poi 导出Excel 工具类详解编程语言

import java.io.OutputStream; 
import java.lang.reflect.Method; 
import java.text.SimpleDateFormat; 
import java.util.Collection; 
import java.util.Date; 
import java.util.regex.Matcher; 
import java.util.regex.Pattern; 
import org.apache.poi.hssf.usermodel.HSSFCell; 
import org.apache.poi.hssf.usermodel.HSSFCellStyle; 
import org.apache.poi.hssf.usermodel.HSSFClientAnchor; 
import org.apache.poi.hssf.usermodel.HSSFFont; 
import org.apache.poi.hssf.usermodel.HSSFPatriarch; 
import org.apache.poi.hssf.usermodel.HSSFRichTextString; 
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.HSSFColor; 
import org.apache.poi.hssf.util.Region; 
/** 
* 
* @author Bruce Xu 
* 
* @param <T> 
*/ 
public class ExcelUtil<T> {    
/**  
* 导出Excel的方法  
* @param title excel中的sheet名称  
* @param headers 表头  
* @param result 结果集  
* @param out 输出流  
* @param pattern 时间格式  
* @throws Exception  
*/    
public void exportExcel(String title, String[] headers,String[] columns, Collection<T> result, OutputStream out, String pattern) throws Exception{    
// 声明一个工作薄    
HSSFWorkbook workbook = new HSSFWorkbook();    
// 生成一个表格    
HSSFSheet sheet = workbook.createSheet(title);    
// 设置表格默认列宽度为20个字节    
sheet.setDefaultColumnWidth((short)20);    
// 生成一个样式    
HSSFCellStyle style = workbook.createCellStyle();    
// 设置这些样式    
style.setFillForegroundColor(HSSFColor.GOLD.index);    
style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);    
style.setBorderBottom(HSSFCellStyle.BORDER_THIN);    
style.setBorderLeft(HSSFCellStyle.BORDER_THIN);    
style.setBorderRight(HSSFCellStyle.BORDER_THIN);    
style.setBorderTop(HSSFCellStyle.BORDER_THIN);    
style.setAlignment(HSSFCellStyle.ALIGN_CENTER);    
// 生成一个字体    
HSSFFont font = workbook.createFont();    
font.setColor(HSSFColor.VIOLET.index);    
//font.setFontHeightInPoints((short) 12);    
font.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);    
// 把字体应用到当前的样式    
style.setFont(font);    
// 指定当单元格内容显示不下时自动换行    
style.setWrapText(true);    
// 声明一个画图的顶级管理器   
HSSFPatriarch patriarch = sheet.createDrawingPatriarch();  
/*  
以下可以用于设置导出的数据的样式  
// 生成并设置另一个样式  
HSSFCellStyle style2 = workbook.createCellStyle();  
style2.setFillForegroundColor(HSSFColor.LIGHT_YELLOW.index);  
style2.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);  
style2.setBorderBottom(HSSFCellStyle.BORDER_THIN);  
style2.setBorderLeft(HSSFCellStyle.BORDER_THIN);  
style2.setBorderRight(HSSFCellStyle.BORDER_THIN);  
style2.setBorderTop(HSSFCellStyle.BORDER_THIN);  
style2.setAlignment(HSSFCellStyle.ALIGN_CENTER);  
style2.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);  
// 生成另一个字体  
HSSFFont font2 = workbook.createFont();  
font2.setBoldweight(HSSFFont.BOLDWEIGHT_NORMAL);  
// 把字体应用到当前的样式  
style2.setFont(font2);  
// 声明一个画图的顶级管理器  
HSSFPatriarch patriarch = sheet.createDrawingPatriarch();  
// 定义注释的大小和位置,详见文档  
HSSFComment comment = patriarch.createComment(new HSSFClientAnchor(0, 0, 0, 0, (short) 4, 2, (short) 6, 5));  
// 设置注释内容  
comment.setString(new HSSFRichTextString("可以在POI中添加注释！"));  
// 设置注释作者，当鼠标移动到单元格上是可以在状态栏中看到该内容.  
comment.setAuthor("leno");*/    
// 产生表格标题行    
//表头的样式  
HSSFCellStyle titleStyle = workbook.createCellStyle();// 创建样式对象  
titleStyle.setAlignment(HSSFCellStyle.ALIGN_CENTER_SELECTION);// 水平居中  
titleStyle.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);// 垂直居中  
// 设置字体  
HSSFFont titleFont = workbook.createFont(); // 创建字体对象  
titleFont.setFontHeightInPoints((short) 15); // 设置字体大小  
titleFont.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);// 设置粗体  
//  titleFont.setFontName("黑体"); // 设置为黑体字  
titleStyle.setFont(titleFont);  
sheet.addMergedRegion(new Region(0,(short)0,0,(short)(headers.length-1)));//指定合并区域   
HSSFRow rowHeader = sheet.createRow(0);    
HSSFCell cellHeader = rowHeader.createCell((short)0);   //只能往第一格子写数据，然后应用样式，就可以水平垂直居中  
HSSFRichTextString textHeader = new HSSFRichTextString(title);    
cellHeader.setCellStyle(titleStyle);  
cellHeader.setCellValue(textHeader);  
HSSFRow row = sheet.createRow(1);    
for (int i = 0; i < headers.length; i++) {    
HSSFCell cell = row.createCell((short)i);    
cell.setCellStyle(style);    
HSSFRichTextString text = new HSSFRichTextString(headers[i]);    
cell.setCellValue(text);    
}    
// 遍历集合数据，产生数据行    
if(result != null){    
int index = 2;    
for(T t:result){   
//  Field[] fields = t.getClass().getDeclaredFields();  
row = sheet.createRow(index);    
index++;  
for(short i = 0; i < columns.length; i++) {  
HSSFCell cell = row.createCell(i);  
//                   Field field = fields[i];  
//                   String fieldName = field.getName();  
String fieldName = columns[i];  
String getMethodName = "get"  
+ fieldName.substring(0, 1).toUpperCase() + fieldName.substring(1);  
Class tCls = t.getClass();  
Method getMethod = tCls.getMethod(getMethodName, new Class[]{});  
// getMethod.getReturnType().isInstance(obj); 
Object value = getMethod.invoke(t, new Class[]{});  
String textValue = null;  
if(value == null) {  
textValue = "";  
}else if (value instanceof Date) {  
Date date = (Date) value;  
SimpleDateFormat sdf = new SimpleDateFormat(pattern);  
textValue = sdf.format(date);  
}  else if (value instanceof byte[]) {  
// 有图片时，设置行高为60px;  
row.setHeightInPoints(60);  
// 设置图片所在列宽度为80px,注意这里单位的一个换算  
sheet.setColumnWidth(i, (short) (35.7 * 80));  
// sheet.autoSizeColumn(i);  
byte[] bsValue = (byte[]) value;  
HSSFClientAnchor anchor = new HSSFClientAnchor(0, 0,  
1023, 255, (short) 6, index, (short) 6, index);  
anchor.setAnchorType(2);  
patriarch.createPicture(anchor, workbook.addPicture(  
bsValue, HSSFWorkbook.PICTURE_TYPE_JPEG));  
} else{  
//其它数据类型都当作字符串简单处理  
textValue = value.toString();  
}  
if(textValue!= null){  
Pattern p = Pattern.compile("^//d+(//.//d+)?$");    
Matcher matcher = p.matcher(textValue);  
if(matcher.matches()){  
//是数字当作double处理  
cell.setCellValue(Double.parseDouble(textValue));  
}else{  
HSSFRichTextString richString = new HSSFRichTextString(textValue);  
//                            HSSFFont font3 = workbook.createFont();  
//                            font3.setColor(HSSFColor.BLUE.index);  
//                            richString.applyFont(font3);  
cell.setCellValue(richString);  
}  
}  
}  
}       
}    
workbook.write(out);    
}    
}   

调用示例：以springmvc为例，导出数据库记录到Excel,弹出下载对话框

@RequestMapping(value="/exprotExcel") 
public @ResponseBody String exprotExcel(HttpServletResponse response,NjWorkLog njWorkLog,@RequestParam(value="createUserIds",required=false) String createUserIds,@RequestParam(value="workLogGrantUsersName",required=false)String workLogGrantUsersName,@RequestParam(value="strWorkEndDate",required=false)String strWorkEndDate) 
{ 
ExcelUtil<NjWorkLog> excelUtil=new ExcelUtil<NjWorkLog>(); 
OutputStream out=null; 
try 
{ 
out = response.getOutputStream();// 取得输出流   
//out.flush(); 
response.reset();// 清空输出流   
response.setHeader("Content-disposition", "attachment; filename="+new String("工作日志".getBytes("GB2312"),"8859_1")+".xls");// 设定输出文件头   
response.setContentType("application/msexcel");// 定义输出类型 
}  catch (IOException e) 
{ 
e.printStackTrace(); 
}  
String[] headers ={"跟踪目标","工作时间","事项类型","项目名称","完成情况自述","工作量","进度","配合人员","加班","作者","附件名称"}; 
String[]columns={ "strTarget", "strWorkDate", "dictTypeId", "projectId", "strDesc", "bdWorkload", "strSchedule", "strCooperate","isOverTime","createUserId", "strFileName"}; 
if("on".equals(njWorkLog.getIsOverTime())) 
njWorkLog.setIsOverTime("1"); 
else 
njWorkLog.setIsOverTime(""); 
if(StringUtils.isNotBlank(createUserIds)) 
njWorkLog.setTempArray(createUserIds.split(",")); 
List<NjWorkLog> dataset=njWorkLogService.findMyAttentionExcel(njWorkLog); 
try 
{ 
excelUtil.exportExcel("工作日志", headers, columns, dataset, out, ""); 
} catch (Exception e1) 
{ 
e1.printStackTrace(); 
} 
try 
{ 
out.close(); 
} catch (IOException e) 
{ 
e.printStackTrace(); 
} 
return null; 
}