如何从源文件夹中读取图像作为FileInputStream？

Question

I have been trying to upload image to database. So I made a browse button to go through directories and get the image. Suppose if no image is selected, a default image will be uploaded to the database. The image is stored in a folder named 'resources' under source folder.In the image, helper is the folder containting .java files and below is the resources folder I am uploading the image as FileInputStream and the code is

File pic=new File(imgloc);
FileInputStream fis=new FileInputStream(pic);

If the image is not selected to upload a default image my code is

File pic=new File(this.getClass().getResource("/resources/profile1.png").getFile());
FileInputStream fis=new FileInputStream(pic);

And my query to database is

    ps.setBinaryStream(1,fis ,(int) pic.length()); //While substituing for '?' in query 

After build to jar it produce FileNotFoundException when trying to add default image. May be the question is asked several times I didn't find solution in that. I want read the image as file..Thanks in advance.

Answer 1

to help illustrate I create a project with a source directory

src

below source I had a package starthere with a class Main

I create another source directory xxx and put in a file a.txt

I also created under xxx a directory called text and put in a file named b.txt

Also I created under src a directory called other and put in a file called c.txt

My code is

    URL url = Main.class.getResource("/a.txt");
    System.out.println(url);
    URL url2 = Main.class.getResource("/text/b.txt");
    System.out.println(url2);
    URL url3 = Main.class.getResource("/other/c.txt");
    System.out.println(url3);

and my output is

D:\\temp>java -cp ab.jar starthere.Main

jar:file:/D:/temp/ab.jar!/a.txt

jar:file:/D:/temp/ab.jar!/text/b.txt

jar:file:/D:/temp/ab.jar!/other/c.txt

edit

As you are not wanting to use a File, but simply the InputStream, you can use

InputStream fis = Main.class.getResourceAsStream("/a.txt");

and then set using ps.setBinaryStream(1, fis);

Answer 2

Consider following package structure

/
/testing_package
/testing_package/Main.java
/testing_package/Image.png

Now Here is a program to get Image.png and put it in database

public class Main {
    public static void main(String...args) {
        System.out.println(Main.class.getResource("image.jpg"));
        //PreparedStatement as ps
        ps.setBinaryStream(1, Main.class.getResourceAsStream("image.jpg")));
    }
}

Thing to keep in mind
When using getResource(...) or getResourceAsStream(...) use relative location to the class instance whose function you are invoking.

Have a look at this answer too