记录下来，方便以后再用~·
servlet中图片存入：

public void SaveDeliveryReceipt(HttpServletRequest req,HttpServletResponse resp)throws ServletException, IOException {

		String strAdmin = (String) req.getSession().getAttribute("isAdmin");
		boolean isAdmin = "1".equals(strAdmin);
		Long op_id = Long.parseLong(req.getParameter("op_id"));
		String opt_type =  objectToString(req.getParameter("op_type"));
		Date opt_time = DateBuilder.strToUtilDateWithFormat(objectToString(req.getParameter("op_time")));
		String op_cert_dn =  URLDecoder.decode(objectToString(req.getParameter("op_certdn")), "utf-8");
		String signLog =  objectToString(req.getParameter("sign_data"));

		JSONObject json = new JSONObject();
		json.put("success", false);
		
		try {
			
			DiskFileUpload fu = new DiskFileUpload(); 
			// 设置允许用户上传文件大小,单位:字节 
			fu.setHeaderEncoding("UTF-8");
			fu.setSizeMax(1000000000);

			List fileItems = fu.parseRequest(req);
			FileItem item = (FileItem) fileItems.get(0); // 只有一个文件
			InputStream inStream = item.getInputStream();
			
			ByteArrayOutputStream bytestream = new ByteArrayOutputStream();
			int ch;
			while ((ch = inStream.read()) != -1) {
				bytestream.write(ch);
			}
			byte imgdata[] = bytestream.toByteArray();
			bytestream.close();
			//统一图片大小
			this.ChangeImgSize(imgdata,300,300);
			
			String send_number = objectToString(req.getParameter("send_number"));
			CertSend certSend= new CertSend();
			certSend.setSend_number(send_number);
			CertSend objcertSend = certSendService.selectCert(certSend);
			this.writeByteArryToImage(imgdata, send_number);
			objcertSend.setReceive_evidence(imgdata);
			inStream.close();
			certSendService.updateCertSend(objcertSend);
			String strErrMsg = "用户签收凭据导入成功！";
			errMsg.setErrMsg(strErrMsg);
			json.put("err", errMsg);
			json.put("success", true);
			if(!isAdmin){
				opLog.writeOptLog(strErrMsg,op_id,null,op_cert_dn, opt_type,opt_time,"SUCCESS",signLog,null,null,null,null,null,null);
			}
		}
		catch (Exception e) {
			String strErrMsg = " 检测需要导入凭据是否已存在异常！";
			errMsg.setErrMsg(strErrMsg);
			json.put("err", errMsg.toJson());
			if(!isAdmin){
				sysLog.writeSysLog(strErrMsg,"FAILURE","SysCertImportServlet",e.getMessage());
				opLog.writeOptLog(strErrMsg,op_id, null,op_cert_dn, opt_type,opt_time, "FAILURE", signLog,null,null,null,null,null,null); 
			}
			showErrMsg(json,strErrMsg,"SysCertImportServlet",e);
		}
		finally{
			try {
				resp.setContentType("text/html;charset=UTF-8");  
			    resp.getWriter().write(json.toString());
			}
			catch (Exception e2) {
			}
		}
	
		
	}
将blog类型取出：
public void GetImageByteId(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException{

		String strId=req.getParameter("id");
		CertSend temp=new CertSend();
		temp.setSend_number(strId);
		CertSend query=certSendService.selectCert(temp);
		byte[] data=null;
		data= query.getReceive_evidence();
		try{
			//清除页面缓存
			resp.setHeader("Pragma", "No-cache");
			resp.setHeader("Cahe-Control", "no-cache");
			resp.setDateHeader("Expires", 0);
				InputStream inStream=new ByteArrayInputStream(data);
				int size=-1;
				size=inStream.read(data, 0, data.length);
				ServletOutputStream sout= resp.getOutputStream();
				if(size>0){
					sout.write(data,0,size);
				}
				inStream.close();
			
			//data=ChangeImgSize(data,w,h);
		}catch(Exception ex){
			ex.printStackTrace();
		}
	
		
		
	} 
前台ext页面显示：
{
				xtype : "component",
				width:200,
				height:300,
				autoHeight:true,
				id:"browseImage",
				name:"browseImage",
				autoEl:{
				tag:'img',
				src:'certSend.fm?method=GetImageByteId&id='+check+''
			}
			}