jxl，读写excel追加数据。

import java.io.File;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;

import jxl.Sheet;
import jxl.Workbook;
import jxl.read.biff.BiffException;
import jxl.write.Label;
import jxl.write.WritableSheet;
import jxl.write.WritableWorkbook;
import jxl.write.WriteException;
import jxl.write.biff.RowsExceededException;

 public class WriteExcel {

	private static SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");

	private static File hasFile;

	/**
	 * 同步操作，防止并发。
	 * 
	 * @param args
	 * @return
	 * @throws IOException
	 * @throws RowsExceededException
	 * @throws WriteException
	 */
	public synchronized static String[] write(String[] args)
			throws IOException, RowsExceededException, WriteException {

		// 文件路径
		// 判断文件是否存在，如果存在就不创建，追加，如果不存在则创建文件并追加。
		WritableWorkbook book = Workbook.createWorkbook(getHasFile());
		book.setProtected(true);
		// -- 第一个参数是Sheet名，第二个参数是Sheet下标
		// -- 下标是整数，只起标识作用，建立的时候会以create顺序建立，本例生成的EXCEL文件第一个Sheet是sheet1
		WritableSheet sheet = book.createSheet("第一页", 1);
		sheet.setColumnView(0, 20);
		sheet.setColumnView(1, 20);
		sheet.setColumnView(2, 5);
		sheet.setColumnView(3, 20);
		sheet.setColumnView(4, 20);
		sheet.setColumnView(5, 20);
		sheet.setColumnView(6, 20);
		sheet.setColumnView(7, 20);
		sheet.setColumnView(8, 20);
		sheet.getSettings().setProtected(true);
		sheet.getSettings().setPassword("xxxx");//设置密码
		String[] title = { "支付宝交易号", "订单号", "交易总金额", "商品名称/订单名称", "商品描述/订单备注",
				"买家支付宝账号", "交易状态", "sign", "交易时间" };
		for (int i = 0; i < title.length; i++) {
			Label lable = new Label(i, 0, title[i]);
			sheet.addCell(lable);
		}
		// 初次创建，写入一行。
		for (int i = 0; i < title.length; i++) {
			Label lable = new Label(i, 1, args[i]);
			sheet.addCell(lable);
		}
		// 每次写入数据时，写到最后一行。
		book.write();
		book.close();
		System.out.println("写入成功");
		return null;
	}

	/**
	 * 追加excel
	 * 
	 * @param args
	 * @throws IOException
	 * @throws BiffException
	 * @throws WriteException
	 * @throws RowsExceededException
	 */
	public static void addExcel(File file, String[] args) throws BiffException,
			IOException, RowsExceededException, WriteException {
		Workbook book = Workbook.getWorkbook(file);
		Sheet sheet = book.getSheet(0);
		// 获取行
		int length = sheet.getRows();
		System.out.println(length);
		WritableWorkbook wbook = Workbook.createWorkbook(file, book); // 根据book创建一个操作对象
		WritableSheet sh = wbook.getSheet(0);// 得到一个工作对象
		// 从最后一行开始加
		for (int i = 0; i < args.length; i++) {
			Label label = new Label(i, length, args[i]);
			sh.addCell(label);
		}
		wbook.write();
		wbook.close();
	}

	/**
	 * 判断文件是否已经写入
	 * 
	 * @param filename
	 * @return
	 */
	public static boolean filecheck(String filename) {
		boolean flag = false;
		File file = new File(filename);
		if (file.exists()) {
			flag = true;
		}
		setHasFile(file);
		return flag;
	}

	/**
	 * 不管神马类型，都转换成string
	 * 
	 * @param obj
	 * @return
	 */
	public static String converToString(Object obj) {
		return "";
	}

	public static void main(String[] args) throws RowsExceededException,
			WriteException, IOException, BiffException {
		String filepath = WriteExcel.class.getResource("/").getPath()
				+ sdf.format(new Date()) + ".xls";
		String[] str = { "20101020102032032", "2012203203232032032", "50",
				"100元朗识币", "这个订单没有备注", "[e-mail]", "STATU_SUCCESS",
				"ssdhfksdhfksdjhfkshdsdlfd", sdf.format(new Date()) };
		boolean has = WriteExcel.filecheck(filepath);
		// 如果存在
		if (has)
			addExcel(getHasFile(), str);
		else {
			write(str);
		}

	}

	/**
	 * @return the hasFile
	 */
	public static File getHasFile() {
		return hasFile;
	}

	/**
	 * @param hasFile
	 *            the hasFile to set
	 */
	public static void setHasFile(File hasFile) {
		WriteExcel.hasFile = hasFile;
	}

}

 

执行第一次，在common/classes下创建了一个yyyyMMd.xls的文件，写入2行数据。

再次执行，此文件数据追加一行。

可用来操作数据量不大的数据保存。

方便下载查看以及储存。

缺点：追加数据的时候读取原来的文件作为副本然后新建一个工作对象，数据量大会导致内存溢出。

csv也不错，可以研究一下，代码：

 

import java.io.BufferedWriter;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;

import jxl.Cell;
import jxl.Sheet;
import jxl.Workbook;

/**
 * Simple demo class which uses the api to present the contents
 * of an excel 97 spreadsheet as comma separated values, using a workbook
 * and output stream of your choice
 */
public class CSV
{
  /**
   * Constructor
   *
   * @param w The workbook to interrogate
   * @param out The output stream to which the CSV values are written
   * @param encoding The encoding used by the output stream.  Null or 
   * unrecognized values cause the encoding to default to UTF8
   * @param hide Suppresses hidden cells
   * @exception java.io.IOException
   */
  public CSV(Workbook w, OutputStream out, String encoding, boolean hide)
    throws IOException
  {
    if (encoding == null || !encoding.equals("UnicodeBig"))
    {
      encoding = "UTF8";
    }

    try
    {
      OutputStreamWriter osw = new OutputStreamWriter(out, encoding);
      BufferedWriter bw = new BufferedWriter(osw);
      
      for (int sheet = 0; sheet < w.getNumberOfSheets(); sheet++)
      {
        Sheet s = w.getSheet(sheet);

        if (!(hide && s.getSettings().isHidden()))
        {
          bw.write("*** " + s.getName() + " ****");
          bw.newLine();
          
          Cell[] row = null;
          
          for (int i = 0 ; i < s.getRows() ; i++)
          {
            row = s.getRow(i);
            
            if (row.length > 0)
            {
              if (!(hide && row[0].isHidden()))
              {
                bw.write(row[0].getContents());
                // Java 1.4 code to handle embedded commas
                // bw.write("\"" + row[0].getContents().replaceAll("\"","\"\"") + "\"");
              }
              
              for (int j = 1; j < row.length; j++)
              {
                bw.write(',');
                if (!(hide && row[j].isHidden()))
                {
                  bw.write(row[j].getContents());
                  // Java 1.4 code to handle embedded quotes
                  //  bw.write("\"" + row[j].getContents().replaceAll("\"","\"\"") + "\"");
                }
              }
            }
            bw.newLine();
          }
        }
      }
      bw.flush();
      bw.close();
    }
    catch (UnsupportedEncodingException e)
    {
      System.err.println(e.toString());
    }
  }
}