blob存取数据库

将图片以blob存入数据库

public String uploadfile() {
        try {
            HttpServletResponse response = ServletActionContext.getResponse();
            HttpServletRequest request = ServletActionContext.getRequest();
            String path = request.getContextPath();
            Blob photo = null;
            String basePath = request.getScheme() + "://"+ request.getServerName() + path + "/";
            String filename = getNum();
            //判断是否为图片
            if(isImage(myFile)){ // File类型

            }else{
               return ERROR;
            }
            filename += ".png";
            Photolist pl = new Photolist();
            FileInputStream fis = new FileInputStream(myFile);
            photo = Hibernate.createBlob(fis);   // org.hibernate.Hibernate

            pl.setImagefile(photo);
            pl.setAddtime(new Date());
            pl.setName(filename);
            service.save(pl);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

public boolean isImage(File imageFile) {
        if (!imageFile.exists()) {
            return false;
        }
        Image img = null; // java.awt.Image

try {
img = ImageIO.read(imageFile); // javax.imageio.ImageIO

            if (img == null || img.getWidth(null) <= 0 || img.getHeight(null) <= 0) {
                return false;
            }
            return true;
        } catch (Exception e) {
            return false;
        } finally {
            img = null;
        }
    }

从数据库中读出blob

public String getImageFile() {
        try {
            HttpServletResponse response = ServletActionContext.getResponse();
            HttpServletRequest request = ServletActionContext.getRequest();
            String pid = request.getParameter("pid");
            ServletOutputStream out = ServletActionContext.getResponse().getOutputStream();
            Photolist pl = new Photolist();
            pl = (Photolist) service.get(Photolist.class, Long.parseLong(pid));
            int len = 0;
            Blob blob = pl.getImagefile(); //该字段类型为Blob
            InputStream input = blob.getBinaryStream();
            byte[] image = new byte[(int) blob.length()];
            while ((len = input.read(image)) != -1) {
                out.write(image, 0, len);
            }
            out.flush();
            out.close();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return null;
    }

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