springSSM 使用poi导出excel(一)

var $form = $("<form>");   //定义一个form表单

$form.attr('style', 'display:none');   //在form表单中添加查询参数

$form.attr('target', '');

$form.attr('method', 'post');

$form.attr('action', actionurl);

$('body').append($form);  //将表单放置在web中

    $form.submit(); 

   byte[] fileNameByte = ("职业病基础知识.xls").getBytes("GBK");    
    String filename = new String(fileNameByte, "ISO8859-1"); 
    List<ZywsptGfxwjb> list = new ArrayList<ZywsptGfxwjb>();
    /*ZywsptGfxwjb zywsptGfxwjb = new ZywsptGfxwjb();
    zywsptGfxwjb.setMc("名称1");
    zywsptGfxwjb.setGjz("关键系");
    list.add(zywsptGfxwjb);*/
    list = gfxwjService.selectObjExist();
    byte[] bytes = excelService.export(list);
    response.setContentType("application/x-msdownload");    
    response.setContentLength(bytes.length);    
    response.setHeader("Content-Disposition", "attachment;filename="    
            + filename);    
    response.getOutputStream().write(bytes);
}

// 第一步，创建一个webbook，对应一个Excel文件    
    HSSFWorkbook wb = new HSSFWorkbook();

    // 第二步，在webbook中添加一个sheet,对应Excel文件中的sheet    
    HSSFSheet sheet = wb.createSheet(sheet1); 

    // 第三步，在sheet中添加表头第0行,注意老版本poi对Excel的行数列数有限制short  

    HSSFRow row = sheet.createRow((int) 0);

    // 第四步，创建单元格，并设置值表头 设置表头居中    
    HSSFCellStyle style = wb.createCellStyle();

    style.setAlignment(HSSFCellStyle.ALIGN_CENTER); // 创建一个居中格式

    //设置表头    
    List<ExportFiledsBean> excelHead = getExcelHead(clazz);
    String clazzName = clazz.getName();
    Class  _class = Class.forName(clazzName);
    
    HSSFCell cell = null;
    // excel头    
    for (int i = 0; i < excelHead.size(); i++) {   
    	ExportFiledsBean exportFiledsBean = excelHead.get(i);
        cell = row.createCell(i);    
        cell.setCellValue(exportFiledsBean.getName());    
        cell.setCellStyle(style);
    }  
    
    for (int i = 0;i<list.size();i++)
    {
    	row = sheet.createRow((int) i + 1); 
    	Object obj = (Object) list.get(i);
    	for(int j=0;j<excelHead.size();j++)
    	{
    		ExportFiledsBean exportFiledsBean = excelHead.get(j);
    		String getFuncName = exportFiledsBean.getGetFuncName();
    		
    		Method addMethod = _class.getMethod(getFuncName);
    		Object result = addMethod.invoke(obj);
    		if(result==null)
    		{
    			row.createCell((int) j).setCellValue("");
    		}else{
    			row.createCell((int) j).setCellValue(result.toString());
    		}
    	}
    	
    }
    wb.write(out); 
    // 第五步，写入实体数据 实际应用中这些数据从数据库得到
	return out.toByteArray();
}

private static List<ExportFiledsBean> getExcelHead(Class<?> clazz){

	return AunotationUtil.getExportFileds(clazz);

}

private void insertCell(HSSFRow row,int i,Object object){    

    if(object==null){    

        row.createCell(i).setCellValue("");    
            
    }else{    

        row.createCell(i).setCellValue(object.toString());    
            
    }    
        
}

/**
 * 获取注解的方法
 * [@param](https://my.oschina.net/u/2303379) clazz
 * [@return](https://my.oschina.net/u/556800)
 */
public static List<ExportFiledsBean> getExportFileds(Class<?> clazz){

	List<ExportFiledsBean> exportFiledsBeans = new ArrayList<ExportFiledsBean>();

	String clazzName = clazz.getName();

	//System.out.println("class的name："+clazzName);

	Field[] fileds = clazz.getDeclaredFields();
	for(Field field :fileds)
	{
		if(field.isAnnotationPresent(ExportField.class))
		{
			ExportField exportField=(ExportField)field.getAnnotation(ExportField.class);
			String fieldName = field.getName();
			String name = exportField.name();
			String setFuncName = exportField.setFuncName();
			String getFuncName = exportField.getFuncName();
			boolean bl = exportField.isExport();
			
			ExportFiledsBean exportFiledsBean = new ExportFiledsBean();
			if(bl==true)
			{
				exportFiledsBean.setFiledName(fieldName);
				exportFiledsBean.setName(name);
				exportFiledsBean.setSetFuncName(setFuncName);
				exportFiledsBean.setGetFuncName(getFuncName);
				//System.out.println(fieldName+":"+name+":"+setFuncName+":"+getFuncName);
				exportFiledsBeans.add(exportFiledsBean);
			}
		}
	}
	
	return exportFiledsBeans;
}

public static void main(String[] arg)
{
	AunotationUtil.getExportFileds(ZywsptGfxwjb.class);
}

public String name() default "filedName";
public String setFuncName() default "setField";
    public String getFuncName() default "getField";
    public boolean isExport() default false;

private String filedName;

private String name;

private String setFuncName;

private String getFuncName;

@ExportField(name="编码",setFuncName="setId",getFuncName="getId",isExport=false)
private BigDecimal id;

@ExportField(name="名称",setFuncName="setMc",getFuncName="getMc",isExport=true)
private String mc;

@ExportField(name="关键字",setFuncName="setGjz",getFuncName="getGjz",isExport=true)
private String gjz;