POI-Excel写
导入依赖
<dependencies>
<!--xlsx(03)-->
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi</artifactId>
<version>3.9</version>
</dependency>
<!--xlsx(07)-->
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>3.9</version>
</dependency>
<!--日期格式化工具-->
<dependency>
<groupId>joda-time</groupId>
<artifactId>joda-time</artifactId>
<version>2.10.1</version>
</dependency>
String path ="C:\\Users\\2020\\IdeaProjects\\SpringFuXi\\poi\\src\\main\\java\\org\\example";
@Test
public void testWrite03() throws IOException {
//1.创建一个工作簿
Workbook workbook = new HSSFWorkbook();
//2.创建一个工作表
Sheet sheet = workbook.createSheet("统计表");
//3.创建一个行
Row row1 = sheet.createRow(0);
//4.创建一个单元格
Cell cell = row1.createCell(0);
cell.setCellValue("今日新增");
Cell cell1 = row1.createCell(1);
cell1.setCellValue(666);
//创建第二行
Row row2 = sheet.createRow(1);
Cell cell2 = row2.createCell(0);
cell2.setCellValue("统计时间");
Cell cell3 = row2.createCell(1);
cell3.setCellValue(new DateTime().toString("yyyy-MM-dd HH-mm-ss"));
//生成一张表 03版本就是使用xls结尾
FileOutputStream fileOutputStream = new FileOutputStream(path + "统计表03.xls");
workbook.write(fileOutputStream);
fileOutputStream.close();
System.out.println("生成完毕");
}
@Test
public void testWrite07() throws IOException {
//1.创建一个工作簿
Workbook workbook = new XSSFWorkbook();
//2.创建一个工作表
Sheet sheet = workbook.createSheet("统计表");
//3.创建一个行
Row row1 = sheet.createRow(0);
//4.创建一个单元格
Cell cell = row1.createCell(0);
cell.setCellValue("今日新增");
Cell cell1 = row1.createCell(1);
cell1.setCellValue(666);
//创建第二行
Row row2 = sheet.createRow(1);
Cell cell2 = row2.createCell(0);
cell2.setCellValue("统计时间");
Cell cell3 = row2.createCell(1);
cell3.setCellValue(new DateTime().toString("yyyy-MM-dd HH-mm-ss"));
//生成一张表 03版本就是使用xls结尾
FileOutputStream fileOutputStream = new FileOutputStream(path + "统计表07.xlsx");
workbook.write(fileOutputStream);
fileOutputStream.close();
System.out.println("07生成完毕");
}
注意对象的区别,文件后缀!
03 大文件写HSSF
缺点:最多只能处理65535行,否则会抛异常
优点:过程中写入缓存,不操作磁盘,最后一次性写入磁盘,速度快
@Test
public void bigData03() throws IOException {
long begin = System.currentTimeMillis();
Workbook workbook = new HSSFWorkbook();
Sheet sheet = workbook.createSheet();
for (int i = 0; i < 65536; i++) {
Row row = sheet.createRow(i);
for (int j = 0; j < 10; j++) {
Cell cell = row.createCell(j);
cell.setCellValue(j);
}
}
System.out.println("over");
FileOutputStream fileOutputStream = new FileOutputStream(path+"大文件写入03.xls");
workbook.write(fileOutputStream);
fileOutputStream.close();
long end = System.currentTimeMillis();
System.out.println((double) (end-begin)/1000);
}
07 大文件写XSSF
缺点:写数据速度非常慢,非常耗内存,也会发生内存溢出,如100万条
java.lang.IllegalArgumentException: Invalid row number (65536) outside allowable range (0..65535)
优点:可以写较大的数据量,如20万条
@Test
public void bigData07() throws IOException {
long begin = System.currentTimeMillis();
Workbook workbook = new XSSFWorkbook();
Sheet sheet = workbook.createSheet();
for (int i = 0; i < 65537; i++) {
Row row = sheet.createRow(i);
for (int j = 0; j < 10; j++) {
Cell cell = row.createCell(j);
cell.setCellValue(j);
}
}
System.out.println("over");
FileOutputStream fileOutputStream = new FileOutputStream(path+"大文件写入07.xlsx");
workbook.write(fileOutputStream);
fileOutputStream.close();
long end = System.currentTimeMillis();
System.out.println((double) (end-begin)/1000);
}
大文件写SXSSF
优点:可以写非常大的数据量,如100万条甚至更多条,写数据速度快,占用更少内存
注意:
过程中会产生临时文件,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
如果像自定义内存中数据的数量,可以使用new SXSSWorkBook(数量)
SXSSFWorkbook来自官方的解释:实现"Big GridDemo"策略的流式XSSFWorkbook版本,这允许写入非常大的文件而不会耗尽内存,因为任何时候只有可配置的行部分被保存在内存中.
请注意,仍然可能会消耗大量内存,这些内存基于您正在使用的功能,例如合并区域,注释...仍只存储在内存中,因此如果广泛使用,可能需要大量内存.
@Test
public void bigData07S() throws IOException {
long begin = System.currentTimeMillis();
Workbook workbook = new SXSSFWorkbook();
Sheet sheet = workbook.createSheet();
for (int i = 0; i < 65537; i++) {
Row row = sheet.createRow(i);
for (int j = 0; j < 10; j++) {
Cell cell = row.createCell(j);
cell.setCellValue(j);
}
}
System.out.println("over");
FileOutputStream fileOutputStream = new FileOutputStream(path+"大文件写入07S.xlsx");
workbook.write(fileOutputStream);
fileOutputStream.close();
//删除临时文件
((SXSSFWorkbook)workbook).dispose();
long end = System.currentTimeMillis();
System.out.println((double) (end-begin)/1000);
}
POI-excel读
03版本
@Test
public void testRead03() throws IOException {
//获取文件流
FileInputStream fis = new FileInputStream(path+"example统计表03.xls");
//1.创建一个工作簿,使用excel能操作的这边他都可以操作
Workbook workbook = new HSSFWorkbook(fis);
//得到表
Sheet sheetAt = workbook.getSheetAt(0);
//得到列
Row row = sheetAt.getRow(1);
//得到行
Cell cell = row.getCell(0);
//读取值的时候一定要注意读取类型
System.out.println(cell.getStringCellValue());
fis.close();
}
07版本
@Test
public void testRead07() throws IOException {
//获取文件流
FileInputStream fis = new FileInputStream(path+"example统计表07.xlsx");
//1.创建一个工作簿,使用excel能操作的这边他都可以操作
Workbook workbook = new XSSFWorkbook(fis);
//得到表
Sheet sheetAt = workbook.getSheetAt(0);
//得到列
Row row = sheetAt.getRow(0);
//得到行
Cell cell = row.getCell(0);
//读取值的时候一定要注意读取类型
System.out.println(cell.getStringCellValue());
fis.close();
}
注意获取值的类型即可
读取不同的数据类型(比较麻烦)
@Test
public void testCellType() throws IOException {
//获取文件流
FileInputStream fis = new FileInputStream(path+"example统计表03.xls");
//1.创建一个工作簿,使用excel能操作的这边他都可以操作
Workbook workbook = new HSSFWorkbook(fis);
//获取标题内容
Sheet sheetAt = workbook.getSheetAt(0);
//获取标题内容
Row title = sheetAt.getRow(0);
if (title!=null){
int cellCount = title.getPhysicalNumberOfCells(); //获取第一行的元素个数
for (int i = 0; i < cellCount; i++) {
Cell cell = title.getCell(i);
if (cell != null) {
CellStyle cellType = cell.getCellStyle();
String stringCellValue = cell.getStringCellValue();
System.out.print(stringCellValue+"|");
}
}
System.out.println();
}
//获取表中内容
int rowCount = sheetAt.getPhysicalNumberOfRows();
for (int i = 1; i < rowCount ; i++) {
Row rowData = sheetAt.getRow(i);
if (rowData != null) {
//读取列
int cellCount = title.getPhysicalNumberOfCells();
for (int j = 0; j < cellCount; j++) {
System.out.print("["+(i+1)+"-"+(j+1)+"]");
Cell cell = rowData.getCell(j);
//匹配列的数据类型
if (cell!=null){
int cellType = cell.getCellType();
String cellValue = "";
switch (cellType){
case Cell.CELL_TYPE_STRING: //字符串
System.out.print("[String]");
cellValue = cell.getStringCellValue();
break;
case Cell.CELL_TYPE_BOOLEAN: //布尔值
System.out.print("[Boolean]");
cellValue = String.valueOf(cell.getBooleanCellValue());
break;
case Cell.CELL_TYPE_BLANK: //空白
System.out.print("[null]");
break;
case Cell.CELL_TYPE_NUMERIC: //数字
System.out.print("[CELL_TYPE_NUMERIC]");
if (HSSFDateUtil.isCellDateFormatted(cell)){ //日期
System.out.print("日期");
Date date = cell.getDateCellValue();
cellValue = new DateTime(date).toString("yyyy-MM-dd");
}else {
//如果不是日期格式,防止数字过长,
System.out.print("普通数字");
cell.setCellType(HSSFCell.CELL_TYPE_NUMERIC);
cellValue = String.valueOf(cell.getNumericCellValue());
}
break;
case Cell.CELL_TYPE_ERROR: //错误
System.out.print("[数据类型错误]");
break;
}
System.out.println(cellValue);
}
}
}
}
fis.close();
}
计算公式
@Test
public void testFormula() throws IOException {
FileInputStream fis = new FileInputStream(path+"example统计表03.xls");
Workbook workbook = new HSSFWorkbook(fis);
Sheet sheetAt = workbook.getSheetAt(0);
Row row = sheetAt.getRow(4);
Cell cell = row.getCell(0);
//拿到计算公司 eval
FormulaEvaluator hssfFormulaEvaluator = new HSSFFormulaEvaluator((HSSFWorkbook) workbook);
//输出单元内容
int cellType = cell.getCellType();
switch (cellType){
case Cell.CELL_TYPE_FORMULA: //公式
String cellFormula = cell.getCellFormula();
System.out.println(cellFormula);
//计算
CellValue evaluate = hssfFormulaEvaluator.evaluate(cell);
String cellValue = evaluate.formatAsString();
System.out.println(cellValue);
break;
}
}
EasyExcel
1.导入依赖
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>easyexcel</artifactId>
<version>2.2.0-beta2</version>
</dependency>
写入
public void simpleWrite(){
String path ="C:\\Users\\2020\\IdeaProjects\\SpringFuXi\\poi\\src\\main\\java\\org\\example\\";
String fileName = path+"EasyTest.xlsx";
//这里需要指定写用那个class去写,然后写到第一个sheet,名字为模板,然后文件流会自动关闭
//write(fileName,格式类)
//sheet(表明)
//doWrite(数据)
EasyExcel.write(fileName,DemoData.class).sheet("模板").doWrite(data());
}