一．POI简介
Jakarta POI 是apache的子项目，目标是处理ole2对象。它提供了一组操纵Windows文档的Java API
目前比较成熟的是HSSF接口，处理MS Excel（97-2002）对象。它不象我们仅仅是用csv生成的没有格式的可以由Excel转换的东西，而是真正的Excel对象，你可以控制一些属性如sheet,cell等等。
二．HSSF概况
HSSF 是Horrible SpreadSheet Format的缩写，也即“讨厌的电子表格格式”。也许HSSF的名字有点滑稽，就本质而言它是一个非常严肃、正规的API。通过HSSF，你可以用纯Java代码来读取、写入、修改Excel文件。
HSSF 为读取操作提供了两类API：usermodel和eventusermodel，即“用户模型”和“事件-用户模型”。前者很好理解，后者比较抽象，但操作效率要高得多。
三．开始编码
1 ． 准备工作
要求:JDK 1.4+POI开发包
可以到 http://www.apache.org/dyn/closer.cgi/jakarta/poi/ 最新的POI工具包
2 ． EXCEL 结构
HSSFWorkbook excell 文档对象介绍
HSSFSheet excell的表单
HSSFRow excell的行
HSSFCell excell的格子单元
HSSFFont excell字体
HSSFName 名称
HSSFDataFormat 日期格式
在poi1.7中才有以下2项：
HSSFHeader sheet头
HSSFFooter sheet尾
和这个样式
HSSFCellStyle cell样式
辅助操作包括
HSSFDateUtil 日期
HSSFPrintSetup 打印
HSSFErrorConstants 错误信息表
3 ．具体用法实例 （采用 usermodel ）
如何读Excel
读取Excel文件时，首先生成一个POIFSFileSystem对象，由POIFSFileSystem对象构造一个HSSFWorkbook，该HSSFWorkbook对象就代表了Excel文档。下面代码读取上面生成的Excel文件写入的消息字串：
代码
POIFSFileSystem fs=newPOIFSFileSystem(new FileInputStream("d:/test.xls"));
HSSFWorkbook wb = new HSSFWorkbook(fs);
} catch (IOException e) {
e.printStackTrace();
}
HSSFSheet sheet = wb.getSheetAt(0);
HSSFRow row = sheet.getRow(0);
HSSFCell cell = row.getCell((short) 0);
String msg = cell.getStringCellValue();
POIFSFileSystem fs=newPOIFSFileSystem(new FileInputStream("d:/test.xls"));
HSSFWorkbook wb = new HSSFWorkbook(fs);
} catch (IOException e) {
e.printStackTrace();
}
HSSFSheet sheet = wb.getSheetAt(0);
HSSFRow row = sheet.getRow(0);
HSSFCell cell = row.getCell((short) 0);
String msg = cell.getStringCellValue();
如何写excel，
将excel的第一个表单第一行的第一个单元格的值写成“a test”。
代码
POIFSFileSystem fs =new POIFSFileSystem(new FileInputStream("workbook.xls"));
HSSFWorkbook wb = new HSSFWorkbook(fs);
HSSFSheet sheet = wb.getSheetAt(0);
HSSFRow row = sheet.getRow(0);
HSSFCell cell = row.getCell((short)0);
cell.setCellValue("a test");
// Write the output to a file
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();
4 ． 可参考文档
POI 主页：http://jakarta.apache.org/poi/，
初学者如何快速上手使用POI HSSF
http://jakarta.apache.org/poi/hssf/quick-guide.html 。
代码例子 http://blog.java-cn.com/user1/6749/archives/2005/18347.html
里面有很多例子代码，可以很方便上手。
POI的中级应该用
1、遍历workbook
代码
// load源文件
POIFSFileSystem fs = new POIFSFileSystem(new FileInputStream(filePath));
HSSFWorkbook wb = new HSSFWorkbook(fs);
for (int i = 0; i < wb.getNumberOfSheets(); i++) {
HSSFSheet sheet = wb.getSheetAt(i);
for (int i = sheet.getFirstRowNum(); i < sheet.getLastRowNum(); i ++) {
HSSFRow row = sheet.getRow(i);
if (row != null) {
。。。操作}
}
}
// 目标文件
FileOutputStream fos = new FileOutputStream(objectPath);
//写文件
swb.write(fos);
fos.close();
2、得到列和单元格
代码
HSSFRow row = sheet.getRow(i);
HSSFCell cell = row.getCell((short) j);
3、设置sheet名称和单元格内容为中文
代码
wb.setSheetName(n, "中文",HSSFCell.ENCODING_UTF_16);
cell.setEncoding((short) 1);
cell.setCellValue("中文");
4、单元格内容未公式或数值，可以这样读写
代码
cell.setCellType(HSSFCell.CELL_TYPE_NUMERIC);
cell.getNumericCellValue()
5、设置列宽、行高
代码
sheet.setColumnWidth((short)column,(short)width);
row.setHeight((short)height);
6、添加区域，合并单元格
代码
Region region = new Region((short)rowFrom,(short)columnFrom,(short)rowTo,(short)columnTo);
sheet.addMergedRegion(region);
//得到所有区域
sheet.getNumMergedRegions()
7、常用方法
根据单元格不同属性返回字符串数值
代码
public String getCellStringValue(HSSFCell cell) {
String cellValue = "";
switch (cell.getCellType()) {
case HSSFCell.CELL_TYPE_STRING:
cellValue = cell.getStringCellValue();
if(cellValue.trim().equals("")||cellValue.trim().length()<=0)
cellValue=" ";
break;
case HSSFCell.CELL_TYPE_NUMERIC:
cellValue = String.valueOf(cell.getNumericCellValue());
break;
case HSSFCell.CELL_TYPE_FORMULA:
cell.setCellType(HSSFCell.CELL_TYPE_NUMERIC);
cellValue = String.valueOf(cell.getNumericCellValue());
break;
case HSSFCell.CELL_TYPE_BLANK:
cellValue=" ";
break;
case HSSFCell.CELL_TYPE_BOOLEAN:
break;
case HSSFCell.CELL_TYPE_ERROR:
break;
default:
break;
}
return cellValue;
}
8、常用单元格边框格式
虚线HSSFCellStyle.BORDER_DOTTED
实线HSSFCellStyle.BORDER_THIN
代码
public static HSSFCellStyle getCellStyle(short type)
{
HSSFWorkbook wb = new HSSFWorkbook();
HSSFCellStyle style = wb.createCellStyle();
style.setBorderBottom(type);//下边框
style.setBorderLeft(type);//左边框
style.setBorderRight(type);//右边框
style.setBorderTop(type);//上边框
return style;
}
9、设置字体和内容位置
代码
HSSFFont f = wb.createFont();
f.setFontHeightInPoints((short) 11);//字号
f.setBoldweight(HSSFFont.BOLDWEIGHT_NORMAL);//加粗
style.setFont(f);
style.setAlignment(HSSFCellStyle.ALIGN_CENTER);//左右居中
style.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);//上下居中
style.setRotation(short rotation);//单元格内容的旋转的角度
HSSFDataFormat df = wb.createDataFormat();
style1.setDataFormat(df.getFormat("0.00%"));//设置单元格数据格式
cell.setCellFormula(string);//给单元格设公式
style.setRotation(short rotation);//单元格内容的旋转的角度
cell.setCellStyle(style);
10、插入图片
论坛里看到的
代码
//先把读进来的图片放到一个ByteArrayOutputStream中，以便产生ByteArray
ByteArrayOutputStream byteArrayOut = new ByteArrayOutputStream();
BufferedImage bufferImg = ImageIO.read(new File("ok.jpg"));
ImageIO.write(bufferImg,"jpg",byteArrayOut);
//读进一个excel模版
FileInputStream fos = new FileInputStream(filePathName+"/stencil.xlt");
fs = new POIFSFileSystem(fos);
//创建一个工作薄
HSSFWorkbook wb = new HSSFWorkbook(fs);
HSSFSheet sheet = wb.getSheetAt(0);
HSSFPatriarch patriarch = sheet.createDrawingPatriarch();
HSSFClientAnchor anchor = new HSSFClientAnchor(0,0,1023,255,(short) 0,0,(short)10,10);
patriarch.createPicture(anchor , wb.addPicture(byteArrayOut.toByteArray(),HSSFWorkbook.PICTURE_TYPE_JPEG));
11、设置列自动换行
HSSFCellStyle cellStyle = workbook.createCellStyle();
cellStyle.setWrapText(true);
sheet.setDefaultColumnStyle((short)0, cellStyle);
设置列的宽度
sheet.setColumnWidth((short)0,(short)9000);
sheet.setDefaultColumnStyle((short)0, cellStyle);
与
sheet.setDefaultColumnWidth((short)70);冲突
只会换行 不会设置列宽
单元格拷贝示例：
package testpoi;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.hssf.util.Region;
import org.apache.poi.poifs.filesystem.POIFSFileSystem;
/**
* 将某SHEET页中的某几行复制到某SHEET页的某几行中。抱括被合并了的单元格。
*/
public class RowCopy {
/**
* @param args
* @throws IOException
* @throws FileNotFoundException
*/
@SuppressWarnings("deprecation")
public static void main(String[] args) {
try {
POIFSFileSystem fs = new POIFSFileSystem(new FileInputStream(
"d://exlsample.xls"));
HSSFWorkbook wb = new HSSFWorkbook(fs);
// source为源sheet 页,target为目标sheet页
copyRows(wb, "source", "target", 5, 6, 20);
FileOutputStream fileOut = new FileOutputStream("d://exlsample.xls");
wb.write(fileOut);
fileOut.flush();
fileOut.close();
System.out.println("Operation finished");
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* @param wb HSSFWorkbook
* @param pSourceSheetName 源sheet页名称
* @param pTargetSheetName 目标sheet页名称
* @param pStartRow 源sheet页中的起始行
* @param pEndRow 源sheet页中的结束行
* @param pPosition 目标sheet页中的开始行
*/
public static void copyRows(HSSFWorkbook wb, String pSourceSheetName,
String pTargetSheetName, int intStartRow, int intEndRow, int intPosition) {
// EXECL中的行是从1开始的，而POI中是从0开始的，所以这里要减1.
int pStartRow = intStartRow - 1;
int pEndRow = intEndRow - 1;
int pPosition = intPosition - 1;
HSSFRow sourceRow = null;
HSSFRow targetRow = null;
HSSFCell sourceCell = null;
HSSFCell targetCell = null;
HSSFSheet sourceSheet = null;
HSSFSheet targetSheet = null;
Region region = null;
int cType;
int i;
int j;
int targetRowFrom;
int targetRowTo;
if ((pStartRow == -1) || (pEndRow == -1)) {
return;
}
sourceSheet = wb.getSheet(pSourceSheetName);
targetSheet = wb.getSheet(pTargetSheetName);
System.out.println(sourceSheet.getNumMergedRegions());
// 拷贝合并的单元格
for (i = 0; i < sourceSheet.getNumMergedRegions(); i++) {
region = sourceSheet.getMergedRegionAt(i);
if ((region.getRowFrom() >= pStartRow)
&& (region.getRowTo() <= pEndRow)) {
targetRowFrom = region.getRowFrom() - pStartRow + pPosition;
targetRowTo = region.getRowTo() - pStartRow + pPosition;
region.setRowFrom(targetRowFrom);
region.setRowTo(targetRowTo);
targetSheet.addMergedRegion(region);
}
}
// 设置列宽
for (i = pStartRow; i <= pEndRow; i++) {
sourceRow = sourceSheet.getRow(i);
if (sourceRow != null) {
for (j = sourceRow.getLastCellNum(); j > sourceRow
.getFirstCellNum(); j--) {
targetSheet
.setColumnWidth(j, sourceSheet.getColumnWidth(j));
targetSheet.setColumnHidden(j, false);
}
break;
}
}
// 拷贝行并填充数据
for (; i <= pEndRow; i++) {
sourceRow = sourceSheet.getRow(i);
if (sourceRow == null) {
continue;
}
targetRow = targetSheet.createRow(i - pStartRow + pPosition);
targetRow.setHeight(sourceRow.getHeight());
for (j = sourceRow.getFirstCellNum(); j < sourceRow
.getPhysicalNumberOfCells(); j++) {
sourceCell = sourceRow.getCell(j);
if (sourceCell == null) {
continue;
}
targetCell = targetRow.createCell(j);
targetCell.setCellStyle(sourceCell.getCellStyle());
cType = sourceCell.getCellType();
targetCell.setCellType(cType);
switch (cType) {
case HSSFCell.CELL_TYPE_BOOLEAN:
targetCell.setCellValue(sourceCell.getBooleanCellValue());
System.out.println("--------TYPE_BOOLEAN:"
+ targetCell.getBooleanCellValue());
break;
case HSSFCell.CELL_TYPE_ERROR:
targetCell
.setCellErrorValue(sourceCell.getErrorCellValue());
System.out.println("--------TYPE_ERROR:"
+ targetCell.getErrorCellValue());
break;
case HSSFCell.CELL_TYPE_FORMULA:
// parseFormula这个函数的用途在后面说明
targetCell.setCellFormula(parseFormula(sourceCell
.getCellFormula()));
System.out.println("--------TYPE_FORMULA:"
+ targetCell.getCellFormula());
break;
case HSSFCell.CELL_TYPE_NUMERIC:
targetCell.setCellValue(sourceCell.getNumericCellValue());
System.out.println("--------TYPE_NUMERIC:"
+ targetCell.getNumericCellValue());
break;
case HSSFCell.CELL_TYPE_STRING:
targetCell
.setCellValue(sourceCell.getRichStringCellValue());
System.out.println("--------TYPE_STRING:" + i
+ targetCell.getRichStringCellValue());
break;
}
}
}
}
/**
* POI对Excel公式的支持是相当好的，但是有一个问题，如果公式里面的函数不带参数，比如now()或today()，
* 那么你通过getCellFormula()取出来的值就是now(ATTR(semiVolatile))和today(ATTR(semiVolatile))，
* 这样的值写入Excel是会出错的，这也是我上面copyRow的函数在写入公式前要调用parseFormula的原因，
* parseFormula这个函数的功能很简单，就是把ATTR(semiVolatile)删掉。
* @param pPOIFormula
* @return
*/
private static String parseFormula(String pPOIFormula) {
final String cstReplaceString = "ATTR(semiVolatile)"; //$NON-NLS-1$
StringBuffer result = null;
int index;
result = new StringBuffer();
index = pPOIFormula.indexOf(cstReplaceString);
if (index >= 0) {
result.append(pPOIFormula.substring(0, index));
result.append(pPOIFormula.substring(index
+ cstReplaceString.length()));
} else {
result.append(pPOIFormula);
}
return result.toString();
}
}
public void exportToExcel() {
try {
ArrayList list = this.getSelectedCourseStudentsTableData();
System.out.println("=============size:" + list.size());
if (list != null && list.size() > 0) {
Long tp = new Long(System.currentTimeMillis());
String path = getApplicationBean().getFilePath()
+ "printfiles/" + tp.toString() + ".xls";
String name=path.substring(path.lastIndexOf('/')+1,path.length());
OutputStream outf = new FileOutputStream(path);
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("StudentCource");
sheet.setColumnWidth((short)0,(short)4000); //设置单元格的长度
sheet.setColumnWidth((short)3,(short)4000);
sheet.setColumnWidth((short)5,(short)6000);
sheet.setColumnWidth((short)6,(short)6000);
sheet.setHorizontallyCenter(true);
HSSFRow row1 = sheet.createRow(0);
HSSFCell cell1 = row1.createCell((short) 0);
cell1.setEncoding(HSSFCell.ENCODING_UTF_16);// 设置编码
cell1.setCellValue("学号");
cell1 = row1.createCell((short) 1);
cell1.setEncoding(HSSFCell.ENCODING_UTF_16);// 设置编码
cell1.setCellValue("姓名");
cell1 = row1.createCell((short) 2);
cell1.setEncoding(HSSFCell.ENCODING_UTF_16);// 设置编码
cell1.setCellValue("性别");
cell1 = row1.createCell((short) 3);
cell1.setEncoding(HSSFCell.ENCODING_UTF_16);// 设置编码
cell1.setCellValue("学生类别");
cell1 = row1.createCell((short) 4);
cell1.setEncoding(HSSFCell.ENCODING_UTF_16);// 设置编码
cell1.setCellValue("年级");
cell1 = row1.createCell((short) 5);
cell1.setEncoding(HSSFCell.ENCODING_UTF_16);// 设置编码
cell1.setCellValue("所属学院");
cell1 = row1.createCell((short) 6);
cell1.setEncoding(HSSFCell.ENCODING_UTF_16);// 设置编码
cell1.setCellValue("所学专业");
ArrayList selectedCourseStudentslist = this
.getSelectedCourseStudentsTableData();
for (int i = 0; i < selectedCourseStudentslist.size(); i++) {
HSSFRow row = sheet.createRow(i+1);
PgtStatusInfo pgtStatusInfo = (PgtStatusInfo) selectedCourseStudentslist
.get(i);
HSSFCell cell = row.createCell((short) 0);
cell.setCellValue(pgtStatusInfo.getStudentNo());
cell = row.createCell((short) 1);
cell.setEncoding(HSSFCell.ENCODING_UTF_16);
cell.setCellValue(pgtStatusInfo.getName());
cell = row.createCell((short) 2);
cell.setEncoding(HSSFCell.ENCODING_UTF_16);
cell.setCellValue(pgtStatusInfo.getSexCn());
cell = row.createCell((short) 3);
cell.setEncoding(HSSFCell.ENCODING_UTF_16);
cell.setCellValue(pgtStatusInfo.getPgtTypeCn());
cell = row.createCell((short) 4);
cell.setEncoding(HSSFCell.ENCODING_UTF_16);
cell.setCellValue(pgtStatusInfo.getGradeCn());
cell = row.createCell((short) 5);
cell.setEncoding(HSSFCell.ENCODING_UTF_16);
cell.setCellValue(pgtStatusInfo.getBelongDeptCn());
cell = row.createCell((short) 6);
cell.setEncoding(HSSFCell.ENCODING_UTF_16);
cell.setCellValue(pgtStatusInfo.getSpeCn());
}
wb.write(outf);
outf.close();
this.excelLink ="./files/printfiles/" + name;
this.excelFileLinkVisible = true;
this.outputFileLinkVisible = false;
} else {
getApplicationBean().addMessage(FacesMessage.SEVERITY_INFO,
"导出excel内容为空！", null);
}
} catch (Exception e) {
getApplicationBean().addMessage(FacesMessage.SEVERITY_ERROR,
"导出excel操作失败！", e.getMessage());
}
}