数据库存储图片 Blod格式2（下载）

Posted on 2018-03-19 12:28  弯弓射雕的男人  阅读(913)  评论(0)  编辑  收藏  举报

此文接上篇 主要想讲一下图片的下载 

框架背景 ：spring + hibernate 

看代码  ok 走你

 1 public void getDate(HttpServletRequest request, HttpServletResponse response,String id) throws Exception {
 2         Connection conn = null;
 3         PreparedStatement ps =null;
 4         ResultSet rs = null;
 5         response.reset();
 6         //response.setContentType("image/*;charset=GBK");
 7         //response.setContentType("image/jpeg");
 8         //response.setContentType("text/html; charset=GBK");
 9         response.setContentType("unknown"); 
10         
11         try{
12             conn = DataSourceUtils.getConnection(jdbcTemplate.getDataSource());
13             String sql = "select img，msg，filename from "+tableName+" where id = " +"'"+id+"'";
14             System.out.println(sql);
15             ps = conn.prepareStatement(sql);
16             rs = ps.executeQuery();
17             if(rs.next()){
18                 Blob blob = rs.getBlob("img");
19                 String name=rs.getString("filename");
20                 response.addHeader("content-disposition", "attachment;filename=\"" + name+"\"");
21                 //response.setContentType("application/x-download"); 
22                 //response.setContentType("application/x-msdownload");
23                 //response.addHeader("Content－Disposition","attachment;filename="+clmc+"."+cllx);
24                 InputStream pi = blob.getBinaryStream();
25                 OutputStream sos = response.getOutputStream();
26                 byte bytes[] = new byte[(int)((BLOB)blob).length()];
27                 for(int n = 0; (n = pi.read(bytes)) != -1;)sos.write(bytes, 0, n);
28                 pi.close();
29                 sos.flush();
30             }
31         }catch(Exception ex){
32             DataSourceUtils.releaseConnection(conn, jdbcTemplate.getDataSource());
33             throw new Exception("执行时出错!" + ex.getMessage());
34         }finally{
35             if(rs!=null)rs.close();
36             if(ps!=null)ps.close();
37             if(conn!=null){
38                 try{
39                     DataSourceUtils.releaseConnection(conn,jdbcTemplate.getDataSource());
40                 }catch(Exception ex){
41                     ex.printStackTrace();
42                 }
43             }
44         }
45     }

看完之后你会发现 其实很简单

就是 用

 response.addHeader("content-disposition", "attachment;filename=\"" + name+"\"");
嗯

下一篇可能要学一下 request 和 respones 的一些讲解（当然也是来自网络的资源我是小白 自己做好 学习笔记就好 ）