String to CharBuffer
Hi @all i'm new in the world of Java,
but i have a problem to convert a String into CharBuffer. I wrote a programm that send info over network using Sockets. To send is no problem but to read, i became the message that i have to convert String into CharBuffer. I really don't know if it is possible. Thank you for the help.
The code is:
import java.net.*;
import java.io.*;
import java.nio.CharBuffer;
public class ADatenClient {
public static void main(String args[]){
Socket server = null;
int BallX;
int BallY;
int SchlgX;
int SchlgY;
BallX = balla.getBall_x_pos();
BallY = balla.getBall_y_pos();
Schlaeger Schl2 = new Schlaeger;
SchlgX = Schl2.getSchl_x_pos();
SchlgY = Schl2.getSchl_y_pos();
try{
server = new Socket("localhost", 50000);
InputStream in = server.getInputStream();
OutputStream out = server.getOutputStream();
OutputStreamWriter out1 = new OutputStreamWriter(out);
OutputStreamWriter out2 = new OutputStreamWriter(out);
OutputStreamWriter out3 = new OutputStreamWriter(out);
OutputStreamWriter out4 = new OutputStreamWriter(out);
out1.write("<ballx>"+Integer.toString(BallX)+"</ballx>");
out2.write("<bally>"+Integer.toString(BallY)+"</bally>");
out3.write("<schlaegerx>"+Integer.toString(SchlgX)+"</schlaegerx>");
out4.write("<schlaegery>"+Integer.toString(SchlgY)+"</schlaegery>");
InputStreamReader in1 = new InputStreamReader(in);
InputStreamReader in2 = new InputStreamReader(in);
InputStreamReader in3 = new InputStreamReader(in);
InputStreamReader in4 = new InputStreamReader(in);
/*in1.read("<ballx>"+CharBuffer.wrap(BallX)+"</ballx>");
in2.read("<bally>"+CharBuffer.wrap(BallY)+"</bally>");
in3.read("<schlaegerx>"+CharBuffer.wrap(SchlgX)+"</schaegerx>");
in4.read("<schlaegery>"+CharBuffer.wrap(SchlgY)+"</schaegery>");
}catch(UnknownHostException e){
e.printStackTrace();
}catch(IOException e){
e.printStackTrace();
finally{
if(server != null)
try{
server.close();
} catch(IOException e){
e.printStackTrace();
}
Thank for answer.
I put it so:
CharBuffer BalX;
in1.read("<ballx>"+BalX.wrap(String.valueOf(BallX).toC
harArray() +"</ballx>");
And Eclipse says : The method read(CharBuffer) in the
type Reader is not applicable for the arguments
(String)
I have no idea, what can i do.
Thank you!what about:
in1.read(BalX.wrap(("<ballx>" + BallX + "</ballx>").toCharArray() );but heck, I'm no expert in this area...
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NIO Non-Blocking Server not Reading from Key
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package jamb.server;
import java.io.IOException;
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import java.net.InetSocketAddress;
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Hello Techies,
How to set sockets in the non-blocking mode and what is the main use of setting sockets in non-blocking mode.
regards,
Ramu.Hello Techies,
Thanks for u r replies,
Finally i had understood how to use nio. But the problem is it is going into infinite loop. Here is my code.
package networking;
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* @param args
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Here is an example...
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at HagerAbs.setEditFragment(HagerAbs.java:91)
at HagerAbs.main(HagerAbs.java:108)When i write my input to the xml file it doesnt look like xml at all, it looks more like
<synthese>& # 13;
& # 13;
& lt;br/& gt;& # 13;
& lt;img class="thumb" src="http: ......{code}
(i seperated the char so you can see)
and this is not what i expected... how can i write it down correctly ?
Edited by: Sephiknight on Feb 23, 2008 3:26 AM -
CharBuffer view on ByteBuffer and No Bytes Written to SocketChannel
Hi,
I've actually got two problems that might be connected. I'm new to the java.nio.* package. I wanted to try SocketChannel's to see if I could improve performance.
If this isn't the appropriate place for java.nio questions, just let me know.
My first problem is that I create a ByteBuffer by allocating x number of bytes. These bytes are the length of the message I want to send to the server. Then, I attempt to get a CharBuffer view of the ByteBuffer (buffer.asCharBuffer). For some reason, it only returns a CharBuffer with half the capacity of the ByteBuffer. So of course, when I stuff my String into the CharBuffer, it doesn't fit.
Well, I hack that and make the ByteBuffer twice as big. Which brings me to problem two, my SocketChannel does not write any bytes to the server when told to.
Here's the code (with hack):
ByteBuffer buf;
CharBuffer cbuf;
SocketChannel sockChan;
try {
int msgLength = message.length();
logger.info("Message length=" + msgLength);
logger.info("message length in bytes=" + message.getBytes().length);
buf = ByteBuffer.allocateDirect(msgLength*2);
logger.info("position=" + buf.position());
logger.info("capacity=" + buf.capacity());
logger.info("limit=" + buf.limit());
cbuf = buf.asCharBuffer();
logger.info("capacity of cbuf=" + cbuf.capacity());
cbuf.put(message);
buf.flip();
sockChan = SocketChannel.open();
sockChan.configureBlocking(true);
sockChan.socket().setSoTimeout(TIMEOUT_MS);
logger.info("socket configured");
sockChan.connect(new InetSocketAddress(ipAddress, portNumber));
int numBytesWritten = sockChan.write(buf);
logger.info("connected and wrote message. NumBytes writen=" + numBytesWritten);
if (numBytesWritten != msgLength) {
//throw error
logger.error("The number of bytes written do not match the " +
"message length (in bytes).");
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}And the console outputs the following:
[Dec 13, 11:46:17] INFO - Message length=50
[Dec 13, 11:46:17] INFO - message length in bytes=50
[Dec 13, 11:46:17] INFO - position=0
[Dec 13, 11:46:17] INFO - capacity=100
[Dec 13, 11:46:17] INFO - limit=100
[Dec 13, 11:46:17] INFO - capacity of cbuf=50
[Dec 13, 11:46:17] INFO - socket configured
[Dec 13, 11:46:17] INFO - connected and wrote message. NumBytes writen=0
[Dec 13, 11:46:17] ERROR - The number of bytes written do not match the message length (in bytes).My batch program freezes at this point. Don't know why it does that either.
Thanks for any help,
CowKingByteBuffer (buffer.asCharBuffer). For some reason, it
only returns a CharBuffer with half the capacity of
the ByteBuffer.The reason is simply that chars are twice as big as bytes, so you can only get half as many of them into the same space. The capacity of a ByteBuffer is measured in bytes. The capacity of a CharBuffer is measured in chars. The capacity of a DoubleBuffer is measured in doubles.
Well, I hack that and make the ByteBuffer twice as
big. Which brings me to problem two, my SocketChannel
does not write any bytes to the server when told to.As it says in the Javadoc for ByteBuffer, a view buffer has its own position, limit, and mark. When you put data into it the data goes 'through' into the underlying ByteBuffer but the revised position/limit do not. You have to do that yourself manually, remembering to multiply by two as above to account for the difference widths of chars and bytes. -
How to avoid string copy when spliting the string?
Hi all,
I have some old APIs (which I do not have control over) that expects the caller to pass the "content" of a text file as either String or String[] (each element is a line in the text file). Since the text file can be huge, I want to save memory and try to only hold 1 copy of the file content in memory. So, the question boils down to how can I make a String variable and a String[] variable share one single piece of memory.
After digging into the source code, I notice the String.substring(...) always makes allocate a new memory space for the returning string if the result substring is smaller than 1/4 of the actual String. The String.split() method internally also invokes the String.substring(...) method.
This creates a problem for me. If I first load the content of a file into a String "a". Then I call "String[] array = a.split("\n")", as the result, each element in the resulting array will be a copy of the substring of the original String "a" (since each line in my text file will be smaller than 1/4 of the entire file). StringTokenizer seems to have the same problem. Is there anything else I could do?
I really would like to extends the String class and override the substring method to make it always "share" the same memory content. But since String class is declared as final, I cannot do this. I think maybe the String.split() method implementation should make the return String[] from the split function share the same memory space as the original string. Any workaround anyone can suggest?
Thanks
-- GaryWhile you could try to create some sort of custom class, if you want something that is already in java, you need to use one of the instantiations of CharSequence
http://java.sun.com/j2se/1.5.0/docs/api/java/lang/CharSequence.html
Personally, I would recommend CharBuffer. From the look of it, it seems most like what you want.
Hi all,
I have some old APIs (which I do not have control
rol over) that expects the caller to pass the
"content" of a text file as either String or String[]
(each element is a line in the text file). Since the
text file can be huge, I want to save memory and try
to only hold 1 copy of the file content in memory.
So, the question boils down to how can I make a
a String variable and a String[] variable share one
single piece of memory.
After digging into the source code, I notice the
the String.substring(...) always makes allocate a new
memory space for the returning string if the result
substring is smaller than 1/4 of the actual String.
The String.split() method internally also invokes
s the String.substring(...) method.
This creates a problem for me. If I first load
oad the content of a file into a String "a". Then I
call "String[] array = a.split("\n")", as the result,
each element in the resulting array will be a copy of
the substring of the original String "a" (since each
line in my text file will be smaller than 1/4 of the
entire file). StringTokenizer seems to have the same
problem. Is there anything else I could do?
I really would like to extends the String class and
nd override the substring method to make it always
"share" the same memory content. But since String
class is declared as final, I cannot do this. I
think maybe the String.split() method implementation
should make the return String[] from the split
function share the same memory space as the original
string. Any workaround anyone can suggest?
Thanks
-- Gary -
Non-Blocking Writing and Strings
Hello.
My question is simple, is it possible to write strings using a non-blocking method?
I was praying that there was a method in the NIO API that allowed me to, yet i can't find one.
If the answer is blatantly obvious please forgive me, i'm tired and hungry :)
Thank you for looking at this topicStrings are written to files or sockets using a certain encoding. I usually use UTF-8, but your application might be different.
1. Get the SocketChannel from your non-blocking socket.
SocketChannel ch = mySocket.getChannel(); // mySocket is java.net.Socket2. Make a CharBuffer out of the String you want to send.
CharBuffer chars = CharBuffer.wrap(myString); // myString is your data3. Encode it so it becomes a ByteBuffer. I'll use the [UTF-8|http://www.joelonsoftware.com/articles/Unicode.html] Charset here.
ByteBuffer bytes = Charset.forName("UTF-8").encode(chars);4. Use the write(ByteBuffer) method in the SocketChannel from 1.
ch.write(bytes);Import declarations:
import java.nio.channels.SocketChannel;
import java.nio.CharBuffer;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;s -
Cannot assign an empty string to a parameter with JDBC type VARCHAR
Hi,
I am seeing the aforementioned error in the logs. I am guessing its happening whenever I am starting an agent instance in PCo. Can somebody explain whats going on?
Regards,
Chanti.
Heres the complete detail from logs -
Log Record Details
Message: Unable to retreive path for , com.sap.sql.log.OpenSQLException: Failed to set the parameter 1 of the statement >>SELECT ID, PARENTID, FULLPATH, CREATED, CREATEDBY, MODIFIED, MODIFIEDBY, REMOTEPATH, CHECKEDOUTBY FROM XMII_PATHS WHERE FULLPATH = ? <<: Cannot assign an empty string to a parameter with JDBC type >>VARCHAR<<.
Date: 2010-03-12
Time: 11:32:37:435
Category: com.sap.xmii.system.FileManager
Location: com.sap.xmii.system.FileManager
Application: sap.com/xappsxmiiearSounds like a UI browsing bug (when no path is selected from a catalog tree folder browser) - I would suggest logging a support ticket so that it can be addressed.
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