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package servlet;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Blob;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.GregorianCalendar;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class Images extends HttpServlet {
private PreparedStatement statement;
public void init() throws ServletException {
Connection connection = // recuperatiopn de la connexion.
String sql = "SELECT * FROM images WHERE id = ? ";
try {
statement = connection.prepareStatement(sql);
} catch (SQLException e) {
e.printStackTrace();
}
}
public void doGet(HttpServletRequest req, HttpServletResponse res) {
String idString = req.getParameter("id");
int id = -1;
try {
id = Integer.parseInt(idString);
} catch (NumberFormatException e1) {
e1.printStackTrace();
return;
}
ResultSet resultSet = null;
try {
statement.setInt(1, id);
resultSet = statement.executeQuery();
if (resultSet.next()) {
Blob blob = resultSet.getBlob("data");
sendImage(res, blob.getBinaryStream(), (int) blob.length());
blob.free();
} else {
// IMAGE introuvable ...
try {
res.getWriter().print("Cette image est introuvable.");
} catch (IOException e) {
}
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
resultSet.close();
} catch (SQLException e) {
}
}
}
private void sendImage(HttpServletResponse res, InputStream in, int length) {
try {
GregorianCalendar calendar = new GregorianCalendar();
calendar.add(GregorianCalendar.DATE, 7);
// cache de 7 jours.
res.setDateHeader("Expires", calendar.getTime().getTime());
res.setContentType("image/jpeg");
res.setContentLength(length);
ServletOutputStream out = res.getOutputStream();
byte[] buffer = new byte[4 * 1024];
while (in.read(buffer) >= 0) {
out.write(buffer);
}
out.flush();
out.close();
} catch (IOException ex) {
// si une erreur se produit au milieu de la réponse
// on envoie le code d'erreur HTTP adéquat
try {
res.sendError(HttpServletResponse.SC_PARTIAL_CONTENT);
} catch (IOException e) {
}
}
}
} |
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