Exception while reading data from server.

[ajitkumar26]

Hi All I amm getting exception while reading data from the server.

Following is the code I have written to read data from server.

private String readServerData(InputStream inputStream) throws IOException {
StringBuffer strBuf = new StringBuffer();
int length = (int) httpConnection.getLength();
byte incomingData[] = null;
if (length != -1) {
incomingData = new byte[2048];
while ((length = inputStream.read(incomingData)) != -1) {
strBuf.append(new String(incomingData, 0, length, "UTF-8"));
}
dataBuffer = strBuf.toString();
} else {
ByteArrayOutputStream byteStream =
new ByteArrayOutputStream();
int ch;
//reading the stream byte by byte to prevent the
//loss of data that is sometimes observed on reading all at once.
while ((ch = inputStream.read()) != -1) {
byteStream.write(ch);
}
dataBuffer = new String(byteStream.toByteArray(), "UTF-8");
byteStream.close();
}
inputStream = null;
strBuf = null;
incomingData = null;
return dataBuffer;
}

The above code is working fine with Nokia 3110C and Nokia 2700c devices while the Exception is occuring in C5-00 though the data is same for all.

Please help me to resolve this issue.


Thanks & Regards,
Ajit

[skalogir]

I have tested your code in order to fetch the contents of a page on C5, on a software version released on 11th December 2010 and I didn't have any problems.

This is what I tried

import java.io.ByteArrayOutputStream;
import java.io.InputStream;

import javax.microedition.io.Connector;
import javax.microedition.io.HttpConnection;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Form;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;



public class Temp extends MIDlet {
	Form f;
	HttpConnection httpConnection;
	StringBuffer strBuf;
	String dataBuffer;
	public Temp() {
		// TODO Auto-generated constructor stub
	}

	protected void destroyApp(boolean arg0) throws MIDletStateChangeException {
		// TODO Auto-generated method stub

	}
	protected String readServerData() {
		try{
			httpConnection = (HttpConnection) Connector.open("http://www.google.com");
			InputStream inputStream=httpConnection.openInputStream();
			strBuf = new StringBuffer();
			int length = (int) httpConnection.getLength();
			byte incomingData[] = null;
			if (length != -1) {
				incomingData = new byte[2048];
				while ((length = inputStream.read(incomingData)) != -1) {
					strBuf.append(new String(incomingData, 0, length, "UTF-8"));
				}
				dataBuffer = strBuf.toString();
			} else 
			{
				ByteArrayOutputStream byteStream =
					new ByteArrayOutputStream();
				int ch;
				//reading the stream byte by byte to prevent the
				//loss of data that is sometimes observed on reading all at once.
				while ((ch = inputStream.read()) != -1) {
					byteStream.write(ch);
				}
				dataBuffer = new String(byteStream.toByteArray(), "UTF-8");
				byteStream.close();
			}
			inputStream = null;
			strBuf = null;
			incomingData = null;
			return dataBuffer;
		}catch(Exception e){return null;}
	}
	
	protected void pauseApp() {
		// TODO Auto-generated method stub

	}

	protected void startApp() throws MIDletStateChangeException {
		String output;
		output=readServerData();
		f=new Form("");
		f.append(output);
		Display.getDisplay(this).setCurrent(f);
		
	}

}

Can you try the full example as I post it here? Can you get the message of the Exception? You can see what software version you are testing on by pressing *#0000# and update your device's software, if necessary.

[ajitkumar26]

Actually the Runtime IOException is occurring when there is Chinese text coming from the server.
With english text it is working fine.
I am trying with around 75 KB of data which is a combination of both English and Chinese text.

Please find the device software details as follows:

The software version is - 062.001
SW version date- 11-Dec-2010
Custom version- 062.001.c00.01
Custom version date-11-Dec-2010
Language set- 21.01
Model- C5-00
Type- RM-645
Latest update- Not updated

What could be the root cause? Please help me...

Thanks & Regards,
Ajit

[skalogir]

It's a character encoding issue. I can retrieve data, when I replace all instances of the String initialization

new String(byteStream.toByteArray(), "UTF-8");

with this

new String(byteStream.toByteArray());

I have tested the code with information from this page:
http://zhengwu.beijing.gov.cn/bmfu/bmts/t1202056.htm

You might need to handle the information you are retrieving according to the page's character encoding standard.
For more information on chinese character encoding:
http://en.wikipedia.org/wiki/Chinese_character_encoding

You can see the character encoding of the page you are trying to retrieve in Windows 7 and Firefox by right clicking on the page, and selecting "View Page Source". In the page's source, you should see something like this:

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />

[ajitkumar26]

Thanks for your response.
Which of the following line of code is correct (1) or (2)
1. new String(byteStream.toByteArray(), "UTF-8");
2.new String(byteStream.toByteArray());

And one more thing is that the data are not only chinese or english it's a combination of both. So UTF-8 should work fine.
Please help me...

Thanks & Regards,
Ajit

[skalogir]

No 2 is the code that can retrieve data from a chinese web site on your C5 device. No1 is what you provided on the code sample you posted here.

[ajitkumar26]

Server is sending data in UTF-8 encoding format so I am using UTF-8 only
In which encoding for both the chinese and english data can be encoded?


Thanks & Regards,
Ajit

[skalogir]

Have you modified the code, according to my previous post? If so, what is the result? Can you retrieve data, or do you still get the exception error? If the problem still insists, can you provide the page link?

[ajitkumar26]

No after changing with the cde it is working fine but while displaying sometime it might come as a junk character while displaying on the String if I will not give any encoding format. Isn't it?


Thanks & regards,
Ajit

[skalogir]

Hi Ajit,

UTF-8 should work fine when a combination of Chinese and English is used in a page. You should use the same encoding as the encoding the server you are retrieving from, is using. Provided that you are retrieving data from a UTF-8 encoded page, your original code without any modifications, should work fine (i.e. the code you provided on your first post in this thread). I have tested your code, in an effort to retrieve data from this page:
http://www.columbia.edu/~fdc/utf8/
which is written in a combination of Chinese, English and other non-latin languages and is encoded in UTF-8.
Your code works fine on C5-00. I cannot reproduce your error.