Question

ShowImage.java

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package form;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.sql.Blob;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class CriminalPic extends HttpServlet {
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {

        try {
            Class.forName("oracle.jdbc.driver.OracleDriver");
            Connection con = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:xe", "epolicia", "admin");
           PreparedStatement ps = con.prepareStatement("select * from CRIMINAL_PIC where CRIMINAL_ID = ?");
            String id = request.getParameter("id");
            ps.setString(1,id);
            ResultSet rs = ps.executeQuery();
            rs.next();
            Blob  b = rs.getBlob("PICTURE");
            response.setContentType("image/jpeg");
            response.setContentLength( (int) b.length());
            InputStream is = b.getBinaryStream();
            OutputStream os = response.getOutputStream();
            byte buf[] = new byte[(int) b.length()];
            is.read(buf);
            os.write(buf);
            os.close();
        }
        catch(Exception ex) {
            PrintWriter out = response.getWriter();
             out.print("../pics/thief.jpg");
        }
    }

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

show.jsp

<%out.print("<img width='100%' height='200' src=../CriminalPic?id=" +rs.getString(1) + "></img>");%>

I’m trying to display the image from the database using Servlet. It works fine, but for the alternative, when it got any exception, for that case, it must show the alternative image, whose path has been given. But, it doesn’t display anything. Need help !!

Answer 1

Do you call the CriminalPic Servlet from a img tag’s src attribute in HTML ?
If yes, then here is my idea.

public class CriminalPic extends HttpServlet {
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
    InputStream is = null;
    OutputStream os = response.getOutputStream();
    try {
        Class.forName("oracle.jdbc.driver.OracleDriver");
        Connection con = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:xe", "epolicia", "admin");
       PreparedStatement ps = con.prepareStatement("select * from CRIMINAL_PIC where CRIMINAL_ID = ?");
        String id = request.getParameter("id");
        ps.setString(1,id);
        ResultSet rs = ps.executeQuery();
        rs.next();
        Blob  b = rs.getBlob("PICTURE");
        response.setContentType("image/jpeg");
        response.setContentLength( (int) b.length());
        is = b.getBinaryStream();
        byte buf[] = new byte[(int) b.length()];
        is.read(buf);
        os.write(buf);
    }
    catch(Exception ex) {
        File file = new File(getServletContext.().getRealPath("/pics/thief.jpg"));
        FileInputStream fis = new FileInputStream(file);
        int bytes;
        while ((bytes = fis.read()) != -1) {
        os.write(bytes);
        }
    }