We Keep Coding

How to properly open a png file

I am trying to attach a png file. Currently when I sent the email, the attachment is 2x bigger than the file should be and an invalid png file. Here is the code I currently have:
import com.sendgrid.*;
Attachments attachments = new Attachments();
String filePath = "/Users/david/Desktop/screenshot5.png";
String data = "";
try {
data = new String(Files.readAllBytes(Paths.get(filePath)));
} catch (IOException e) {
}
byte[] encoded = Base64.encodeBase64(data.getBytes());
String encodedString = new String(encoded);
attachments.setContent(encodedString);
Perhaps I am encoding the data incorrectly? What would be the correct way to 'get' the data to attach it?

With respect, this is why Python presents a problem to modern developers. It abstracts away important concepts that you can't fully understand in interpreted languages.
First, and this is a relatively basic concept, but you can't convert arbitrary byte sequences to a string and hope it works out. The following line is your first problem:
data = new String(Files.readAllBytes(Paths.get(filePath)));
EDIT: It looks like the library you are using expects the file to be base64 encoded. I have no idea why. Try changing your code to this:
Attachments attachments = new Attachments();
String filePath = "/Users/david/Desktop/screenshot5.png";
try {
byte[] encoded = Base64.encodeBase64(Files.readAllBytes(Paths.get(filePath)));
String encodedString = new String(encoded);
attachments.setContent(encodedString);
} catch (IOException e) {
}
The only issue you were having is that you were trying to represent arbitrary bytes as a string.

Take a look at the Builder class in the repository here. Example:
FileInputStream fileContent = new FileInputStream(filePath);
Attachments.Builder builder = new Attachments.Builder(fileName, fileContent);
mail.addAttachments(builder.build());

Image byte stream is different when file is read in different ways

Under my Spring 4.3/Maven 3.3 project I have an image file, a PNG file, at:
src/main/resources/images/account.png
I have a util java application file that reads in an image, and it writes it to the database field. The code is as follows:
private static String _accountFilename = "src/main/resources/images/account.png";
private byte[] getByteArrayFromFile(String filename)
{
FileInputStream fileInputStream = null;
File file = new File(filename);
byte[] bFile = new byte[(int) file.length()];
try
{
// convert file into array of bytes
fileInputStream = new FileInputStream(file);
fileInputStream.read(bFile);
fileInputStream.close();
for (int i = 0; i < bFile.length; i++)
{
System.out.print((char) bFile[i]);
}
System.out.println("Done");
}
catch (Exception e)
{
e.printStackTrace();
}
return bFile;
}
public String getImageData(byte[] imageByteArray)
{
Base64.Encoder encoder = Base64.getEncoder();
String base64 = encoder.encodeToString(imageByteArray);
base64 = "data:image/png;base64," + base64;
return base64;
}
The String that comes back from "getImageData" works great. I can put that String in the MySQL database, in a table, and the field is defined as TEXT.
I can pull that base64 encoded data back, and display the image.
Now, If I am calling this code from a Spring Service instead of an application, then the image "src/main/resources/images/account.png" is not found.
After researching on the Net for some time, there are many, many examples of getting a file from "resources" and many of these did not work for me. Since I am in Spring, I tried a few things and finally this worked:
#Value(value = "classpath:images/account.png")
private Resource defaultAccountImage;
private byte[] getByteArrayFromFile(Resource image)
{
InputStream inputStream = null;
byte[] bFile = null;
try
{
bFile = new byte[(int) image.contentLength()];
// convert file into array of bytes
inputStream = image.getInputStream();
inputStream.read(bFile);
inputStream.close();
for (int i = 0; i < bFile.length; i++)
{
System.out.print((char) bFile[i]);
}
System.out.println("Done");
}
catch (Exception e)
{
e.printStackTrace();
}
return bFile;
}
private String getImageData(byte[] imageByteArray)
{
Base64.Encoder encoder = Base64.getEncoder();
String base64 = encoder.encodeToString(imageByteArray);
base64 = "data:image/png;base64," + base64;
return base64;
}
public String getDefaultAccountImage()
{
byte[] accountImage = getByteArrayFromFile(defaultAccountImage);
String fileString = getImageData(accountImage);
return fileString;
}
When I look at the String/Image data between the first way with the standalone java app, and the second way with the #Value and inputstream, there is a definite different in the string data.
part of the string data is similar, but then it drastically changes, and they don't match. As a result the text data for the image from the second method doesn't display as an image.
So, I was hoping I could get this image text data, and it would be the same, but it is not. If I can use my web-service, which calls the business service which calls this ImageUtil code where I use the #Value to get the image resource and it saves the text string correctly, that would be great.
If you have any advice, I would very much appreciate it. Thanks!
UPDATE 1:
This is a multi-maven project:
parent-project
entity
dao
service
ws
When I run my test code within the Service layer, the suggested solution works great! The images are found and the byte string gets loaded as it should be. And then I compiled the code into a jar.
The entity.jar gets created first.
The dao.jar gets created and pulls in the entity.jar.
The service.jar gets created and pulls in the dao.jar. This layer also has the /resources/images/account.png file. But this image is now in the jar.
The ws.WAR file pulls in the service.jar file ...
so the code in the answer does not find the image in the resources.
When I run the tests from the ws layer, I get a FileNotFoundException.
So ... now I am researching on how to get an image from jar ...
Does this change how I should be getting my image byte array?

You can get the file from the Resource, and proceed like the first example which works. Seems redundant, but if you can get the file, then you can test a number of things:
Write the file to disk and check the content
Write the file to disk and compare the sizes, etc.
import java.io.File;
import java.io.FileInputStream;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.core.io.Resource;
#Value(value = "classpath:images/account.png")
private Resource defaultAccountImage;
private byte[] getByteArrayFromFile(Resource image) {
FileInputStream fileInputStream = null;
byte[] bFile = null;
try {
File file = image.getFile();
bFile = new byte[(int) file.length()];
// convert file into array of bytes
fileInputStream = new FileInputStream(file);
fileInputStream.read(bFile);
fileInputStream.close();
for (int i = 0; i < bFile.length; i++) {
System.out.print((char) bFile[i]);
}
System.out.println("Done");
} catch (Exception e) {
e.printStackTrace();
}
return bFile;
}

JAVA encode/decode base 64 and render it on browser or save it to file

I am sending an image after base64 encoding from my JSP to a servlet using AJAX. At the servlet side, I am trying to decode and save it to either a file or render to a browser.
I am getting an empty image. Here is my servlet side code
String imageStr = request.getParameter("image");
byte[] decoded = Base64.decodeBase64(imageStr);
String path = "D:\\myImage.png";
try {
OutputStream out1 = new BufferedOutputStream(new FileOutputStream(path));
out1.write(decoded);
} finally {
}
I get a the image, but its empty.

Try closing the stream, it should flush all buffered data:
String imageStr = request.getParameter("image");
byte[] decoded = Base64.decodeBase64(imageStr);
String path = "D:\\myImage.png";
OutputStream out1 = null;
try {
out1 = new BufferedOutputStream(new FileOutputStream(path));
out1.write(decoded);
} finally {
if (out1 != null) {
*out1.close();*
}
}
And make sure the decoded array really contains some data.

How do i convert blob to image displayed in a JSP

I am trying to retrieve images from database.
Currently i was able to show :
`com.mysql.jdbc.Blob#2aba2aba `
in my jsp output.
May i know how to convert that into an image?
i have use the below to call out the above
photo[i].getPhotoFileData();

This is more of an issue with the way HTML documents work than with your JSP. You need to understand that HTML doesn't embed images directly. Instead, it uses <img> tags to reference images hosted at different URLs.
In order to display an image stored in a database on an HTML page you're going to need a separate servlet that can handle requests for the image. Your JSP should render an HTML document like the following:
<html>
<head>
...
</head>
<body>
...
<img src="www.mydomain.com/images/1234.png" />
...
</body>
</html>
Then you would create a separate servlet to handle all the requests to /images which would make a database call and send the raw bytes from the blob it gets back to the response's output stream. Make sure you also set the Content-Type header correctly based on what image encoding you're using.
In order to send the image back to the requester you have one of two options. You can get the blob's bytes as an array and write that to the OutputStream (e.g. out.write(blob.getBytes(0,blob.length());). Or you can use the getBinaryStream() method and then copy bytes from the InputStream to the OutputStream. Here's an example of that:
public static void copy(Blob from, OutputStream to)
throws IOException {
byte[] buf = new byte[4096];
try(InputStream is = from.getBinaryStream()) {
while (true) {
int r = is.read(buf);
if (r == -1) {
break;
}
to.write(buf, 0, r);
}
}
}
NB: This code has not been tested or even compiled, it should only be used as a starting point.

You're getting a Blob object - not it's contents. If you want to get raw byte data you have to ask the Blob object for it, e.g.:
Blob blob = photo[i].getPhotoFileData();
byte[] data = blob.getBytes(0, blob.length());
If you want to create an image on the fly, then just call:
BufferedImage img = ImageIO.read(new ByteArrayInputStream(data));
You can then save the image or ... actually I don't know what else. Thing. Stuff. Display it. Print. Limitless possibilities! Just like at zombo.com!

first convert blob to input stream to string . then use that String instead of image URL .
Converting blob to String
try {
Blob blob = staticOffer.getImage(); //blob of image from db
strOut = new StringBuffer();
String aux;
BufferedReader br;
br = new BufferedReader(new InputStreamReader(blob.getBinaryStream()));
while ((aux=br.readLine())!=null) {
strOut.append(aux);
}
offerPicStr = strOut.toString();
} catch (Exception e) {
e.printStackTrace();
}
Now use that string it html/jsp in following way
<img src="data:image/jpeg;base64,${offerPicStr}" width="100" height="100"></img>

call local image in drawable with html (WebView)

This question has been asked few times in forums, but in my code, i can't display my image. I think it's not the right method :
webViewContact.loadData(db.getParametres().get(0).getInformationParam(), "text/html", "utf-8");
getInformationParam() recup the HTML code, like :
<img src=\\"file:///android_asset/logoirdes_apropos.jpg\\"/> <b>Test</b>
My image file is in drawable, how i can display it ?

There are restrictions about the HTML loaded with loadData() can do. Suggest using loadUrl:
webViewContact.loadUrl("file:///android_asset/" + db.getParametres().get(0).getInformationParam())
You can try the following code, and your file will be at: htmlFile. You can certainly do it in UI thread for now, but you might consider to move this to a AsyncTask later in real production if the file is huge.
String directory = Environment.getExternalStoragePublicDirectory("html_cache");
Writer output;
try {
directory.mkdir();
File htmlFile = new File(directory + File.separator + "give_a_name.html");
String content = db.getParametres().get(0).getInformationParam();
// assumes default encoding is OK!
output = new BufferedWriter(new FileWriter(htmlFile));
output.write( aContents );
}
finally {
output.close();
}