导出文件

所需jar包：poi-3.8-20120326.jar

package excl;

import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;

import javax.servlet.http.HttpServletResponse;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFFont;
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.struts2.ServletActionContext;

public class TestExcl {
	
	public static void exportExcel() throws IOException{
	//声明一个工作簿
	HSSFWorkbook workbook= new HSSFWorkbook();
	//生成一个表格
	HSSFSheet sheet = workbook.createSheet("我的表格");
	//设置表格的默认宽度为20个字节
	sheet.setDefaultColumnWidth(20);
	
	//生成一个样式
	HSSFCellStyle style = workbook.createCellStyle();
	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);
    
    //把字体应用到当前样式
    style.setFont(font);
    
    //指定当前单元格内容显示不下时自动换行
    style.setWrapText(true);
    
    /* 
    
    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");
   
   */  
     
     //设置标题行
    HSSFRow row = sheet.createRow(0);
    List<String> list = new ArrayList<String>();
    list.add("姓名");
    list.add("性别");
    list.add("年龄");
    list.add("身高");
    for(int i=0;i<list.size();i++){
    	HSSFCell cell=row.createCell(i);
    	cell.setCellStyle(style);
    	HSSFRichTextString text = new HSSFRichTextString(list.get(i));
    	cell.setCellValue(text);
    }
    //遍历集合数据，产生数据行
    List<LinkedHashMap<String,Object>> lists = 
    	new ArrayList<LinkedHashMap<String,Object>>();
    LinkedHashMap<String,Object> l=new LinkedHashMap<String,Object>();
    l.put("xm", "zhangsan");
    l.put("xb", "nv");
    l.put("nl", "25");
    l.put("sg", "165");
    lists.add(l);
    
    String[] columns = {"xm","xb","nl","sg"};
    int index=1;
    for(LinkedHashMap<String,Object> link:lists){
    	row = sheet.createRow(index);
    	int cellIndex=0;
    	for(String s:columns){
    		HSSFCell cell = row.createCell(cellIndex);
    		HSSFRichTextString text = 
    			new HSSFRichTextString(link.get(s)==null?"":link.get(s).toString());
    		cell.setCellValue(text);
    		cellIndex++;
    	}
    	index++;
    }
    HttpServletResponse response = ServletActionContext.getResponse();
    OutputStream out = response.getOutputStream();
    workbook.write(out);
	}
	
	
	public String onHead(){  
        try {  
            HttpServletResponse response = ServletActionContext.getResponse();  
            response.setContentType("octets/stream");  
            response.addHeader("Content-Disposition","attachment;filename=test.xls");  
            OutputStream out = response.getOutputStream();  
            exportExcel();  
            out.close();  
        } catch (Exception e) {  
        }  
        return null;  
    }  
	
}

response的用法：

HttpServletResponse response = ServletActionContext.getResponse(); 
            response.setContentType("octets/stream"); 
            response.addHeader("Content-Disposition","attachment;filename=test.xls"); 
            OutputStream out = response.getOutputStream(); 
            exportExcel(); 
            out.close();