JAVA对excel文件的处理方式

使用Apache的POI类对不同的excel文件对它们能够进行简单的读取操作：

1.读取excel，对于xls和xlsx有不同的类去对他们进行处理，个人理解的便是如果是xls类型的文件则在获取了文件的类型以后调用的类前面主要是HSSF，而xlsx格式的则调用XSSF类。

获取文件类型可以使用substring(filename.lastindexof(“.”));

下面便是读取文件的方法：

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import org.apache.poi.ss.usermodel.DataFormatter;
import org.apache.poi.ss.usermodel.DateUtil;
import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

public class ReadExcel{

private static XSSFWorkbook workbook;

public static void read(InputStream inputStream) throws IOException {
workbook = new XSSFWorkbook(inputStream);
for(int sheetIndex = 0;sheetIndex < workbook.getNumberOfSheets();sheetIndex++){
XSSFSheet sheet = workbook.getSheetAt(sheetIndex);
int num = 0;
System.out.println("sheet序号："+sheetIndex+",sheet名称："+workbook.getSheetName(sheetIndex));
for(int i = 0; i < sheet.getLastRowNum();i++){
XSSFRow row = sheet.getRow(i);
if (row == null) {
continue;
}
XSSFCell cell = row.getCell(i);
system.out.println(cell);
}
}
}

private static String getCellValue(XSSFCell cell){
String cellValue = "";
DataFormatter formatter = new DataFormatter();
if (cell != null) {
switch (cell.getCellType()) {
case XSSFCell.CELL_TYPE_NUMERIC:
if (DateUtil.isCellDateFormatted(cell)) {
cellValue = formatter.formatCellValue(cell);
} else {
double value = cell.getNumericCellValue();
int intValue = (int) value;
cellValue = value - intValue == 0 ? String.valueOf(intValue) : String.valueOf(value);
}
break;
case XSSFCell.CELL_TYPE_STRING:
cellValue = cell.getStringCellValue();
break;
case XSSFCell.CELL_TYPE_BOOLEAN:
cellValue = String.valueOf(cell.getBooleanCellValue());
break;
case XSSFCell.CELL_TYPE_FORMULA:
cellValue = String.valueOf(cell.getCellFormula());
break;
case XSSFCell.CELL_TYPE_BLANK:
cellValue = "";
break;
case XSSFCell.CELL_TYPE_ERROR:
cellValue = "";
break;
default:
cellValue = cell.toString().trim();
break;
}
}
return cellValue.trim();
}

public static void main(String[] args) {
InputStream inputStream = null;
try {
inputStream = new FileInputStream(new File("C:\\test.xlsx"));
read(inputStream);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (inputStream != null) {
inputStream.close();
workbook.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
}

Excel的写法则有与读取是类似的，只不过是个相反的过程。

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFRichTextString;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
/**
* POI入门 ：简单写出excel数据
* */
public class WriteExcelTest {
public static void write(OutputStream outputStream) throws IOException{
//初始一个workbook
HSSFWorkbook workbook = new HSSFWorkbook();
//创建一个表
HSSFSheet sheet = workbook.createSheet("firstSheet");
//创建行
HSSFRow row = sheet.createRow(0);
//创建单元格
HSSFCell cell = row.createCell(0);

cell.setCellValue(new HSSFRichTextString("hello POI"));
workbook.write(outputStream);
}

public static void main(String[] args) {
OutputStream outputStream = null;
try {
outputStream = new FileOutputStream(new File("E:\\helloPOI.xls"));
write(outputStream);
}catch (FileNotFoundException e) {
e.printStackTrace();
}catch (IOException e) {
e.printStackTrace();
}finally{
if(outputStream != null){
try {
outputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}