Java生成Excel文件（xls格式）

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Calendar;
import java.util.Date;
import jxl.Workbook;
import jxl.format.Colour;
import jxl.format.UnderlineStyle;
import jxl.write.Boolean;
import jxl.write.DateFormats;
import jxl.write.DateTime;
import jxl.write.Label;
import jxl.write.Number;
import jxl.write.WritableCellFormat;
import jxl.write.WritableFont;
import jxl.write.WritableSheet;
import jxl.write.WritableWorkbook;
import jxl.write.WriteException;

public class BuildExcel {
    public void createExcel(OutputStream os) throws WriteException,IOException {
        //创建工作薄
        WritableWorkbook workbook = Workbook.createWorkbook(os);
        //创建新的一页  ---sheet页命名 ； sheet页号
        WritableSheet sheet = workbook.createSheet("First Sheet", 0);
        //构造表头
        sheet.mergeCells(0, 0, 4, 0);//添加合并单元格，第一个参数