFormatted(cell)) {// true说明是日期
Date date = cell.getDateCellValue();
cellValue = new DateTime(date).toString("yyyy-MM-dd");
} else {//数字的话转字符串
cell.setCellType(CellType.STRING);
cellValue = cell.getStringCellValue();
}
System.out.print(cellValue + " | ");
break;
case BOOLEAN://布尔类型
cellValue = String.valueOf(cell.getBooleanCellValue());
System.out.println(cellValue);
break;
case BLANK://空
break;
default:
break;
}
}
}
}
System.out.println();
}
}
}
Excel写操作：
/**
* excel 写操作的基本使用
*/
public class BaseExcelWrite {
/**
* 03版本的excel的基本写操作示例
*/
@Test
public void excel03V() throws Exception{
Workbook workbook = new HSSFWorkbook();//创建工作薄
Sheet sheet = workbook.createSheet("sheet03");//创建工作表
Row row = sheet.createRow(0);//创建行
Cell cell = row.createCell(0);//创建列
cell.setCellValue("03版本cell1");//填写内容
Cell cell2 = row.createCell(1);
cell2.setCellValue("03版本cell2");
//创建流
FileOutputStream outputStream = new FileOutputStream(ExcelSuffix.PATH + "excel03" + ExcelSuffix.EXCEL03PREFIX);
workbook.write(outputStream);//写操作
//关闭流
outputStream.close();
}
/**
* 07版本的excel的基本写操作示例
*/
@Test
public void excel07V() throws Exception{
Workbook workbook = new XSSFWorkbook();//创建工作薄
Sheet sheet = workbook.createSheet("sheet07");//创建工作表
Row row = sheet.createRow(0);//创建行
Cell cell = row.createCell(0);//创建列
cell.setCellValue("07版本cell1");//填写内容
Cell cell2 = row.createCell(1);
cell2.setCellValue("07版本cell2");
//创建流
FileOutputStream outputStream = new FileOutputStream(ExcelSuffix.PATH + "excel07" + ExcelSuffix.EXCEL07PREFIX);
workbook.write(outputStream);//写操作
//关闭流
outputStream.close();
}
}
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/**
* excel 大数据量的操作
*/
public class BigExcelWrite {
/**
* HSSF<br/>
* 缺点:最多只能处理65535行数据,否则会报如下异常:
* java.lang.IllegalArgumentException: Invalid row number (65536) outside allowable range (0..65535)
* 优点:过程中写入缓存,不操作磁盘,最后一次性写入到文件中,速度相对较快
*/
@Test
public void excelWrite03V() throws Exception{
long beginTime = System.currentTimeMillis();//开始时间
Workbook workbook = new HSSFWorkbook();//创建工作薄
Sheet sheet = workbook.createSheet("03excel_bigdata");//创建工作表
for (int rowNum = 0; rowNum < 65536; rowNum++) {
Row row = sheet.createRow(rowNum);//创建行
for (int cellNumj = 0; cellNumj < 10; cellNumj++) {
Cell cell = row.createCell(cellNumj);//创建列
cell.setCellValue("data" + cellNumj);//填写内容
}
}
//创建流
FileOutputStream outputStream = new FileOutputStream(ExcelSuffix.PATH + "03bigdata" + ExcelSuffix.EXCEL03PREFIX);
workbook.write(outputStream);//写操作
//关闭流
outputStream.close();
long endTime = System.currentTimeMillis();
System.out.println((double)(endTime - beginTime)/1000);//3.268
}
/**
* XSSF<br/>
* 缺点:写数据时,速度非常慢,非常耗内存,也会发生内存溢出,如100w条
* 优点:可以写较大的数据量,如20w条
*/
@Test
public void excelWrite07V() throws Exception{
long beginTime = System.currentTimeMillis();//开始时间
Workbook workbook = new XSSFWorkbook();//创建工作薄
Sheet sheet = workbook.createSheet("07excel_bigdata");
for (int rowNum = 0; rowNum < 65536; rowNum++) {
Row row = sheet.createRow(rowNum);//创建行
for (int cellNumj = 0; cellNumj < 10; cellNumj++) {
Cell cell = row.createCell(cellNumj);//创建列
cell.setCellValue("data" + cellNumj);//填写内容
}
}
//创建流
FileOutputStream outputStream = new FileOutputStream(ExcelSuffix.PATH + "07bigdata" + ExcelSuffix.EXCEL07PREFIX);
workbook.write(outputStream);//写操作
//关闭流
outputStream.close();
long endTime = System.currentTimeMillis();//接收时间
System.out.println((double)(endTime - beginTime)/1000);//22.104
}
/**
* SXSSF<br/>
* 优点:可以写非常大的数据量,写数据速度快,占用更少的内存
* 注意:过程总会产生临时文件,需要清理临时文件;默认由100条记录被保存在内存中,如果超过这个数量,则最
* 前面的数据被写入临时文件,如果想要自定义内存中的数据的数量,可以使用new SXSSFWorkbook(数量)
* 有些事情不是绝对的,也有可能占用大量内存
*/
@Test
public void excelWriteBigData() throws Exception {
long beginTime = System.currentTimeMillis();//开始时间
Workbook workbook = new SXSSFWorkbook();//创建工作薄
Sheet sheet = workbook.createSheet("bigData");//创建工作表
for(int rowNum = 0;rowNum < 1000000; rowNum ++) {
Row row = sheet.createRow(rowNum);
for (int cellNum = 0; cellNum < 10; cellNum++) {
Cell cell = row.createCell(cellNum);
cell.setCellValue("bigData" + cellNum);
}
}
//创建流
FileOutputStream fStream = new FileOutputStream(ExcelSuffix.PATH + "bigData" + ExcelSuffix.EXCEL07PREFIX);
//写操作
workbook.write(fStream);
//关闭流
fStream.close();
//清除临时文件
((SXSSFWorkbook) workbook).dispose();
long endTime = System.currentTimeMillis();
System.out.println((double)(endTime-beginTime)/1000);//30.02
}
}
Excel基本读取：
/**
* Excel基本读取
*/
public class ReadExcel {
public static void main(String[] args) throws Exception {
FileInputStream fStream = new FileInputStream(ExcelSuffix.PATH + "03明细" + ExcelSuffix.EXCEL03PREFIX);
Object object = excelReader(fStream,0);
}
/**
* Excel 读取方法
* @param fStream 文件流
* @param sheetIndex 工作表下标索引
*/
public static Object excelReader(FileInputStream fStream, int sheetIndex) throws IOException {
Workbook wk = new HSSFWorkbook(fStream);// 创建工作薄并将文件流加载到内存中
int sheets = wk.getNumberOfSheets();// 获取所有工作表的个数
int sheetAt = 0;//工作表下标索引
if(sheetIndex <= sheets) sheetAt = sheetIndex;//从第几个工作表开始
for (; sheetAt < sheets; sheetAt++) {// 循环工作表
Sheet sheet = wk.getSheetAt(sheetAt);// 获取具体的工作表
int rows = sheet.getPhysicalNumberOfRows();// 获取工作表的行数
for (int i = 0; i < rows; i++) {// 循环行
Row row = sheet.getRow(i);// 获取具体的行
if (row != null) {// 判断行对象是否为空
int cells = row.getPhysicalNumberOfCells();// 获取行中的列(单元格)个数
for (int j = 0; j < cells; j++) {// 循环单元格,准备获取内容了
Cell cell = row.getCell(j);// 获取具体的单元格
if (cell != null) {// 判断单元格是否为空
//CellType cellType = cell.getCellType();// 获取单元格内容的类型
String cellValue = handleValueByCellType(cell);
System.out.println(cellValue);
//TODO 在这里做"坏事"
}
}
}
}
}
return null;//TODO 这里需要返回结果
}
/**
* 根据单元格类型处理单元格内容
* @param cell 单元格对象
* @deprecated 如果case中类型没有,可自行添加上
*/
public static String handleValueByCellType(Cell cell) {
String cellValue = "";
CellType cellType = cell.getCellType();
switch (cellType) {
case STRING:
cellValue = cell.getStringCellValue();
break;
case NUMERIC:// 数字(日期、普通数字)
if (DateUtil.isCellDateFormatted(cell)) {// true说明是日期
Date date = cell.getDateCellValue();
cellValue = new DateTime(date).toString("yyyy-MM-dd");
} else {// 数字的话转字符串
cell.setCellType(CellType.STRING);
cellValue = cell.getStringCellValue();
}
break;
case BOOLEAN://布尔类型
cellValue = String.valueOf(cell.getBooleanCellValue());
break;
case BLANK://空
break;
default:
break;
}
return cellValue;
}
}
Excel读取到封装对象：
public class ExcelReader {
private long row;// 行
private List<Cell> cells = new ArrayList<Cell>();//列
public long getRow() {
return row;
}
public void setRow(long row) {
this.row = row;
}
public List<Cell> getCells() {
return cells;
}
public void setCells(Cell cell) {
this.cells.add(cell);
}
@Override
public String toString() {
return "ExcelReader [row=" + row + ", cells=" + cells + "]\r\n";
}
}
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/**
* 读操作升级版
*/
public class ReadExcelPlus {
@Test
public void test() throws Exception {
// 创建文件流
FileInputStream fStream = new FileInputStream(ExcelSuffix.PATH + "03明细" + ExcelSuffix.EXCEL03PREFIX);
// 调用读取表格的数据
List<List<ExcelReader>> readExcel = ReadExcel(fStream, 0, 1);
System.out.println(readExcel);// 输出打印
// 关闭流
fStream.close();
}
/**
* 读取excel
*
* @param fiStream 文件流
* @param sheetIndex 工作表索引;从哪个工作表中开始读
* @param rowIndex 行索引;需要读取标题传0;不要标题传1
* @return
* @throws Exception
*/
public static List<List<ExcelReader>> ReadExcel(FileInputStream fiStream, int sheetIndex,
int rowIndex) throws Exception {
List<List<ExcelReader>> excels = new ArrayList<List<ExcelReader>>();// 封装的对象
Workbook wk = new HSSFWorkbook(fiStream);// 创建工作薄并将文件流加载到内存中
int sheets = wk.getNumberOfSheets();// 获取所有工作表的个数
int sheetAt = 0;// 工作表下标索引
if (sheetIndex <= sheets)
sheetAt = sheetIndex;// 从第几个工作表开始
for (; sheetAt < sheets; sheetAt++) {// 循环工作表
Sheet sheet = wk.getSheetAt(sheetAt);
if (sheet.getPhysicalNumberOfRows() == 0)
continue; // 工作表为空,跳过本次循环进入下一次循环
List<ExcelReader> currentSheetExcels = new ArrayList<ExcelReader>();// 当前工作表的数据
if (sheet != null) {// 这里也可以判断一下工作表是否为空
int rows = sheet.getPhysicalNumberOfRows();// 获取行数获取工作表的行数
int i = 0;
if (rowIndex <= rows)
i = rowIndex;// 从第几行开始读,如果标题不要,可以传1过来
for (; i < rows; i++) {
Row row = sheet.getRow(i);// 获取行
int cells = row.getPhysicalNumberOfCells();// 获取当前行的所有列
ExcelReader er = new ExcelReader();// 工作表读取对象
er.setRow(i);// 设置行
for (int j = 0; j < cells; j++) {
Cell cell = row.getCell(j);// 获取每一个单元格
if (cell != null)
er.setCells(cell);// 设置列
}
if (er.getCells() != null && er.getCells().size() > 0) {// 判断列集合中是否有数据
currentSheetExcels.add(er);// 将数据加入到当前工作表中
}
}
}
excels.add(currentSheetExcels);
}
return excels;
}
}Excel写操作：通过自定义注解和反射实现
/**
* @interface<br/>
*
* @Target 表示我们的注解可以用在哪些地方
* ElementType.TYPE 类/接口
* ElementType.FIELD 字段声明
* ElementType.METHOD 方法声明
* ElementType.PACKAGE 包
*
* @Retention 表示我们自定义的注解在什么阶段还有效
* RetentionPolicy.RUNTIME 运行级别
* RetentionPolicy.CLASS 字节码级别
* RetentionPolicy.SOURCE 源码级别
*
* 运行级别: RUNTIME > CLASS > SOURCE
*/
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface ExcelHead {
String value();
int[] freeze() default {};
}
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@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface ExcelField {
String value();
}
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/**
* 学生类
*/
@ExcelHead(value = "学生信息",freeze = {0,3})
public class Student {
@ExcelField(value = "姓名")
private String name;
@ExcelField(value = "性别")
private String gender;
@ExcelField(value = "手机号码")
private String tel;
@ExcelField(value = "生日")
private String birthday;
@ExcelField(value = "年龄")
private int age;
@ExcelField(value = "地址")
private String address;
@ExcelField(value = "真假")
private boolean flag;
//构造方法、getter、setter、toString方法省略
}
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/**
* 测试数据初始化以及测试
*/
public class ExcelWrite {
List<Student> list = Arrays.asList(new Student("王祖贤", "女", "18763372970", "1992-05-21", 18, "HK", false),
new Student("陈乔恩", "女", "18763372768", "1991-05-21", 18, "TW", true),
new Student("黄蓉", "女", "18863372970", "1990-05-21", 18, "HK", false));
@Test
public void test() throws Exception {
Class<Student> clazz = Student.class;
String sheetName = clazz.getName();
ExcelHead excelHead = clazz.getAnnotation(ExcelHead.class);
sheetName = excelHead.value();
Workbook wb = new XSSFWorkbook();// 创建工作薄
Sheet sheet = wb.createSheet(sheetName);// 创建工作表
Field[] fields = clazz.getDeclaredFields();// 获取类中声明的属性
Row titleRow = sheet.createRow(0);// 创建标题行
for (int i = 0; i < fields.length; i++) {
ExcelField excelField = fields[i].getAnnotation(ExcelField.class);// 获取注解内容
Cell cell = titleRow.createCell(i);// 创建单元格
cell.setCellValue(excelField.value());// 设置值
}
String fieldName = null;
String getMethodName = null;
Object value = null;
for (int i = 0; i < list.size(); i++) {
Row row = sheet.createRow(i + 1);
for (int j = 0; j < fields.length; j++) {
Cell cell = row.createCell(j);
fieldName = fields[j].getName();//字段名称
getMethodName = "get" + fieldName.substring(0, 1).toUpperCase()
+ fieldName.substring(1);
Method getMethod = clazz.getMethod(getMethodName, new Class[]{});
value = getMethod.invoke(list.get(i), new Object[] {});
//判断类型,然后做相应的转换
if(value instanceof Boolean){
cell.setCellValue((Boolean)value);
}else {
cell.setCellValue(value.toString());
}
}
}
FileOutputStream fis = new FileOutputStream(ExcelSuffix.PATH + sheetName + ExcelSuffix.EXCEL07PREFIX);
wb.write(fis);
fis.close();
}
}
加油吧！
代码
