Can someone explain what is the difference between the following two calls to ServletContext getRealPath() in Tomcat:
context.getRealPath("/") + "\\songModified.wav";context.getRealPath("/" + "\\songModified.wav");
I have a very simple GET method on the server which reads a file on the server and copies the bytes into a new file in the location returned by the above call.
On the client side I have an audio tag that references an audio file on the server, calls this method that creates a new file and changes the reference of the audio tag to this new file. The thing is that in the javascript callback this new file is not immediately referenceable if I store the file to the path that is returned from the second case of the above getRealPath call. Basically it returns a 404. If I store it to the returned path of the first case of the call then it is immediately referenceable and the audio tag normaly references the new file.
Both of those calls to getRealPath() return exactly the same string:
C:\Users\Mihael\apache-tomcat-9.0.31\wtpwebapps\AudioSimulator\songModified.wav
I am passing this returned string to the FileOutputStream constructor further in the code.
Thing to note here is that this file does not exist at the moment of the getRealPath() call so I am confused why is it returning anything at all in the second case of the call.
I know this is not the recommended way of storing files so I am asking from a purely educational perspective. How can the second call to this method break my functionality if they both return exactly the same string to the rest of the code?
EDIT:
Here is a very simple Javascript and Java code for anyone who wants to test this.
Javascript:
<body>
<script>
function modifyRequest() {
var xhttp = new XMLHttpRequest();
xhttp.onload = function() {
var audio = document.getElementById("player");
var currentTime = audio.currentTime;
audio.src = "http://localhost:8080/AudioSimulator/bluesModified.wav";
audio.currentTime = currentTime;
audio.play();
};
xhttp.open("GET", "http://localhost:8080/AudioSimulator/rest/Test/testPath");
xhttp.send();
}
</script>
<audio id="player" src="http://localhost:8080/AudioSimulator/blues.wav"
controls>
Your browser does not support the
<code>audio</code> element.
</audio>
<button onclick="modifyRequest()">Test</button>
</body>
Java:
@Path("/Test")
public class Test {
@Context
ServletContext context;
@GET
@Path("/testPath")
public Response testPath() {
File fileIn = new File(context.getRealPath("/") + "\\blues.wav");
File fileOut = new File(context.getRealPath("/" + "\\bluesModified.wav"));
//if i write it like this it would work
//File fileOut = new File(context.getRealPath("/") + "\\bluesModified.wav");
FileInputStream fis = null;
FileOutputStream fos = null;
try {
fis = new FileInputStream(fileIn);
fos = new FileOutputStream(fileOut);
byte[] inArray = new byte[(int) fileIn.length()];
try {
fis.read(inArray);
fos.write(inArray);
} catch (IOException e) {
e.printStackTrace();
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} finally {
try {
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
fis.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return Response
.ok()
.entity("Success")
.header("Access-Control-Allow-Origin", "null")
.build();
}
}