Java poi导出excel封装的工具类

废话不多说，直接上代码了，还是补一句，就是：数据放到实体类里边，然后放到map集合中，再把map放到List集合中，最后调用工具类，即可导出。

1. maven依赖

		
		    org.apache.poi
		    poi
		    3.16
		
		
		    org.apache.poi
		    poi-ooxml
		    3.16
            
                
                    xmlbeans
                    org.apache.xmlbeans
                
            
        

注意：如果使用的是springboot记得exclusions掉xmlbeans，因为可能会有冲突

2. excel导出工具类

package //TODO

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import java.util.Map;
import java.util.Set;

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.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;

public class ExcelUtils {

	private static final int PAGE_NUM = 65500;
		/**
		 * 非空判断
		 * @param obj
		 * @return
		 */
	 public static boolean isEmptyOrNull(Object obj){
	    	if(obj == null){
	    		return true;
	    	}
	    	if(obj instanceof Map){
	    		return ((Map) obj).isEmpty();
	    	}else if(obj instanceof List){
	    		return ((List) obj).isEmpty();
	    	}
	    	return obj.toString().isEmpty();
	  }
	
	
	/**
	 * 获取工作簿
	 * @param list
	 * @param columnMap
	 * @return
	 * @throws Exception
	 */
	public static HSSFWorkbook getHSSFWorkbook(List> list, Map columnMap){
		
		HSSFWorkbook wb = new HSSFWorkbook();
		//对集合进行非空判断
		if(isEmptyOrNull(list) || isEmptyOrNull(columnMap)){
			wb.createSheet();
			return wb;
		}
		
		int pageNum = PAGE_NUM;//每页数量
		int size = list.size();//数据数量
		int pages = (size % pageNum > 0) ? (size / pageNum + 1) : (size / pageNum);//导出页数
		
		HSSFCellStyle cs = null;//单元格样式
		HSSFSheet sheet = null;//页面
		HSSFFont font = wb.createFont();//字体
		
		font.setFontHeightInPoints((short) 11);//设置字号 
		cs = wb.createCellStyle();
		
		cs.setFont(font);
		cs.setFillPattern(HSSFCellStyle.FINE_DOTS);
		
		Set keySet = columnMap.keySet();
		HSSFRow row = null;//单元格行
		Object columnvalue = null;
		String columnTitle = null;
		Map dataMap = null;
		
		for (int i = 0; i < pages; i++) {
			sheet = wb.createSheet();
			wb.setSheetName(i, (String.valueOf((i + 1))));
			row = sheet.createRow(0);
			for(String keyColumn : keySet){
				columnTitle = columnMap.get(keyColumn);
				createStringCell(row, (short) row.getLastCellNum() == -1 ? 0 : (short) row.getLastCellNum(), columnTitle, cs);
			}
			for(int j = 0; j < size; j++){
				dataMap = list.get(j);
				row = sheet.createRow(j + 1 - (pageNum * i));
				for(String keyColumn : keySet){
					columnvalue = dataMap.get(keyColumn);
					createStringCell(row, (short) row.getLastCellNum() == -1 ? 0 : (short) row.getLastCellNum(), columnvalue, cs);
				}
			}
		}
		return wb;
		
		
	}
	
	/**
	 * 创建单元格
	 * @param row
	 * @param index
	 * @param value
	 * @param cs
	 */
	private static void createStringCell(HSSFRow row, short index, Object value, HSSFCellStyle cs) {
		HSSFCell cell = row.createCell(index);
		cell.setCellType(HSSFCell.CELL_TYPE_STRING);
		cs.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);
		cs.setAlignment(HSSFCellStyle.ALIGN_CENTER);
		if(!isEmptyOrNull(value) && value instanceof Date){
			value = doDate2String((Date)value);
		}
		cell.setCellValue(null2Empty(value));
	}
	
	
	/**
	 * 将日期转化为String
	 * @param confirmDate
	 * @param patten
	 * @return
	 */
	public static String doDate2String(Date confirmDate, String... patten) {
		if(confirmDate == null){
			return "";
		}
		SimpleDateFormat sdf = null;
		if(patten == null || patten.length == 0){
			sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
		}else{
			sdf = new SimpleDateFormat(patten[0]);
		}
		return sdf.format(new Date(confirmDate.getTime()));
	}
	
	/**
	 * 将null转化为Empty
	 * @param areaId
	 * @return
	 */
	public static String null2Empty(Object areaId) {
		return areaId == null ? "" : areaId.toString();
	}
}

注意：关键方法：getHSSFWorkbook

3. controller方法：

	@RequestMapping(value="download")
	public void downloadExcel(HttpServletRequest request,HttpServletResponse response,IsEntity isEntity){
	
		StringBuffer sbBuffer = new StringBuffer();
		sbBuffer.append("这是文件名");
		sbBuffer.append(CommonUtil.dateToString(new Date()));
		sbBuffer.append(".xls");
		String fileName =  sbBuffer.toString();
		
	    //excel 写入数据 service层 TODO 这个自己注入进来
	    HSSFWorkbook wb = this.offlineService.downloadExcel(isEntity);
	    
	    this.setResponseHeader(response, fileName);
	    try {
            OutputStream os = response.getOutputStream();
	        wb.write(os);
	        os.flush();
	        os.close();
		} catch (IOException e) {
			//TODO 处理异常
		}
	}


    //发送响应流方法
    private void setResponseHeader(HttpServletResponse response, String fileName) {
        try {
            try {
                fileName = new String(fileName.getBytes(),"ISO8859-1");
            } catch (UnsupportedEncodingException e) {
                //TODO 处理异常
            }
            response.setContentType("application/octet-stream;charset=ISO8859-1");
            response.setHeader("Content-Disposition", "attachment;filename="+ fileName);
            response.addHeader("Pargam", "no-cache");
            response.addHeader("Cache-Control", "no-cache");
        } catch (Exception ex) {
            //TODO 处理异常
        }
    }

3. 调用service的方法

	/**
	 * 导出excel
	 * @param offlineQueryEntity
	 */
	public HSSFWorkbook downloadExcel(IsEntity isEntity) {
		try {
            //查询数据
		    List query = this.query(IsEntity );
			//标题
			Map column = new TreeMap();
			column.put("A1","excel标题");
			column.put("A2","excel标题");
			column.put("A3","excel标题");
		    
			//excel内容
		    List> listResult = new ArrayList>();
		    if(query!=null && !query.isEmpty()){
		    	
		    	for (IsEntity vo: query) {
		    		Map hashMap = new HashMap();
		    		hashMap.put("A1",vo.getId());
		    		hashMap.put("A2",vo.getName());
		    		hashMap.put("A3",vo.getPassWord());
		    		
		    		listResult.add(hashMap);
		    	}
		    }
			
            //去调用工具类的方法
			HSSFWorkbook wb = ExcelUtils.getHSSFWorkbook(listResult, column);
			return wb;
		} catch (Exception e) {
			//TODO处理异常
		}
		return null;
	}

注意：标题是指导出excel的标题，标题名称自己修改，excel的内容即是查询出来的数据，放到实体类IsEntity中。

4. 实体类IsEntity

package //TODO 包名

public class IsEntity {

	private String id;
	private String name;
	private String passWord;
	public String getId() {
		return id;
	}
	public void setId(String id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getPassWord() {
		return passWord;
	}
	public void setPassWord(String passWord) {
		this.passWord = passWord;
	}
	
	
}