目录
1 DelimiterBasedFrameDecoder应用开发
1.1 DelimiterBasedFrameDecoder服务端开发
1.3 运行DelimiterBasedFrameDecoder服务端和客户端
2.1 FixedLengthFrameDecoder服务端开发
2.2 利用telnet命令行测试EchoServer服务端
分隔符和定长解码器的应用
案例：回声测试（客户端发送什么请求数据，服务端返回什么数据）
1 DelimiterBasedFrameDecoder应用开发
1.1 DelimiterBasedFrameDecoder服务端开发
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
public void initChannel(SocketChannel ch) throws Exception {
ByteBuf delimiter = Unpooled.copiedBuffer("$_".getBytes());
ch.pipeline().addLast(new DelimiterBasedFrameDecoder(1024, delimiter));
ch.pipeline().addLast(new StringDecoder());
ch.pipeline().addLast(new EchoServerHandler());
}
});
// 绑定端口，同步等待成功
ChannelFuture f = b.bind(port).sync();
// 等待服务端监听端口关闭
f.channel().closeFuture().sync();
} finally {
// 优雅退出，释放线程池资源
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
public static void main(String[] args) throws Exception {
int port = 8080;
if (args != null && args.length > 0) {
try {
port = Integer.valueOf(args[0]);
} catch (NumberFormatException e) {
// 采用默认值
}
}
new EchoServer().bind(port);
}
}@Sharable
public class EchoServerHandler extends ChannelHandlerAdapter {
int counter = 0;
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
String body = (String) msg;
System.out.println("This is " + ++counter + " times receive client : [" + body + "]");
body += "$_";
ByteBuf echo = Unpooled.copiedBuffer(body.getBytes());
ctx.writeAndFlush(echo);
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
cause.printStackTrace();
ctx.close();// 发生异常，关闭链路
}
}
1.2 DelimiterBasedFrameDecoder客户端开发
public class EchoClient {
public void connect(int port, String host) 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
public void initChannel(SocketChannel ch) throws Exception {
ByteBuf delimiter = Unpooled.copiedBuffer("$_".getBytes());
ch.pipeline().addLast(new DelimiterBasedFrameDecoder(1024, delimiter));
ch.pipeline().addLast(new StringDecoder());
ch.pipeline().addLast(new EchoClientHandler());
}
});
// 发起异步连接操作
ChannelFuture f = b.connect(host, port).sync();
// 当代客户端链路关闭
f.channel().closeFuture().sync();
} finally {
// 优雅退出，释放NIO线程组
group.shutdownGracefully();
}
}
/**
* @param args
* @throws Exception
*/
public static void main(String[] args) throws Exception {
int port = 8080;
if (args != null && args.length > 0) {
try {
port = Integer.valueOf(args[0]);
} catch (NumberFormatException e) {
// 采用默认值
}
}
new EchoClient().connect(port, "127.0.0.1");
}
}public class EchoClientHandler extends ChannelHandlerAdapter {
private int counter;
static final String ECHO_REQ = "Hi, Lilinfeng. Welcome to Netty.$_";
/**
* Creates a client-side handler.
*/
public EchoClientHandler() {
}
@Override
public void channelActive(ChannelHandlerContext ctx) {
// ByteBuf buf = UnpooledByteBufAllocator.DEFAULT.buffer(ECHO_REQ
// .getBytes().length);
// buf.writeBytes(ECHO_REQ.getBytes());
for (int i = 0; i < 10; i++) {
ctx.writeAndFlush(Unpooled.copiedBuffer(ECHO_REQ.getBytes()));
}
}
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
System.out.println("This is " + ++counter + " times receive server : [" + msg + "]");
}
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
ctx.flush();
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
cause.printStackTrace();
ctx.close();
}
}
1.3 运行DelimiterBasedFrameDecoder服务端和客户端
This is 1 times receive client : [Hi, Lilinfeng. Welcome to Netty.]
This is 2 times receive client : [Hi, Lilinfeng. Welcome to Netty.]
This is 3 times receive client : [Hi, Lilinfeng. Welcome to Netty.]
This is 4 times receive client : [Hi, Lilinfeng. Welcome to Netty.]
This is 5 times receive client : [Hi, Lilinfeng. Welcome to Netty.]
This is 6 times receive client : [Hi, Lilinfeng. Welcome to Netty.]
This is 7 times receive client : [Hi, Lilinfeng. Welcome to Netty.]
This is 8 times receive client : [Hi, Lilinfeng. Welcome to Netty.]
This is 9 times receive client : [Hi, Lilinfeng. Welcome to Netty.]
This is 10 times receive client : [Hi, Lilinfeng. Welcome to Netty.]
核心点是在服务端的和客户端的pipeline中添加自定义分隔符的解码器DelimiterBasedFrameDecoder
ByteBuf delimiter = Unpooled.copiedBuffer("$_".getBytes());
ch.pipeline().addLast(new DelimiterBasedFrameDecoder(1024, delimiter));
2 FixedLengthFrameDecoder应用开发
核心点在server端的pipeline添加FixedLengthFrameDecoder
ch.pipeline().addLast(new FixedLengthFrameDecoder(20));
2.1 FixedLengthFrameDecoder服务端开发
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
public void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast(new FixedLengthFrameDecoder(20));
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();
} finally {
// 优雅退出，释放线程池资源
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
public static void main(String[] args) throws Exception {
int port = 8080;
if (args != null && args.length > 0) {
try {
port = Integer.valueOf(args[0]);
} catch (NumberFormatException e) {
// 采用默认值
}
}
new EchoServer().bind(port);
}
}@Sharable
public class EchoServerHandler extends ChannelHandlerAdapter {
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
System.out.println("Receive client : [" + msg + "]");
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
cause.printStackTrace();
ctx.close();// 发生异常，关闭链路
}
