从MySql数据库读取图片

最新推荐文章于 2024-10-15 15:26:55 发布

原创最新推荐文章于 2024-10-15 15:26:55 发布 · 1.5k 阅读

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CC 4.0 BY-SA版权

本文介绍了一个使用JSP从数据库检索并显示图片的示例。通过连接数据库并执行SQL查询，可以将图片路径提取出来，并利用Java IO操作读取图片文件，最终将其作为响应发送给客户端进行展示。

create table image( content varchar(10) , image varchar(50) );

testimage.jsp

<%@    page    contentType= "text/html;charset=gb2312"%>
<%@    page    import= "java.sql.* "    %>
<%@    page    import= "java.util.* "%>
<%@    page    import= "java.text.* "%>
<%@    page    import= "java.io.* "%>
<%@ page import="javax.servlet.http.*,javax.servlet.*" %>
<html>
<body>
<%Class.forName( "com.mysql.jdbc.Driver");
String url= "jdbc:mysql://localhost:3306/school";
Connection conn= DriverManager.getConnection(url,"root","root");
String sql = "select image from image where content='1.jpg'";
Statement stmt=null;
ResultSet rs=null;
response.setContentType("application/jpg");
response.setHeader("Content-disposition","attachment;filename=sample.jpg");
out.clearBuffer();
out = pageContext.pushBody();
ServletOutputStream sout =  response.getOutputStream();
BufferedInputStream buf=null;
FileInputStream in=null;
File file=null;
try{
stmt=conn.createStatement();
rs=stmt.executeQuery(sql);
while(rs.next()){
String path=rs.getString("image");
file=new File(path);
in=new FileInputStream(file);
buf=new BufferedInputStream(in);
int bytes=0;
while((bytes=in.read())!=-1){
   sout.write(bytes);
}
}
conn.close();
stmt.close();
}catch(SQLException e){
   System.out.println(e);
   }
   catch(IOException e){
   System.out.println("Ing!");
   }finally{
   if(sout!=null)
   sout.close();
   if(buf!=null)
   buf.close();
   }
%>
</body>
</html>

testimage.html:

<HTML>          <HEAD>
<TITLE>Image File</TITLE>
<meta http-equiv= "Content-Type" content= "text/html;charset=gb2312">
</HEAD>
<BODY>
<img src="http://localhost:8080/ServletTest/testimage.jsp" />
</BODY>
</HTML>

本人亲测，可行！结果如上:

当然要完成一次插入多个图片也就好办了：（如下，完成插入4张图片）

数据库image内容:

------------------------------------

content image

------------------------------------

1.jpg C:\images\1.jpg

2.jpg C:\images\2.jpg

3.jpg C:\images\3.jpg

4.jpg C:\images\4.jpg

------------------------------------

<%@ page language="java" pageEncoding="gb2312" %>
<%@ page contentType="text/html;charset=gb2312" %>
<%request.setCharacterEncoding("gb2312");%>
<%@ page import="java.util.*,java.lang.*,java.sql.*" %>
<%@ page errorPage="error.html" %>
<html>
<head><meta http-equiv=Content-Type content="text/html;charset=gb2312"></head>
<body>
<%int i=1;
while(i<5){
 String srcstring="http://localhost:8080"+request.getContextPath()+"/testimageout.jsp?id="+Integer.toString(i); %>
<img border="1" src="<%=srcstring %>" alt="ok" >
<%i++; }%>
</body></html>

这时只要在testimageout.jsp页面中获取一个参数即可：

String id=request.getParameter("id");

String sql = "select image from image where content like '"+id+"%'";

效果如下：