Display images on a webpage

[Kevin Moseley]

Hey everyone,
I am trying to create a web application and want to store image
information in a mysql database and store the images on a filesystem. I
am also using struts and I am looking for the best way to do this. I
want to store the images outside the servlet context so that if I
redeploy I won't lose the images.
Let me know if you have any questions and thank you in advance for your
help.

--
Kevin
***************************************************************
"The trouble with programmers is that you can never tell what a
programmer is doing until it's too late."
-Seymour Cray

 

[John B. Matthews]

I am trying to create a web application and want to store image
information in a mysql database and store the images on a filesystem.

Keeping the image data with the image metadata make the former _much_
easier to find in connection with the latter. Storing the image data in
the file system is conceptually appealing, but it requires keeping a
global root path, as well as a relative path name for each image. Such
names are fragile, OS dependent, and entirely outside the aegis of the
database's referential integrity constraints.

It's possible that you're assuming the file system to be faster. You may
have to benchmark your particular mix of image size and number to decide
if going outside the database is worth the effort.

[...]

I want to store the images outside the servlet context so that if I
redeploy I won't lose the images. Let me know if you have any
questions

[...]

What does "redeploy" mean in this context? Different server? Different
servlet container? Different database? How does "store ... outside"
imply "won't lose the images?"

 

[Msj121]

I am trying to create a web application and want to store image
information in a mysql database and store the images on a filesystem.

Keeping the image data with the image metadata make the former _much_
easier to find in connection with the latter. Storing the image data in
the file system is conceptually appealing, but it requires keeping a
global root path, as well as a relative path name for each image. Such
names are fragile, OS dependent, and entirely outside the aegis of the
database's referential integrity constraints.

It's possible that you're assuming the file system to be faster. You may
have to benchmark your particular mix of image size and number to decide
if going outside the database is worth the effort.

[...]> I want to store the images outside the servlet context so that if I

redeploy I won't lose the images. Let me know if you have any
questions

[...]

What does "redeploy" mean in this context? Different server? Different
servlet container? Different database? How does "store ... outside"
imply "won't lose the images?"

Hi,
I am assuming at the moment that re-deploy means restart, and you
don't want it stored in temporary memory.

Thus if it is stored on mysql then I see no issue as to why re-
deployment would lose the data, so I assume the file storage is a
backup - why not back it up on a weekly basis (or whatever it might
be).
If you really wanted it in a file system you could save some time
by using EJB (Enterprise Java Bean), but the "best" part of this is
that you could use an encoder (ie: XMLEncoder?) to encode the object
to save it to a file. Btw, I may suggest a custom XMLEncoder (or
another method of Serialization as the Java version is very simple -
but it relies on numerous listeners which I think is dynamic, but in-
efficient). Do beware though as XMLEncoder can be annoying to get
running even though there are few lines of code....

I was just thinking that perhaps the file system was so you could
personally view the images? You might want to check
http://java.sun.com/docs/books/tutorial/2d/images/index.html - this
should give you all of the information.


For the mysql you need a table of course - my suggestion:
CREATE TABLE images (
ID int NOT NULL AUTO_INCREMENT PRIMARY KEY,
NAME VARCHAR(32),
IMAGE BLOB
);

http://www.java2s.com/Code/Java/Database-SQL-JDBC/BlobJDBCdealswithBinaryData.htm
for an example of reading and writing images with mysql and java.

MSJ121

 

[Kevin Moseley]

I am trying to create a web application and want to store image
information in a mysql database and store the images on a filesystem.

Keeping the image data with the image metadata make the former _much_
easier to find in connection with the latter. Storing the image data in
the file system is conceptually appealing, but it requires keeping a
global root path, as well as a relative path name for each image. Such
names are fragile, OS dependent, and entirely outside the aegis of the
database's referential integrity constraints.

It's possible that you're assuming the file system to be faster. You may
have to benchmark your particular mix of image size and number to decide
if going outside the database is worth the effort.

[...]> I want to store the images outside the servlet context so that if I

redeploy I won't lose the images. Let me know if you have any
questions

[...]

What does "redeploy" mean in this context? Different server? Different
servlet container? Different database? How does "store ... outside"
imply "won't lose the images?"

Hi,
I am assuming at the moment that re-deploy means restart, and you
don't want it stored in temporary memory.

Thus if it is stored on mysql then I see no issue as to why re-
deployment would lose the data, so I assume the file storage is a
backup - why not back it up on a weekly basis (or whatever it might
be).
If you really wanted it in a file system you could save some time
by using EJB (Enterprise Java Bean), but the "best" part of this is
that you could use an encoder (ie: XMLEncoder?) to encode the object
to save it to a file. Btw, I may suggest a custom XMLEncoder (or
another method of Serialization as the Java version is very simple -
but it relies on numerous listeners which I think is dynamic, but in-
efficient). Do beware though as XMLEncoder can be annoying to get
running even though there are few lines of code....

I was just thinking that perhaps the file system was so you could
personally view the images? You might want to check
http://java.sun.com/docs/books/tutorial/2d/images/index.html - this
should give you all of the information.


For the mysql you need a table of course - my suggestion:
CREATE TABLE images (
ID int NOT NULL AUTO_INCREMENT PRIMARY KEY,
NAME VARCHAR(32),
IMAGE BLOB
);

http://www.java2s.com/Code/Java/Database-SQL-JDBC/BlobJDBCdealswithBinaryData.htm
for an example of reading and writing images with mysql and java.

MSJ121

I apologize for not being clearer. I am new to java,struts, tomcat,
and hibernate. I guess I am curious as to which is better, storing
images in a database or using the file system and storing the file
information in the database. What I want to do is have users upload
photos and when they open their profile they can view the files they
have uploaded. I am using struts and hibernate and I don't know how to
pull multiple images in the jsp.
What is the best practice for uploading and viewing images? I have
googled it and it seems the consensus is to store files on the file
system and use action files to display the images using input streams to
display the images. What is causing me problems how to display on the
page load.
When I meant reload is if upload a new .war file doesn't is overwrite
the folder when I restart tomcat and if my images were in there they
would be lost.

--
Kevin
***************************************************************
"The trouble with programmers is that you can never tell what a
programmer is doing until it's too late."
-Seymour Cray

 

[Arne Vajhøj]

I apologize for not being clearer. I am new to java,struts, tomcat,
and hibernate. I guess I am curious as to which is better, storing
images in a database or using the file system and storing the file
information in the database. What I want to do is have users upload
photos and when they open their profile they can view the files they
have uploaded. I am using struts and hibernate and I don't know how to
pull multiple images in the jsp.
What is the best practice for uploading and viewing images? I have
googled it and it seems the consensus is to store files on the file
system and use action files to display the images using input streams to
display the images. What is causing me problems how to display on the
page load.
When I meant reload is if upload a new .war file doesn't is
overwrite the folder when I restart tomcat and if my images were in
there they would be lost.

You can store the images 3 places:
a) database
b) file system in directory served by Tomcat
c) file system in directory not served by Tomcat

It can be implemented by:
a) have your pages generate <img src="ImageServlet?imgid=177">
have ImageServlet set MIME type appropriate, retrieve BLOB from
database and write to output
b) have your page generate <img src="images/img177.jpg">
c) have your pages generate <img src="ImageServlet?imgid=177">
have ImageServlet set MIME type appropriate, read image from
file system and write to output

Which one to chose ?

#b has some problems:
- redeployment that you mention
- lack of security by user
so it is either #a or #c.

It is a well known discussion.

Many people swear that images in the database will kill the
database performance.

And putting images in an Access 95 database on Windows 95 on
a 150 MHz Pentium box indeed did kill database performance.

But a few things ha changed in software and hardware since then.

With a good database system then there should not be any problem
having images of small-medium size in the database.

I once made som tests to verify and performance was OK.

So I will suggest going for #a.

Arne