SHINERAJ ARATHIL SHINERAJ ARATHIL - 2 months ago 12
Java Question

Unable to show images in JSP from database using servlet

I am trying to fetch and display , images saved as blob on the JSP from mysql database using servlet. I wrote this code referring many websites and still , its not working. I am not getting any type of errors. its showing like this

enter image description here

I have created table using

create table contacts(id int not null auto_increment,
name varchar(40),
second varchar(40),
photo blob,
primary key(id));


This my Servlet DisplayServlet.java

@WebServlet("/DisplayServlet")
public class DisplayServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
Connection conn = null;
PreparedStatement stmt = null;
ResultSet rs = null;
public void init() throws ServletException {

}

public DisplayServlet() {
super();
}


protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}

/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

String imageId = request.getParameter("id");
System.out.println(imageId);
InputStream sImage;



// Check if ID is supplied to the request.
if (imageId == null) {
// Do your thing if the ID is not supplied to the request.
// Throw an exception, or send 404, or show default/warning image, or just ignore it.
response.sendError(HttpServletResponse.SC_NOT_FOUND); // 404.
return;
}

try{
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/projectbuy", "root","root");
stmt = conn.prepareStatement("select photo from contacts where id=" + imageId);
rs = stmt.executeQuery();
if(rs.next()){
System.out.println("Inside RS");
byte[] bytearray = new byte[1048576];
int size=0;
sImage = rs.getBinaryStream(4);
response.reset();
response.setContentType("image/jpeg");
while((size = sImage.read(bytearray)) != -1 ){
response.getOutputStream().
write(bytearray,0,size);
}
}

} catch (Exception e){
e.printStackTrace();
}
}


}

Here is my jsp page , imagedemo.jsp

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>

<h1>Hello World!</h1>


<img src="DisplayServlet?id=1" height="150px" width="150px" alt="ProfilePic">

</body>
</html>


Finally this is my xml file

<servlet-mapping>
<servlet-name>action</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>

<servlet>
<servlet-name>DisplayServlet</servlet-name>
<servlet-class>DisplayServlet</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>DisplayServlet</servlet-name>
<url-pattern>/DisplayServlet/*</url-pattern>
</servlet-mapping>

Answer

You're selecting only one column:

stmt = conn.prepareStatement("select photo from contacts where id=" + imageId);

but later trying to retrieve 4th:

sImage = rs.getBinaryStream(4);

And you have no flush() call afer writing loop. Also it's a good idea to use connection from pool instead of instantiating it directly from driverManager, and to close it after work.

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