环境mysql+tomcat:
<1>先在mysql下建立如下的table. 并insert图像
mysql.sql文件如下:
CREATE TABLE photo (
photo_no int(6) unsigned NOT NULL auto_increment,
image blob,
PRIMARY KEY (`photo_no`)
)
<2>把show.jsp放在tomcat的任意目录下. show.jsp作用:从数据库中读出blob,并产生image/jpg.
show.jsp文件如下:
<%@ page contentType="text/htmlcharset=gbk" %>
<%@ page import="java.io.*"%>
<%@ page import="java.sql.*, javax.sql.*" %>
<%@ page import="java.util.*"%>
<%@ page import="java.math.*"%>
<%
String photo_no = request.getParameter("photo_no")
//mysql连接
Class.forName("com.mysql.jdbc.Driver").newInstance()
String URL="jdbc:mysql://localhost:3306/job?user=root&password=111111"
Connection con = DriverManager.getConnection(URL)
//oracle连接
//String URL="jdbc:oracle:thin@localhost:1521:orcl2"
//user="system"
//password="manager"
//Connection con = DriverManager.getConnection(URL,user,password)
try{
// 准备语句执行对象
Statement stmt = con.createStatement()
String sql = " SELECT * FROM PHOTO WHERE photo_no = "+ photo_no
ResultSet rs = stmt.executeQuery(sql)
if (rs.next()) {
Blob b = rs.getBlob("photo_image")
long size = b.length()
//out.print(size)
byte[] bs = b.getBytes(1, (int)size)
response.setContentType("image/jpeg")
OutputStream outs = response.getOutputStream()
outs.write(bs)
outs.flush()
rs.close()
}
else {
rs.close()
response.sendRedirect("./images/error.gif")
}
}
finally{
con.close()
}
%>
<3>把如下文件放在show.jsp的同一目录下.
index.html文件如下:
<HTML>
<HEAD>
<TITLE>图像测试 </TITLE>
</HEAD>
<BODY>
<TABLE>
<TR>
<TD>图像测试</TD>
</TR>
<TR>
<TD><img src="show.jsp?photo_no=2"></TD>
</TR>
</TABLE>
</BODY>
</HTML>
2008-11-02 15:321.序数据库应用程序,特别是基于WEB的数据库应用程序,常会涉及到图片信息的存储和显示。
通常我们使用的方法是将所要显示的图片存在特定的目录下,在数据库中保存相应的图片的名称,在JSP中建立相应的数据源,利用数据库访问技术处理图片信息。但是,如果我们想动态的显示图片,上述方法就不能满足需要了。我们必须把图片存入数据库,然后通过编程动态地显示我们需要的图片。实际 *** 作中,可以利用JSP的编程模式来实现图片的数据库存储和显示。
2. 建立后台数据库
if exists (select * from dbo.sysobjects
where id = object_id(N'[dbo].[p]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)
drop table [dbo].[p]
GO
CREATE TABLE [dbo].[p] (
[picid] [int] IDENTITY (1, 1) NOT NULL ,
[picname] [varchar] (50) COLLATE Chinese_PRC_CI_AS NULL ,
[pic] [image] NULL
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
GO
3.向数据库存储二进制图片
启动Dreamweaver MX后,新建一个JSP文件。其代码如下所示。
<%@ page contentType="text/htmlcharset=gb2312"%>
<%
String path = request.getContextPath()
String basePath = request.getScheme()+"://"+request.getServerName()
+":"+request.getServerPort()+path+"/"
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'InputImage.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<form action="testimage.jsp" method="POST"><br>
题目<input name="picname" type="text"><br>
图片<input name="pic" type="file"><br>
<input type="Submit" name="button1" value="提交"><br>
</form>
</body>
</html>
将此文件保存为InputImage.jsp文件,其中testimage.jsp文件是用来将图片数据存入数据库的,具体代码如下所示:
<%@ page contentType="text/htmlcharset=gb2312"%>
<%@ page import="java.sql.*" %>
<%@ page import="java.util.*"%>
<%@ page import="java.text.*"%>
<%@ page import="java.io.*"%>
<jsp:useBean id="conn" scope="page" class="dbconn.DBResult"/>
<%
String path = request.getContextPath()
String basePath = request.getScheme()+"://"+request.getServerName()+
":"+request.getServerPort()+path+"/"
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'testimage.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<%
request.setCharacterEncoding("gb2312")
//建立Statement对象
String picname=request.getParameter("picname")
String pic=request.getParameter("pic")
//获得所要显示图片的标题、存储路径、内容,并进行中文编码
FileInputStream str=new FileInputStream(pic)
String sql="insert into p(picname,pic) values(?,?)"
PreparedStatement pstmt=conn.getPreparedStatement(sql)
pstmt.setString(1,picname)
pstmt.setBinaryStream(2,str,str.available())
pstmt.execute()
//将数据存入数据库
out.println("Success,You Have Insert an Image Successfully")
%>
</body>
</html>
4. 网页中动态显示图片
接下来我们要编程从数据库中取出图片,其代码如下所示。
<%@ page contentType="text/htmlcharset=gb2312"%>
<%@ page import="java.sql.*" %>
<%@ page import="java.util.*"%>
<%@ page import="java.text.*"%>
<%@ page import="java.io.*"%>
<jsp:useBean id="conn" scope="page" class="dbconn.DBResult"/>
<%
String path = request.getContextPath()
String basePath = request.getScheme()+"://"+request.getServerName()+
":"+request.getServerPort()+path+"/"
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'testimageout.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<%
int id= Integer.parseInt(request.getParameter("picid"))
String sql = "select pic from p WHERE picid="+id
ResultSet rs=conn.getResult(sql)
while(rs.next())
{
ServletOutputStream sout = response.getOutputStream()
//图片输出的输出流
InputStream in = rs.getBinaryStream(1)
byte b[] = new byte[0x7a120]
for(int i = in.read(b)i != -1)
{
sout.write(b)
//将缓冲区的输入输出到页面
in.read(b)
}
sout.flush()
//输入完毕,清除缓冲
sout.close()
}
%>
</body>
</html>
将此文件保存为testimageout.jsp文件。下一步要做的工作就是使用HTML标记:
<%@ page contentType="text/htmlcharset=gb2312"%>
<%@ page import="java.sql.*" %>
<%@ page import="java.util.*"%>
<%@ page import="java.text.*"%>
<%@ page import="java.io.*"%>
<jsp:useBean id="conn" scope="page" class="dbconn.DBResult"/>
<%
String path = request.getContextPath()
String basePath = request.getScheme()+"://"+request.getServerName()+
":"+request.getServerPort()+path+"/"
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'lookpic.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<%
String sql = "select * from p"
ResultSet rs=conn.getResult(sql)
while(rs.next())
{
%>
<ccid_file values="testimageout" % />" width="100" height="100">
<br>
<%
}
rs.close()
%>
</body>
</html>
版权归原版所有!!!
数据库不能保存图像,但是能保存图像名,我给你个思路,用户上传后使用uid方法将图片重命名,然后将新的名称存在数据库,图片保存在一个已知路径,然后页面加载只需要将图片src设置成"路径/数据库查询结果。(建议通过id查询)"欢迎分享,转载请注明来源:内存溢出
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