POI

读取Excel文件：
把poi-3.1-FINAL.jar 包导入项目，然后创建一个类，代码如下：
package demo.excel;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import org.apache.poi.hssf.eventusermodel.HSSFRequest;
import org.apache.poi.hssf.model.Sheet;
import org.apache.poi.hssf.model.Workbook;
import ermodel.HSSFCell;
import ermodel.HSSFRow;
import ermodel.HSSFSheet;
import ermodel.HSSFWorkbook;
import org.apache.poi.poifs.filesystem.POIFSFileSystem;
public class ExcelDemo {
public static void main(String[] args) {
File f = new File("f:/aa.xls");
if (f.exists()) {
// read
try {
InputStream fis = new FileInputStream(f);
//如何取得Excel的操作对象
POIFSFileSystem poifs = new POIFSFileSystem(fis);
//HSSFWorkbook 对象，是我们最想得到的对象。

HSSFWorkbook wb = new HSSFWorkbook(poifs);
List retList = new ArrayList();
System.out.println("此文件中表的数量是: " + wb.getNumberOfSheets());
HSSFSheet s = wb.getSheetAt(0);
System.out.println("表的对象是: "+s);
//wb.getNumberOfSheets():取得sheet的数目
for (int h = 0; h < wb.getNumberOfSheets(); ++h) {
System.out.println("sheet表的数量是："+wb.getNumberOfSheets());
List list = new ArrayList();
//根据index取得sheet对象,有了Sheet就相当于取得了一张表一样。

HSSFSheet sheet = wb.getSheetAt(h);
//取得有效的行数
int rowcount = sheet.getLastRowNum();
rowcount++;
System.out.print("第" + h + "张表: 行数= " + rowcount);
int colcount = 0;
for (int i = 0; i < rowcount; ++i) {
//根据index取得行对象,有了行对象，就可以取得每一个单元对象
HSSFRow row = sheet.getRow(i);
if (row == null)
continue;
if (colcount == 0) {
//知道一个行有多少个单元
colcount = row.getLastCellNum();
System.out.println(", 列数= " + colcount);
}
String[] fieldValue = new String[colcount];
for (short j = 0; j < colcount; ++j) {
//取得一个单元对象
HSSFCell cell = row.getCell(j);
// fieldValue[j] = getCellStringValue(cell);
if(cell!=null){
//取得单元的值,此处仅以字符串为例
System.out.println("单元格内容: "+cell.getStringCellValue());
}
//取得单元格的注释
//System.out.println("cell is : " +cell.getCellComment());
}
list.add(fieldValue);
}
retList.add(list);
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
导出Excel文件：
把poi-3.1-FINAL.jar 包导入项目，然后创建一个类，代码如下：
较好的官方便用说明地址
/spreadsheet/quick-guide.html#NewWorkbook package demo.excel;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import ermodel.HSSFRow;
import ermodel.HSSFSheet;
import ermodel.HSSFWorkbook;
public class XLSDemo {
public static void main(String[] args) {
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("new sheet");
FileOutputStream fileOut;
// Create a row and put some cells in it. Rows are 0 based.
HSSFRow row1 = sheet.createRow((short)0);
// Create a cell and put a value in it.
row1.createCell((short) 0).setCellValue(13);
row1.createCell((short) 1).setCellValue(12);
row1.createCell((short) 2).setCellValue(1.2008);
row1.createCell((short) 3).setCellValue(true);
try {
f ileOut = new FileOutputStream("F:/book.xls");
w b.write(fileOut);
f ileOut.close();
} catch (FileNotFoundException e) { S ystem.out.println("文件没有找到!");
e.printStackTrace();
} catch (IOException e) {
S ystem.out.println("IO异常!");
e.printStackTrace();
}
}
}。