最近在做项目的过程中需要将页面信息转换成excel表格输出，在多方面选择之下，最后使用了开源框架poi，使用过程中遇到过一些问题和总结了一些经验，记录下来，方便日后查阅。
一、导入jar包
要使用一个框架，首先要导入相应的jar包，poi的jar包去网上搜索就可以了，因为本人是使用Maven构建的项目，所以将pom文件中的引用贴出：
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi</artifactId>
<version>3.9</version>
</dependency>
导入jar包之后，便可以在程序中使用poi了
二、简单使用
首先我们看几个简单使用poi的例子，然后从例子中解析使用poi需要用到的类与对象：
1.创建工作簿 (WORKBOOK)
HSSFWorkbook wb = new HSSFWorkbook();
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
2.创建工作表（SHEET）
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet1 = wb.createSheet("new sheet");
HSSFSheet sheet2 = wb.createSheet("second sheet");
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
3.创建单元格(CELL)
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("new sheet");
// Create a row and put some cells in it. Rows are 0 based.
HSSFRow row = sheet.createRow((short)0);
// Create a cell and put a value in it.
HSSFCell cell = row.createCell((short)0);
cell.setCellValue(1);
// Or do it on one line.
row.createCell((short)1).setCellValue(1.2);
row.createCell((short)2).setCellValue("This is a string");
row.createCell((short)3).setCellValue(true);
// Write the output to a file
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
4.创建指定单元格式的单元格
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("new sheet");
// Create a row and put some cells in it. Rows are 0 based.
HSSFRow row = sheet.createRow((short)0);
// Create a cell and put a date value in it. The first cell is not styled
// as a date.
HSSFCell cell = row.createCell((short)0);
cell.setCellValue(new Date());
// we style the second cell as a date (and time). It is important to
// create a new cell style from the workbook otherwise you can end up
// modifying the built in style and effecting not only this cell but other cells.
HSSFCellStyle cellStyle = wb.createCellStyle();
cellStyle.setDataFormat(HSSFDataFormat.getBuiltinFormat("m/d/yy h:mm"));
cell = row.createCell((short)1);
cell.setCellValue(new Date());
cell.setCellStyle(cellStyle);
// Write the output to a file
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
5. 单元格的不同格式
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("new sheet");
HSSFRow row = sheet.createRow((short)2);
row.createCell((short) 0).setCellValue(1.1);
row.createCell((short) 1).setCellValue(new Date());
row.createCell((short) 2).setCellValue("a string");
row.createCell((short) 3).setCellValue(true);
row.createCell((short) 4).setCellType(HSSFCell.CELL_TYPE_ERROR);
// Write the output to a file
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
6.单元格的不通对齐方式
public static void main(String[] args)
throws IOException
{
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("new sheet");
HSSFRow row = sheet.createRow((short) 2);
createCell(wb, row, (short) 0, HSSFCellStyle.ALIGN_CENTER);
createCell(wb, row, (short) 1, HSSFCellStyle.ALIGN_CENTER_SELECTION);
createCell(wb, row, (short) 2, HSSFCellStyle.ALIGN_FILL);
createCell(wb, row, (short) 3, HSSFCellStyle.ALIGN_GENERAL);
createCell(wb, row, (short) 4, HSSFCellStyle.ALIGN_JUSTIFY);
createCell(wb, row, (short) 5, HSSFCellStyle.ALIGN_LEFT);
createCell(wb, row, (short) 6, HSSFCellStyle.ALIGN_RIGHT);
// Write the output to a file
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
}
/**
* Creates a cell and aligns it a certain way.
*
* @param wb the workbook
* @param row the row to create the cell in
* @param column the column number to create the cell in
* @param align the alignment for the cell.
*/
private static void createCell(HSSFWorkbook wb, HSSFRow row, short column, short align)
{
HSSFCell cell = row.createCell(column);
cell.setCellValue("Align It");
HSSFCellStyle cellStyle = wb.createCellStyle();
cellStyle.setAlignment(align);
cell.setCellStyle(cellStyle);
}
7.单元格的边框设置
Working with borders
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("new sheet");
// Create a row and put some cells in it. Rows are 0 based.
HSSFRow row = sheet.createRow((short) 1);
// Create a cell and put a value in it.
HSSFCell cell = row.createCell((short) 1);
cell.setCellValue(4);
// Style the cell with borders all around.
HSSFCellStyle style = wb.createCellStyle();
style.setBorderBottom(HSSFCellStyle.BORDER_THIN);
style.setBottomBorderColor(HSSFColor.BLACK.index);
style.setBorderLeft(HSSFCellStyle.BORDER_THIN);
style.setLeftBorderColor(HSSFColor.GREEN.index);
style.setBorderRight(HSSFCellStyle.BORDER_THIN);
style.setRightBorderColor(HSSFColor.BLUE.index);
style.setBorderTop(HSSFCellStyle.BORDER_MEDIUM_DASHED);
style.setTopBorderColor(HSSFColor.BLACK.index);
cell.setCellStyle(style);
// Write the output to a file
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
8.填充和颜色设置
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("new sheet");
// Create a row and put some cells in it. Rows are 0 based.
HSSFRow row = sheet.createRow((short) 1);
// Aqua background
HSSFCellStyle style = wb.createCellStyle();
style.setFillBackgroundColor(HSSFColor.AQUA.index);
style.setFillPattern(HSSFCellStyle.BIG_SPOTS);
HSSFCell cell = row.createCell((short) 1);
cell.setCellValue("X");
cell.setCellStyle(style);
// Orange "foreground", foreground being the fill foreground not the font color.
style = wb.createCellStyle();
style.setFillForegroundColor(HSSFColor.ORANGE.index);
style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
cell = row.createCell((short) 2);
cell.setCellValue("X");
cell.setCellStyle(style);
// Write the output to a file
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
9.合并单元格操作
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("new sheet");
HSSFRow row = sheet.createRow((short) 1);
HSSFCell cell = row.createCell((short) 1);
cell.setCellValue("This is a test of merging");
sheet.addMergedRegion(new Region(1,(short)1,1,(short)2));
// Write the output to a file
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
10.字体设置
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("new sheet");
// Create a row and put some cells in it. Rows are 0 based.
HSSFRow row = sheet.createRow((short) 1);
// Create a new font and alter it.
HSSFFont font = wb.createFont();
font.setFontHeightInPoints((short)24);
font.setFontName("Courier New");
font.setItalic(true);
font.setStrikeout(true);
// Fonts are set into a style so create a new one to use.
HSSFCellStyle style = wb.createCellStyle();
style.setFont(font);
// Create a cell and put a value in it.
HSSFCell cell = row.createCell((short) 1);
cell.setCellValue("This is a test of fonts");
cell.setCellStyle(style);
// Write the output to a file
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
11.自定义颜色
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet();
HSSFRow row = sheet.createRow((short) 0);
HSSFCell cell = row.createCell((short) 0);
cell.setCellValue("Default Palette");
//apply some colors from the standard palette,
// as in the previous examples.
//we'll use red text on a lime background
HSSFCellStyle style = wb.createCellStyle();
style.setFillForegroundColor(HSSFColor.LIME.index);
style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
HSSFFont font = wb.createFont();
font.setColor(HSSFColor.RED.index);
style.setFont(font);
cell.setCellStyle(style);
//save with the default palette
FileOutputStream out = new FileOutputStream("default_palette.xls");
wb.write(out);
out.close();
//now, let's replace RED and LIME in the palette
// with a more attractive combination
// (lovingly borrowed from freebsd.org)
cell.setCellValue("Modified Palette");
//creating a custom palette for the workbook
HSSFPalette palette = wb.getCustomPalette();
//replacing the standard red with freebsd.org red
palette.setColorAtIndex(HSSFColor.RED.index,
(byte) 153, //RGB red (0-255)
(byte) 0, //RGB green
(byte) 0 //RGB blue
);
//replacing lime with freebsd.org gold
palette.setColorAtIndex(HSSFColor.LIME.index, (byte) 255, (byte) 204, (byte) 102);
//save with the modified palette
// note that wherever we have previously used RED or LIME, the
// new colors magically appear
out = new FileOutputStream("modified_palette.xls");
wb.write(out);
out.close();
12.读和重写EXCEL文件
POIFSFileSystem fs =
new POIFSFileSystem(new FileInputStream("workbook.xls"));
HSSFWorkbook wb = new HSSFWorkbook(fs);
HSSFSheet sheet = wb.getSheetAt(0);
HSSFRow row = sheet.getRow(2);
HSSFCell cell = row.getCell((short)3);
if (cell == null)
cell = row.createCell((short)3);
cell.setCellType(HSSFCell.CELL_TYPE_STRING);
cell.setCellValue("a test");
// Write the output to a file
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
13.在EXCEL单元格中使用自动换行
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet s = wb.createSheet();
HSSFRow r = null;
HSSFCell c = null;
HSSFCellStyle cs = wb.createCellStyle();
HSSFFont f = wb.createFont();
HSSFFont f2 = wb.createFont();
cs = wb.createCellStyle();
cs.setFont( f2 );
//Word Wrap MUST be turned on
cs.setWrapText( true );
r = s.createRow( (short) 2 );
r.setHeight( (short) 0x349 );
c = r.createCell( (short) 2 );
c.setCellType( HSSFCell.CELL_TYPE_STRING );
c.setCellValue( "Use /n with word wrap on to create a new line" );
c.setCellStyle( cs );
s.setColumnWidth( (short) 2, (short) ( ( 50 * 8 ) / ( (double) 1 / 20 ) ) );
FileOutputStream fileOut = new FileOutputStream( "workbook.xls" );
wb.write( fileOut );
fileOut.close();
14.数字格式自定义
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("format sheet");
HSSFCellStyle style;
HSSFDataFormat format = wb.createDataFormat();
HSSFRow row;
HSSFCell cell;
short rowNum = 0;
short colNum = 0;
row = sheet.createRow(rowNum++);
cell = row.createCell(colNum);
cell.setCellValue(11111.25);
style = wb.createCellStyle();
style.setDataFormat(format.getFormat("0.0"));
cell.setCellStyle(style);
row = sheet.createRow(rowNum++);
cell = row.createCell(colNum);
cell.setCellValue(11111.25);
style = wb.createCellStyle();
style.setDataFormat(format.getFormat("#,##0.0000"));
cell.setCellStyle(style);
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
15.调整工作单位置
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("format sheet");
HSSFPrintSetup ps = sheet.getPrintSetup();
sheet.setAutobreaks(true);
ps.setFitHeight((short)1);
ps.setFitWidth((short)1);
// Create various cells and rows for spreadsheet.
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
16.设置打印区域
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("Sheet1");
wb.setPrintArea(0, "$A$1:$C$2");
//sets the print area for the first sheet
//Alternatively:
//wb.setPrintArea(0, 0, 1, 0, 0) is equivalent to using the name reference (See the JavaDocs for more details)
// Create various cells and rows for spreadsheet.
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
17.标注脚注
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("format sheet");
HSSFFooter footer = sheet.getFooter()
footer.setRight( "Page " + HSSFFooter.page() + " of " + HSSFFooter.numPages() );
// Create various cells and rows for spreadsheet.
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
18.使用方便的内部提供的函数
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet1 = wb.createSheet( "new sheet" );
// Create a merged region
HSSFRow row = sheet1.createRow( (short) 1 );
HSSFRow row2 = sheet1.createRow( (short) 2 );
HSSFCell cell = row.createCell( (short) 1 );
cell.setCellValue( "This is a test of merging" );
Region region = new Region( 1, (short) 1, 4, (short) 4 );
sheet1.addMergedRegion( region );
// Set the border and border colors.
final short borderMediumDashed = HSSFCellStyle.BORDER_MEDIUM_DASHED;
HSSFRegionUtil.setBorderBottom( borderMediumDashed,
region, sheet1, wb );
HSSFRegionUtil.setBorderTop( borderMediumDashed,
region, sheet1, wb );
HSSFRegionUtil.setBorderLeft( borderMediumDashed,
region, sheet1, wb );
HSSFRegionUtil.setBorderRight( borderMediumDashed,
region, sheet1, wb );
HSSFRegionUtil.setBottomBorderColor(HSSFColor.AQUA.index, region, sheet1, wb);
HSSFRegionUtil.setTopBorderColor(HSSFColor.AQUA.index, region, sheet1, wb);
HSSFRegionUtil.setLeftBorderColor(HSSFColor.AQUA.index, region, sheet1, wb);
HSSFRegionUtil.setRightBorderColor(HSSFColor.AQUA.index, region, sheet1, wb);
// Shows some usages of HSSFCellUtil
HSSFCellStyle style = wb.createCellStyle();
style.setIndention((short)4);
HSSFCellUtil.createCell(row, 8, "This is the value of the cell", style);
HSSFCell cell2 = HSSFCellUtil.createCell( row2, 8, "This is the value of the cell");
HSSFCellUtil.setAlignment(cell2, wb, HSSFCellStyle.ALIGN_CENTER);
// Write out the workbook
FileOutputStream fileOut = new FileOutputStream( "workbook.xls" );
wb.write( fileOut );
fileOut.close();
19.在工作单中移动行，调整行的上下位置
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("row sheet");
// Create various cells and rows for spreadsheet.
// Shift rows 6 - 11 on the spreadsheet to the top (rows 0 - 5)
sheet.shiftRows(5, 10, -5);
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
20.选种指定的工作单
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("row sheet");
sheet.setSelected(true);
// Create various cells and rows for spreadsheet.
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
21.工作单的放大缩小
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet1 = wb.createSheet("new sheet");
sheet1.setZoom(3,4); // 75 percent magnification
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
22.头注和脚注
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("new sheet");
HSSFHeader header = sheet.getHeader();
header.setCenter("Center Header");
header.setLeft("Left Header");
header.setRight(HSSFHeader.font("Stencil-Normal", "Italic") +
HSSFHeader.fontSize((short) 16) + "Right w/ Stencil-Normal Italic font and size 16");
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
三、重点介绍
一个excel文档必备的内容都有什么呢：
1、文档的名字和保存的位置。（文档以xls结尾）
2、sheet页，一个excel文档可以包括多个sheet页
3、行
4、单元格（有些单元格是合并的）
5、单元格样式(包括背景颜色、对其方式等)
HSSFWorkbook wb = new HSSFWorkbook(); //创建excel
HSSFSheet sheet1 = wb.createSheet("new sheet"); //创建多个sheet页
HSSFSheet sheet2 = wb.createSheet("second sheet");
HSSFCellStyle style = wb.createCellStyle(); //设置单元格背景颜色
style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
style.setFillForegroundColor(HSSFColor.YELLOW.index);
HSSFRow row = sheet1.createRow((short)0);//创建一行数据，
row.createCell((short)0).setCellValue(1); //给第一行数据赋值
row.createCell((short)1).setCellValue(1.2);
row.createCell((short)2).setCellValue("This is a string");
HSSFCell cell = row.createCell((short)3);
cell.setCellValue(true);
cell.setCellStyle(style);//设置单元格背景颜色
sheet1.addMergedRegion(new Region(0,(short)1,1,(short)1)); //合并单元格
HSSFCellStyle style_green = wb.createCellStyle(); //设置单元格背景颜色
style_green.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
style_green.setFillForegroundColor(HSSFColor.LIME.index);
style_green.setBorderBottom(HSSFCellStyle.BORDER_THIN); //下边框
style_green.setBorderLeft(HSSFCellStyle.BORDER_THIN);//左边框
style_green.setBorderTop(HSSFCellStyle.BORDER_THIN);//上边框
style_green.setBorderRight(HSSFCellStyle.BORDER_THIN);//右边框
style_green.setWrapText( true );//自动回车
style_green.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);//设置竖直方向居中
style_green.setAlignment(HSSFCellStyle.ALIGN_CENTER);//设置水平方向居中
sheet.setColumnWidth( (short) k, (short) ( ( 50 * 4 ) / ( (double) 1 / 20 ) ) );//设置单元格宽度
row1.setHeight((short) 0x220 );//设置行高度
页面弹出保存位置：
req.setCharacterEncoding("UTF-8");
resp.setCharacterEncoding("UTF-8");
resp.setContentType("application/x-download");
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss");
String filedisplay = sdf.format(new Date())+".xls";
filedisplay = URLEncoder.encode(filedisplay, "UTF-8");
resp.addHeader("Content-Disposition", "attachment;filename="+ filedisplay);
OutputStream out = resp.getOutputStream();
wb.write(out);
背景颜色：
HSSFColor.ROYAL_BLUE
HSSFColor.TEAL
HSSFColor.LIME
HSSFColor.PALE_BLUE
HSSFColor.AQUA
HSSFColor.GREEN
HSSFColor.TURQUOISE
HSSFColor.DARK_BLUE
HSSFColor.CORNFLOWER_BLUE
HSSFColor.OLIVE_GREEN
HSSFColor.WHITE
HSSFColor.LIGHT_TURQUOISE
HSSFColor.LEMON_CHIFFON
HSSFColor.LIGHT_GREEN
HSSFColor.BLUE
HSSFColor.DARK_RED
HSSFColor.CORAL
HSSFColor.RED
HSSFColor.LIGHT_YELLOW
HSSFColor.SKY_BLUE
HSSFColor.BROWN
HSSFColor.SEA_GREEN
HSSFColor.INDIGO
HSSFColor.MAROON
HSSFColor.GREY_80_PERCENT
HSSFColor.GREY_25_PERCENT
HSSFColor.DARK_GREEN
HSSFColor.YELLOW
HSSFColor.GOLD
HSSFColor.GREY_40_PERCENT
HSSFColor.DARK_TEAL
HSSFColor.PINK
HSSFColor.ORCHID
HSSFColor.LIGHT_BLUE
HSSFColor.LIGHT_CORNFLOWER_BLUE
HSSFColor.BLACK
HSSFColor.DARK_YELLOW
HSSFColor.VIOLET
HSSFColor.LAVENDER
HSSFColor.ROSE
HSSFColor.BLUE_GREY
HSSFColor.LIGHT_ORANGE
HSSFColor.ORANGE
HSSFColor.GREY_50_PERCENT
![[译]使用JMH进行微基准测试：不要猜，要测试！-HollisChuang's Blog](http://www.hollischuang.com/wp-content/uploads/2016/01/jmhproject1.png)
