poi 生成excel文件.xls或者.xls實例，包括日期寫入處理

import java.io.File;
import java.io.FileOutputStream;
import java.util.Date;

import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFDataFormat;
import org.apache.poi.hssf.usermodel.HSSFFont;
import org.apache.poi.hssf.util.HSSFColor;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.Font;
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.xssf.usermodel.XSSFWorkbook;

public class ExportExcel {
	
<span style="white-space:pre">	</span>private String excelPath = "E://haha.xlsx";
	 
    public static void main(String[] args) throws Exception{
    	ExportExcel excel = new ExportExcel();
        if(excel.createExcelFile()) {
            System.out.println("data.xlsx is created successfully.");
        }
    }
    public boolean createExcelFile() {
   	 int flag=0;
        boolean isCreateSuccess = false;
        Workbook workbook = null;
        try {
            workbook = new XSSFWorkbook();
        }catch(Exception e) {
            System.out.println("It cause Error on CREATING excel workbook: ");
            e.printStackTrace();
        }
        if(workbook != null) {
            Sheet sheet = workbook.createSheet("testdata");
            Row row0 = sheet.createRow(0);
            row0.setHeight((short)1000);//設置單元格寬和高
            sheet.setColumnWidth((short) 0, (short) 250);
            for(int i = 0; i < 13; i++) {
                Cell cell_1 = row0.createCell(i, Cell.CELL_TYPE_STRING);
                flag=0;
                CellStyle style = getStyle(workbook,flag,0);
                cell_1.setCellStyle(style);
                //此處是用來設置第一行標題
                switch (i) {
					case 0:
						cell_1.setCellValue("主題(Subject)");
						break;
					case 1:
						cell_1.setCellValue("用例引入ID");
						break;
					case 2:
						cell_1.setCellValue("用例修改狀態");
						break;
					case 3:
						cell_1.setCellValue("用例名稱");
						break;
					case 4:
						cell_1.setCellValue("用例等級");
						break;
					case 5:
						cell_1.setCellValue("預置條件");
						break;
					case 6:
						cell_1.setCellValue("操作步驟");
						break;
					case 7:
						cell_1.setCellValue("預期結果");
						break;
					case 8:
						cell_1.setCellValue("註釋");
						break;
					case 9:
						cell_1.setCellValue("設計者");
						break;
					case 10:
						cell_1.setCellValue("用例修改者");
						break;
					case 11:
						cell_1.setCellValue("用例編寫時間");
						break;
					case 12:
						cell_1.setCellValue("用例修改時間");
						break;
             }
                sheet.autoSizeColumn(i);
            }
            
            for (int rowNum = 1; rowNum < 20; rowNum++) {
                Row row = sheet.createRow(rowNum);
                row.setHeight((short)1500);
                for(int i = 0; i < 13; i++) {
               	 flag=1;
               	 CellStyle style = getStyle(workbook,flag,i);
		            Cell cell = row.createCell(i, Cell.CELL_TYPE_STRING);
		            cell.setCellStyle(style);
		            switch (i) {
						case 0:
							cell.setCellValue("hhh");
							break;
						case 1:
							cell.setCellValue(1212);
							break;
						case 2:
							cell.setCellValue("qqq");
							break;
						case 3:
							cell.setCellValue("dddd");
							break;
						case 4:
							cell.setCellValue("level_2");
							break;
						case 5:
							cell.setCellValue("ssss");
							break;
						case 6:
							cell.setCellValue("sss");
							break;
						case 7:
							cell.setCellValue("ggg");
							break;
						case 8:
							cell.setCellValue("hhh");
							break;
						case 9:
							cell.setCellValue("jjj");
							break;
						case 10:
							cell.setCellValue("kkjl");
							break;
						case 11:
							cell.setCellValue(new Date());
							break;
						case 12:
							cell.setCellValue(new Date());
							break;
						}
                }
            }
            try {
                FileOutputStream outputStream = new FileOutputStream(excelPath);
                workbook.write(outputStream);
                outputStream.flush();
                outputStream.close();
                isCreateSuccess = true;
            } catch (Exception e) {
                System.out.println("It cause Error on WRITTING excel workbook: ");
                e.printStackTrace();
            }
        }
        File sss = new File(excelPath);
        System.out.println(sss.getAbsolutePath());
        return isCreateSuccess;
    }
    private CellStyle getStyle(Workbook workbook,int flag,int i){//flag是用來判斷是否是標題，從而來設置不同的標題，i是用來判斷是某列，來對某列的樣式進行設定
        CellStyle style = workbook.createCellStyle();
        style.setAlignment(CellStyle.ALIGN_CENTER); 
        style.setVerticalAlignment(CellStyle.VERTICAL_CENTER);
        style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);//給單元格設置底色，如果要給單元格設置顏色，必須先設置底色才行，否則顏色出不來
        if(flag==0){
       	 style.setFillForegroundColor(HSSFColor.GREY_25_PERCENT.index);//設置標題顏色
        }else {
       	 style.setFillForegroundColor(HSSFColor.PALE_BLUE.index);//設置正文背景色
		}
        
        if(i==11||i==12){//因爲第12行13行是要寫入日期，所要預先設置日期格式，然後直接設置，注意是date類型
			style.setDataFormat(HSSFDataFormat.getBuiltinFormat("m/d/yy"));//設置日期格式
		}
        
        // 設置單元格字體
        Font headerFont = workbook.createFont(); // 字體
        headerFont.setFontHeightInPoints((short)14);
        if(flag==0){
       	 headerFont.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);//粗體顯示
        }
        headerFont.setFontName("宋體");
        style.setFont(headerFont);
        style.setWrapText(true);

        // 設置單元格邊框及顏色
        style.setBorderBottom(HSSFCellStyle.BORDER_THIN); //下邊框
        style.setBorderLeft(HSSFCellStyle.BORDER_THIN);//左邊框
        style.setBorderTop(HSSFCellStyle.BORDER_THIN);//上邊框
        style.setBorderRight(HSSFCellStyle.BORDER_THIN);//右邊框
        style.setWrapText(true);
        return style;
    }

}