TCP通讯过程中,由于网络原因或者其他原因,经常出现粘包和半包现象。所以在具体编程中需要考虑。
下边的 java 代码是用 NIO 实现的一个Server端,消息的通讯格式为:
4字节int类型 [包头] + 包体.
包头描述出包体的长度。
package com.sof.nio;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Set;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class Reactor implements Runnable
{
private static Logger logger = LoggerFactory.getLogger(Reactor.class);
final Selector selector;
final ServerSocketChannel serverSocket;
public Reactor(String ip, int port) throws IOException
{
selector = Selector.open();
serverSocket = ServerSocketChannel.open();
serverSocket.socket().bind(new InetSocketAddress(port));
serverSocket.configureBlocking(false);
SelectionKey sk = serverSocket.register(selector, SelectionKey.OP_ACCEPT);
sk.attach(new Acceptor());
}
public void run()
{
try
{
while (!Thread.interrupted())
{
logger.debug("selector is waitting event....");
selector.select();
Set<SelectionKey> keys = selector.selectedKeys();
if (keys.size() == 0)
{
logger.debug("nothing ha