标签：his OLE echo led cti contex exception log extends
分隔符和定长解码器
1、消息长度固定，累计读取到长度总和为定长LEN的报文后，就认为读取到了一个完整的消息；将计数置位，重新开始读取下一个数据报。
2、将回车换行符作为消息结束符，例如FTP协议，这种方式在文本协议中应用比较广泛
3、将特殊的分隔符作为消息的结束标志，回车换行符就是一种特殊的结束分隔符
4、通过在消息头中定义长度字段来标识消息的总长度。
DelimiterBasedFrameDecoder：可以自动完成以分隔符结束标志的消息的解码，
服务端
public class EchoServer {
public void bind(int port) throws Exception{
//配置服务端的NIO线程组
EventLoopGroup bossGroup = new NioEventLoopGroup();
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap b = new ServerBootstrap();
b.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.option(ChannelOption.SO_BACKLOG, 100)
.handler(new LoggingHandler(LogLevel.INFO))
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
//自定义特殊符号,以"$_"为结束符
ByteBuf delimiter = Unpooled.copiedBuffer("$_".getBytes());
ch.pipeline().addLast(new DelimiterBasedFrameDecoder(1024,delimiter));
ch.pipeline().addLast(new StringDecoder());
ch.pipeline().addLast(new EchoServerHandler());
}
});
//绑定端口，同步等待成功
ChannelFuture f = b.bind(port).sync();
//等待服务端监听端口关闭
f.channel().closeFuture().sync();
} catch (Exception e) {
}finally {
//释放资源
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
public static void main(String[] args) throws Exception {
int port = 8088;
new EchoServer().bind(port);
}
}
服务端处理类
public class EchoServerHandler extends ChannelHandlerAdapter {
private int counter;
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
//获取客户端消息(msg就是客户端发过来的消息)
String body = (String)msg;
System.out.println("This is "+ (++counter) +
" times receive client:" + "[" +body + "]");
body = body + "$_";
ByteBuf echo = Unpooled.copiedBuffer(body.getBytes());
//向客户端发送消息
System.out.println("准备发送");
//Thread.sleep(5000);
ctx.writeAndFlush(echo);
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
ctx.close();//发生异常，关闭链路
}
}
客户端
public class EchoClient {
public void connect(String host,int port) throws Exception{
//配置客户端NIO线程组
EventLoopGroup group = new NioEventLoopGroup();
try {
Bootstrap b = new Bootstrap();
b.group(group).channel(NioSocketChannel.class)
.option(ChannelOption.TCP_NODELAY, true)
.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ByteBuf delimiter = Unpooled.copiedBuffer("$_".getBytes());
ch.pipeline().addLast(new DelimiterBasedFrameDecoder(1024,delimiter));
ch.pipeline().addLast(new StringDecoder());
ch.pipeline().addLast(new EchoClientHandler());
}
});
//发起异步连接操作
ChannelFuture f = b.connect(host,port);
//等待客户端链路关闭
f.channel().closeFuture().sync();
} finally {
//释放NIO线程组
group.shutdownGracefully();
}
}
public static void main(String[] args) throws Exception {
String host = "localhost";
int port = 8088;
new EchoClient().connect(host, port);
}
}
客户端处理类
public class EchoClientHandler extends ChannelHandlerAdapter {
private int counter;
static final String ECHO_REQ = "Hi,Lilinfeng. welcome to Netty.$_";
public EchoClientHandler(){
}
public void channelActive(ChannelHandlerContext ctx) throws Exception {
for(int i = 0 ;i < 10 ; i++){
//向服务端发送信息
ctx.writeAndFlush(Unpooled.copiedBuffer(ECHO_REQ.getBytes()));
}
}
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
//打印从服务端接收的消息
System.out.println("This is " + (++counter) +
" times receive server:[" + msg + "]");
}
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
ctx.flush();
}
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
ctx.close();
}
}
标签：his OLE echo led cti contex exception log extends
原文地址：https://www.cnblogs.com/lazyli/p/10816882.html
