23

There is a way to convert an InputStream to a String, and encode it to base64, right?

In my function, I get InputStream parameter, and need to insert it into the BLOB field in my Oracle database table.

Is there a way to do that?

(My database object contains string field to save the image, but I don't find any way to convert the InputStream to string in base 64 format.)

Lii
  • 11,553
  • 8
  • 64
  • 88
foo
  • 443
  • 2
  • 8
  • 22
  • 1
    Did you try anything at all? If your InputStream contains image data, don't use a ``String`` though, use ``byte[]``. – f1sh Mar 08 '17 at 09:51
  • Ok, what is it mean? I need to change this field to Byte[]? and how can I convert it to Byte[] from inputStream? thanks! – foo Mar 08 '17 at 09:56

5 Answers5

32

There is nice way to do this is using IOUtils to convert the InputStream into a Byte Array...

something like

    InputStream is;
    byte[] bytes = IOUtils.toByteArray(is);

Here you can use Base64 to convert Byte Array to String.

Sample Code

    String encoded = Base64.getEncoder().encodeToString(bytes);

Now you can use your String.

Raj Rusia
  • 728
  • 10
  • 15
  • `IOUtils` is not found, consult this https://stackoverflow.com/questions/24578243/cannot-resolve-symbol-ioutils – joe_inz Oct 12 '21 at 14:38
30

You can try something like this using the Base64 API.

InputStream finput = new FileInputStream(file);
byte[] imageBytes = new byte[(int)file.length()];
finput.read(imageBytes, 0, imageBytes.length);
finput.close();
String imageStr = Base64.encodeBase64String(imageBytes);

Use this:

http://commons.apache.org/proper/commons-codec/archives/1.9/apidocs/org/apache/commons/codec/binary/Base64.html

mhasan
  • 3,703
  • 1
  • 18
  • 37
  • new FileInputStream need to get file - I don't have file name.... I need to set inputStream.... – foo Mar 08 '17 at 10:09
  • that should be ok as long as you have InputStream with you . you use the mentioned logic – mhasan Mar 08 '17 at 10:10
  • Base64.DEFAULT - get compilation error- DEFAULT is not field. what shuld I need to do? – foo Mar 08 '17 at 10:11
3

The simplest way would be to use IOUtils from apache-commons to do that:

String result= IOUtils.toString(inputStream, ENCODING);

From the documentation:

toString(byte[] input, String encoding) Gets the contents of a byte[] as a String using the specified character encoding.

After that To Encode/Decode in Base64:

// Encode 
String resultBase64Encoded = Base64.getEncoder().encodeToString(result.getBytes("utf-8"));


// Decode
byte[] asBytes = Base64.getDecoder().decode(resultBase64Encoded);
String resultAsStringAgain= String(asBytes, "utf-8")

Note: I'm assuming you use JDK 8 for the Encode/Decode part.

Apparently the OP wants just to persist an InputStream to the DB. You can do that directly using JDBC:

InputStream inputStream = ......;
String sql = "INSERT INTO TABLE_NAME(COLUMN_NAME) values (?)";
PreparedStatement statement = connection.prepareStatement(sql);
statement.setBlob(1, inputStream);
statement.executeUpdate();
Alboz
  • 1,833
  • 20
  • 29
  • @f1sh I know that but this is what the the OP asked for. – Alboz Mar 08 '17 at 10:10
  • so what can I do? where do I put the image data before insert it to DB blob? – foo Mar 08 '17 at 10:12
  • @foo If all you want to do is to save an InputStream into the DB you can do it directly without transforming it to anything else... – Alboz Mar 08 '17 at 10:18
  • @foo see me updated answer about How to persist an InputStream as Blob directly to the DB – Alboz Mar 08 '17 at 10:24
  • To mee this is much more memory efficient way to do it, the byte[] in the accepted answer will eat it. You dont need a temp space to persist a stream. – mcvkr Aug 09 '18 at 20:49
2

As I mentioned, you shouldn't use String for binary data. The base64-encoded data can be stored as a String though. But since your database column is a blob, I would continue to work with a byte[].

Use IOUtils to get a byte[] from the InputStream:

byte[] bytes = IOUtils.toByteArray(yourInputStream);
byte[] encoded = java.util.Base64.getEncoder().encode(bytes);

Then write it to the database. Writing a blob using jdbc and a PreparedStatement looks like this:

yourPreparedStatement.setBytes(nIndex, encoded);
f1sh
  • 11,489
  • 3
  • 25
  • 51
1

In case someone is looking for solution without external libraries. Java8 adds Base64 utility class which contains getEncoder() method. Java9 adds fancy method on InputStream called readAllBytes() Link to api

So now you without any external libraries your code may look like

import java.io.InputStream;
import java.util.Base64;

public String encode(InputStream stream) throws IOException {
  final var bytes = stream.readAllBytes();

  return Base64.getEncoder().encodeToString(bytes);
}
emptak
  • 429
  • 6
  • 11