Poi即poor object interface之意，是poi项目组对微软封闭的office文件格式（接口）的称谓！
其中提供了对word和excel的java接口，用法非常简单，并且是完全免费的，对中文的支持也相当不错，下面是处理excel一个简单的实例：
package test;
import java.io.*;
import org.apache.poi.hssf.usermodel.*;
import org.apache.poi.poifs.filesystem.POIFSFileSystem;
public class Test {
public static void main(String[] args) {
try {
/**************创建一个xls文档*************/
HSSFWorkbook wb = new HSSFWorkbook();
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
HSSFSheet sheet = wb.createSheet("new sheet");
HSSFRow row = sheet.createRow((short)0);
HSSFCell cell = row.createCell((short)0);
row.createCell((short)1);
row.createCell((short)2);
row.createCell((short)3);
row.createCell((short)4);
row.createCell((short)5);
cell.setCellValue("test_write!");
wb.write(fileOut);
fileOut.close();
/*************读取并修改xls文档***************/
POIFSFileSystem pfs=new POIFSFileSystem(new FileInputStream("workbook.xls"));
HSSFWorkbook hwb=new HSSFWorkbook(pfs);
HSSFSheet hs=hwb.getSheetAt(0);
HSSFRow hr=hs.getRow(0);
HSSFCellStyle style=hwb.createCellStyle();
style.setAlignment(style.ALIGN_CENTER);
HSSFFont hf=hwb.createFont();
hf.setFontName("楷体_GB2312");
style.setFont(hf);
HSSFCell cl=hr.getCell((short)2);
cl.setEncoding(cl.ENCODING_UTF_16);
cl.setCellStyle(style);
cl.setCellValue("test_modify! 测试\u2014\u2014编辑！");
FileOutputStream fos=new FileOutputStream("workbook.xls");
hwb.write(fos);
fos.flush();
fos.close();
}
catch (Exception ex) {
ex.printStackTrace();
}
}
}