使用POI读写Excel文件

package com.jadyer.demo;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.ss.usermodel.WorkbookFactory;

/**
 * POI下载地址为http://poi.apache.org/
 * 这里要用到poi-3.9-20121203.jar和poi-ooxml-3.9-20121203.jar
 * @create Jul 9, 2013 7:54:34 PM
 * @author 玄玉<http://blog.csdn.net/jadyer>
 */
public class POIDemo {
	public static void writeExcel() throws IOException{
		//创建一个Excel(or new XSSFWorkbook())
		Workbook wb = new HSSFWorkbook();
		//创建表格
		Sheet sheet = wb.createSheet("测试Sheet_01");
		//创建行
		Row row = sheet.createRow(0);
		//设置行高
		row.setHeightInPoints(30);
		//创建样式
		CellStyle cs = wb.createCellStyle();
		cs.setAlignment(CellStyle.ALIGN_CENTER);
		cs.setVerticalAlignment(CellStyle.VERTICAL_CENTER);
		cs.setBorderBottom(CellStyle.BORDER_DOTTED); 
		cs.setBorderLeft(CellStyle.BORDER_THIN); 
		cs.setBorderRight(CellStyle.BORDER_THIN);
		cs.setBorderTop(CellStyle.BORDER_THIN);
		//创建单元格
		Cell cell = row.createCell(0);
		//设置单元格样式
		cell.setCellStyle(cs);
		//设置单元格的值
		cell.setCellValue("序号");
		cell = row.createCell(1);
		cell.setCellStyle(cs);
		cell.setCellValue("用户");
		row = sheet.createRow(1);
		cell = row.createCell(0);
		cell.setCellValue("1");
		cell = row.createCell(1);
		cell.setCellValue("张起灵");
		FileOutputStream fos = new FileOutputStream("D:/测试的Excel.xls");
		wb.write(fos);
		if(null != fos){
			fos.close();
		}
	}

	public static void readExcel() throws InvalidFormatException, IOException{
		long startTime = System.currentTimeMillis();
		int count = 0;
		//老版本POI是使用这种方式创建Workbook的,新版本中可以使用WorkbookFactory,它能自动根据文档的类型打开一个Excel
		//Workbook wb = new HSSFWorkbook(new FileInputStream("D:/5月业务定制对账文件汇总.xls"));
		Workbook wb = WorkbookFactory.create(new File("D:/5月业务定制对账文件汇总.xls"));
		//获取Excel中的某一个数据表..也可以通过Sheet名称来获取,即Workbook.getSheet("定制对账文件")
		Sheet sheet = wb.getSheetAt(0);
		Row row = null;
		Cell cell = null;
		//获取Excel的总行数:Sheet.getLastRowNum()+1(需要+1)
		for(/*int i=0*/ int i=sheet.getFirstRowNum(); i<sheet.getLastRowNum()+1; i++){
			//获取数据表里面的某一行
			row = sheet.getRow(i);
			//获取Excel的总列数:Row.getLastCellNum()(不用+1)
			for(/*int j=0*/ int j=row.getFirstCellNum(); j<row.getLastCellNum(); j++){
				//获取一行中的一个单元格
				String cellData = getCellValue(row.getCell(j)).trim();
				System.out.print(j == 0 ? count + 1 + "----" + cellData + "----" : cellData + "----");
			}
			count++;
			//打印完一行的数据之后,再输入一个空行
			System.out.println();
		}
		long endTime = System.currentTimeMillis();
		long useTime = endTime - startTime;
		System.out.println("导入文件完毕,导入数据[" + count + "]条,耗时" + useTime + "ms");
		String suffix = String.valueOf(useTime % 1000);
		while(suffix.endsWith("0")){
			suffix = suffix.substring(0, suffix.length()-1);
		}
		System.out.println("导入文件完毕,导入数据[" + count + "]条,耗时" + (useTime/1000) + "." + suffix + "秒");
	}
	
	/**
	 * 使用for-each循环来读取Excel
	 */
	public static void readExcelUseForeach() throws InvalidFormatException, IOException {
		for(Row row : WorkbookFactory.create(new File("D:/5月业务定制对账文件汇总.xls")).getSheetAt(0)){
			for(Cell cell : row){
				System.out.print(getCellValue(cell) + "----");
			}
			System.out.println();
		}
	}
	
	/**
	 * 获取单元格内的数据值
	 */
	private static String getCellValue(Cell cell){
		String str = null;
		switch (cell.getCellType()) {
		case Cell.CELL_TYPE_BLANK:
			str = ""; break;
		case Cell.CELL_TYPE_BOOLEAN:
			str = String.valueOf(cell.getBooleanCellValue()); break;
		case Cell.CELL_TYPE_FORMULA:
			str = String.valueOf(cell.getCellFormula()); break;
		case Cell.CELL_TYPE_NUMERIC:
			str = String.valueOf(cell.getNumericCellValue()); break;                //不要科学计数法
			str = new DecimalFormat("0").format(cell.getNumericCellValue()); break; //处理科学计数法
		case Cell.CELL_TYPE_STRING:
			str = cell.getStringCellValue(); break;
		default:
			str = null;
			break;
		}
		return str;
	}
}