用JSP从数据库中读取图片并显示在网页上
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/html; charset=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>