1,数据库的字段用BLOB接受  hibernate映射blob

2,存储二维码

     public static Blob StorageTwoDimensionCode(TbAssets assets) throws IOException{
        
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();//字节数组流
        code.encoderQRCode(content, outputStream, "png",9);
        
        //这里的Blob是java.sql包中的
        Blob codeimg =  Hibernate.createBlob(outputStream.toByteArray()); //outputStream转一个blob，这里可以接收InputStream和byte[]
        outputStream.flush();
        outputStream.close();
        
        return codeimg; //返回一个blob
    }

3，如果要读出来，在页面显示

public void showCodeImg(){
        TbAssets assets = assetsService.getAssetsById(asid);
        Blob codeimg = assets.getCodeImg();
        try {
            BufferedInputStream inputStream = new BufferedInputStream(codeimg.getBinaryStream()); //把BLOB数据转为二进制流
            BufferedOutputStream outputStream = new BufferedOutputStream(ServletActionContext.getResponse().getOutputStream());
            byte[] b = new byte[1024];
            int len = 0 ;
            while ((len=inputStream.read(b))!=-1) {
                outputStream.write(b, 0, len);
            }
            outputStream.flush();
            inputStream.close();
            outputStream.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }