How to retrieve the original file

Question

In Java JSP, I'm using input stream and BLOB datatype to write any type of file into the database. I want to retrieve the BLOB file. How should I go about retrieving it? I tried using select statement and got this (material column).

can you show some code, how you are inserting into the database ? — no one, May 13 '16 at 17:12
[link](http://stackoverflow.com/questions/37203046/retrieving-file-upload-from-database) check the code — , May 13 '16 at 17:53

score 2 · Answer 1 · edited May 23 '17 at 10:29

2

Using a ResultSet, you can retrieve a java.sql.Blob instance:

Blob blob = resultSet.getBlob("MATERIAL");

Then you can open an input stream:

InputStream input = blob.getBinaryStream();

And write it to a file as described in Is it possible to create a File object from InputStream

edited May 23 '17 at 10:29

Community

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answered May 13 '16 at 18:10

andrucz

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how to show that input stream in jsp,after retrieving the value of blob material? – May 13 '16 at 19:40
do you have to show it or be able to download it? what do you want to do if the file can't be showed? – andrucz May 16 '16 at 18:29
i solved this without using blob, for downloads igave the filepath and it works – May 18 '16 at 10:16

score 0 · Answer 2 · answered May 13 '16 at 18:55

Getting the Blob from the table:

try (ResultSet rs = statement.executeQuery(query)) {
    if(rs.next()) {
        fileBlob = rs.getBlob(1);
    }
}

Saving the contents of the Blob into a new file:

try (InputStream ipStream = fileBlob.getBinaryStream(1, fileBlob.length());
        OutputStream opStream = new FileOutputStream(new File("path/to/file"))) {                        
    int c;
    while ((c = ipStream.read()) > -1) {
        opStream.write(c);
    }
}

How to retrieve the original file

2 Answers2