将图片以Blob格式存入数据库,再通过Servlet显示到界面

1:为了方便测试,直接将1.png图片存入到数据库中.

public static void storePicBlog() throws FileNotFoundException, SQLException, IOException{
        Connection conn = JdbcUtil.getConnection();
        File f = new File("1.jpg");
        FileInputStream fis = new FileInputStream(f);

        String sql = "insert into pic_test(id,zp) values(?,?)";

        PreparedStatement ps = conn.prepareStatement(sql);

        ps.setString(1, StringUtil.getUUID());
        ps.setBinaryStream(2, fis, (int)f.length());

        ps.executeUpdate();

        fis.close();
        ps.close();
        JdbcUtil.release(conn);
    }

2:进行读取操作

public static InputStream getPicInputStream(){
        String id = "f304733361e243779b2340afe20e62bf";

         Connection conn = JdbcUtil.getConnection();

         PreparedStatement ps = null;

         ResultSet rs = null;

         InputStream is = null;

         String sql = "select zp from pic_test where id= ?";

        try {

            ps = conn.prepareStatement(sql);

            ps.setString(1, id);

            rs = ps.executeQuery();

            if(rs.next()){
                is = rs.getBlob("zp").getBinaryStream();
            }

        } catch (SQLException ex) {
            Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
        }finally{
            try {
                if(null!=ps){
                    ps.close();
                }
            } catch (SQLException ex) {
                Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
            }
            try {
                if(null!=rs){
                    rs.close();
                }
            } catch (SQLException ex) {
                Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
            }
            JdbcUtil.release(conn);
        }

        return is;
    }

3:测试Servlet,通过浏览器访问此Servlet,一定要设置:

response.setContentType("image/jpeg");浏览器中才可以将图片显示出来

protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("image/jpeg");

        InputStream is = Test.getPicInputStream();

        if(null!=is){

            OutputStream os = response.getOutputStream();

            int len;

            byte buf[] = new byte[1024];

            while((len=is.read(buf))!=-1){
                os.write(buf, 0, len);
            }

            is.close();
            os.close();
        }

    }