Java socket read bytes from C#

Question

I am trying to read a byte[] in my Java application sent from a C# application.

However, when I encode the string to byte[] in C# and reads it in Java, using the code below, I get all the characters but the last. Why is that?

Java receiving code:

int data = streamFromClient.read();
while(data != -1){
    char theChar = (char) data;
    data = streamFromClient.read();
    System.out.println("" + theChar);
}

C# sending code:

public void WriteMessage(string msg){

    byte[] msgBuffer = Encoding.Default.GetBytes(msg);
    sck.Send(msgBuffer, 0, msgBuffer.Length, 0);
}

My guess is you are not sending the last character.

Peter Lawrey
– Peter Lawrey

2014-02-13 14:46:53 +00:00
Commented Feb 13, 2014 at 14:46 — Peter Lawrey
– Peter Lawrey, Commented Feb 13, 2014 at 14:46
^yes lol. Can we see your sending code?

washcloth
– washcloth

2014-02-13 14:47:45 +00:00
Commented Feb 13, 2014 at 14:47 — washcloth
– washcloth, Commented Feb 13, 2014 at 14:47
I added the C# code to the post

Patrick Reck
– Patrick Reck

2014-02-13 15:08:11 +00:00
Commented Feb 13, 2014 at 15:08 — Patrick Reck
– Patrick Reck, Commented Feb 13, 2014 at 15:08

user432 · Accepted Answer · 2014-02-13 15:41:58Z

2

While others already have provided a possible solution, i want to show how i would solve this.

int data;
while((data=streamFromClient.read()) != -1) {
  char theChar = (char) data;
  System.out.println("" + theChar);
}

I just feel like this approach would be a little more clear. Feel free to choose which you like better.

To clarify: There is an error in your receiving code. You read the last byte but you never process it. On every iteration you print out the value of the byte received in the previous iteration. So the last byte would be processed when data is -1 but you don't enter the loop so it isn't printed.

edited Feb 13, 2014 at 15:41

answered Feb 13, 2014 at 15:08

user432

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1 Comment

C4stor Over a year ago

There is no need to initialize "data" to -1.

Sudhakar Tillapudi · Accepted Answer · 2014-02-13 15:41:26Z

1

You need to read the data untill unless it is becomes -1. so you need to move the reading statement inside infinite loop i.e. while(true) and comeout from it once if the result is -1.

Try This:

 int data = -1;
 while(true){
 data=streamFromClient.read();
 if(data==-1)
 {     
    break;
 }
 char theChar = (char) data;     
 System.out.println("" + theChar);
 }

edited Feb 13, 2014 at 15:41

answered Feb 13, 2014 at 14:51

Sudhakar Tillapudi

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2 Comments

C4stor Over a year ago

You call read() twice in the while loop, which is invalid I think. You'll miss half the characters.

Sudhakar Tillapudi Over a year ago

@C4stor: that is mistake, i forgot to remove that after copying actual code from OP's post, thank you

M7Jacks · Accepted Answer · 2014-02-13 14:54:19Z

-2

I thought that your while loop might have been off by 1 iteration somehow but it seems to me that your C# program is simply not sending all the characters.

answered Feb 13, 2014 at 14:54

M7Jacks

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1 Comment

M7Jacks Over a year ago

I'm not sure why I have received a down vote or why the accepted solution is "accepted". Yes, it prints the value from the previous iteration each time through the loop but when data is -1 in the previous iteration that means there is no more to process. Therefore there is no reason to go through the loop again.

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