使用java中nio包的socketChannel可以从客户端套接字获取的最大数据大小
使用使用java中nio包的socketChannel可以从客户端套接字获取的最大数据大小,java,Java,使用SocketChannel sc=(SocketChannel)key.channel(),我们可以将数据从端口提取到缓冲区。 为了在不丢失数据的情况下连续地从端口接收数据,代码应该是怎样的 这是我的密码 import java.io.*; import java.net.*; import java.nio.*; import java.nio.channels.*; import java.util.*; public class MultiPortEcho { private i
SocketChannel sc=(SocketChannel)key.channel()代码>,我们可以将数据从端口提取到缓冲区。
为了在不丢失数据的情况下连续地从端口接收数据,代码应该是怎样的
这是我的密码
import java.io.*;
import java.net.*;
import java.nio.*;
import java.nio.channels.*;
import java.util.*;
public class MultiPortEcho
{
private int ports[];
private ByteBuffer echoBuffer = ByteBuffer.allocate(32000);
public MultiPortEcho( int ports[] ) throws IOException
{
this.ports = ports;
go();
}
private void go() throws IOException
{
// Create a new selector
Selector selector = Selector.open();
// Open a listener on each port, and register each one
// with the selector
for (int i=0; i<ports.length; ++i)
{
ServerSocketChannel ssc = ServerSocketChannel.open();
ssc.configureBlocking( false );
ServerSocket ss = ssc.socket();
InetSocketAddress address = new InetSocketAddress( ports[i] );
ss.bind( address );
SelectionKey key = ssc.register( selector, SelectionKey.OP_ACCEPT );
System.out.println( "Going to listen on "+ports[i] );
}
while (true)
{
int num = selector.select();
System.out.println("num::::"+num);
Set selectedKeys = selector.selectedKeys();
Iterator it = selectedKeys.iterator();
while (it.hasNext())
{
SelectionKey key = (SelectionKey)it.next();
if ((key.readyOps() & SelectionKey.OP_ACCEPT)== SelectionKey.OP_ACCEPT)
{
// Accept the new connection
ServerSocketChannel ssc = (ServerSocketChannel)key.channel();
SocketChannel sc = ssc.accept();
sc.configureBlocking( false );
// Add the new connection to the selector
SelectionKey newKey = sc.register(selector,SelectionKey.OP_READ);
it.remove();
System.out.println( "Got connection from "+sc );
}
else if ((key.readyOps() & SelectionKey.OP_READ)== SelectionKey.OP_READ)
{
// Read the data
SocketChannel sc =(SocketChannel)key.channel();
System.out.println("sc::::"+sc);
// data to fetched from channel and dump into the datatbase
int bytesEchoed = 0;
//while(true)
{
echoBuffer.clear();
int r = sc.read(echoBuffer);
System.out.println("r:::" + r);
/*int pos=echoBuffer.position();
System.out.println("pos:::" +pos);*/
if (r == -1)
{
//echoBuffer.flip();
echoBuffer.rewind();
byte[] array = new byte[100000];
while (echoBuffer.hasRemaining())
{
int n = echoBuffer.remaining();
System.out.println("size:" + n);
echoBuffer.get(array,0,n );
System.out.println(new String(array,0,n));
key.cancel();
it.remove();
}
}
/*int pos=echoBuffer.position();
System.out.println("pos:::" + pos);
if(r<=0)
{
echoBuffer.flip();
for (int j = 0; j < pos; j++ )
{
String ss =Integer.toHexString(echoBuffer.get());
if (ss.length() == 1)
System.out.print("0" + ss + " ");
else if (ss.length() > 2)
System.out.print(ss.substring(6) + " ");
else System.out.print(ss + " ");
}
break;
}
echoBuffer.flip();
sc.write( echoBuffer );
bytesEchoed += r;*/
}
//System.out.println( "Echoed "+bytesEchoed+" from "+sc );
//it.remove();
}
}
//System.out.println( "going to clear" );
// selectedKeys.clear();
//System.out.println( "cleared" );
}
}
static public void main( String args[] ) throws Exception
{
FileOutputStream fileoutputstream = new FileOutputStream("MultiPort.txt", false);
PrintStream printstream = new PrintStream(fileoutputstream);
System.setOut(printstream);
if (args.length<=0) {
System.err.println( "Usage: java MultiPortEcho port [port port ...]" );
System.exit( 1 );
}
int ports[] = new int[args.length];
for (int i=0; i<args.length; ++i) {
ports[i] = Integer.parseInt( args[i] );
}
new MultiPortEcho( ports );
}
}
import java.io.*;
导入java.net。*;
导入java.nio.*;
导入java.nio.channels.*;
导入java.util.*;
公共类多端口
{
专用int端口[];
私有ByteBuffer echoBuffer=ByteBuffer.allocate(32000);
公共多端口CHO(点端口[])引发IOException
{
这个端口=端口;
go();
}
私有void go()引发IOException
{
//创建一个新的选择器
选择器=选择器。打开();
//在每个端口上打开一个侦听器,并注册每个端口
//用选择器
对于(int i=0;i您可以在这里找到一些线索,其中arereadFromChannel()
函数可能会让您感兴趣
public void readFromChannel() {
try {
[...]
if (readBuffer != null) {
readBuffer.flip();
receivingBroker.broker(readBuffer, false);
if (readBuffer != null) {
readBuffer.clear();
readBuffer = null;
}
}
if (readBuffer == null || !readBuffer.hasRemaining()) {
getThread().removeInterestOp(this, SelectionKey.OP_READ);
getThread().addInterestOp(this, SelectionKey.OP_WRITE);
}
if (receivingBroker.isClosed()) {
if (getChannelListener() != null) {
getChannelListener().readFinished(this);
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
对总体设计的评论:
编写网络服务器有两种基本方法。阻塞和非阻塞。2008年,我们的任务是用Python实现一个高性能的网络服务器。在尝试了两种不同的非阻塞方法后,我们发现它更容易使用:
- 阻塞插座
- 每个连接一个线程
- 几个管理器线程
这样,每个线程都可以坐在那里等待数据,直到它死的那一天,当它收到一个完整的数据包时,它就会对数据采取行动
仅供考虑。作为第一个修复,您应该删除带有key.cancel()的行。保留它将取消密钥,并确保在第一次读取后不会考虑密钥-这将有效地阻止您以后读取任何内容。当您使用NIO接受连接时,您可以获得套接字并设置相应的输入/输出缓冲区大小
socketChannel.socket().setReceiveBufferSize(512);
socketChannel.socket().setSendBufferSize(16);
由于NIO大量使用操作系统的网络堆栈,这只是一个提示。所有这些事实都在中有很好的记录。您可以读取的最大大小实际上受到您拥有的内存量的限制
但是,为了提高效率,您不需要读取超大数据块。您应该发现1MB已经足够了。事实上,您可能会发现4KB的数据块足够大,可以为1GB连接获得最大带宽。大多数操作系统都有缓冲区大小的最小大小,因此设置如此小的值不会达到您认为的效果。我建议gest尝试64*1024或更大。我这样做了,发现它也减少了延迟。(减少了线程之间的传递)