Netty客户端使用以及重连
1. pom依赖
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
<version>4.1.30.Final</version>
</dependency>
2. 测试工具
链接:https://pan.baidu.com/s/1g64RpTcPwIgVFybcOFEJVA
提取码:ncz9
3. 代码实现
public class NettyClientUtil {
static String[] ips = {"127.0.0.1"};
static Integer port = 8886;
static Bootstrap bootstrap;
// 客户端就只需要创建一个 线程组了
static EventLoopGroup loopGroup = new NioEventLoopGroup();
public static void main(String[] args) {
for (String ip : ips) {
start(ip, port);
}
}
public static void start(String ip, Integer port) {
// 创建 启动器
bootstrap = new Bootstrap();
try {
bootstrap.group(loopGroup)
.channel(NioSocketChannel.class)
.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
socketChannel.pipeline().addLast(new IdleStateHandler(30, 0, 0, TimeUnit.SECONDS))
// .addLast(new FixedLengthFrameDecoder(22)) //数据包的长度
.addLast(new NettyClientHandler());
}
});
// 连接服务
ChannelFuture future = connect(ip, port);
// 对服务关闭 监听
// future.channel().closeFuture().sync();
} catch (Exception e) {
loopGroup.shutdownGracefully();
System.out.println(e.getMessage());
} /*finally {
}*/
}
public static ChannelFuture connect(String ip, Integer port) {
bootstrap.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 3000);
ChannelFuture channelFuture = bootstrap.connect(ip, port).addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) throws Exception {
if (!future.isSuccess()) {
System.out.println(Thread.currentThread().getName() + ">>>>>连接" + ip + ":" + port + "服务端超时,1秒后重试……");
Thread.sleep(1000);
connect(ip, port);
}
}
});
return channelFuture;
}
}
public class NettyClientHandler extends ChannelInboundHandlerAdapter {
/**
* 连接上服务的回调方法
*
* @param ctx
* @throws Exception
*/
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
InetSocketAddress inetSocketAddress = (InetSocketAddress) ctx.channel().remoteAddress();
// 发送数据
System.out.println(Thread.currentThread().getName() + ">>>>>连接上了" +
inetSocketAddress.getAddress().getHostAddress() + ":" + inetSocketAddress.getPort() + "服务端....");
}
/**
* 读取服务端返回的信息
*
* @param ctx
* @param msg
* @throws Exception
*/
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
ByteBuf buf = (ByteBuf) msg;
System.out.println(Thread.currentThread().getName() + ">>>>>" + buf.toString(CharsetUtil.UTF_8));
}
/**
* 异常断开回调方法
*
* @param ctx
* @throws Exception
*/
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
InetSocketAddress inetSocketAddress = (InetSocketAddress) ctx.channel().remoteAddress();
String ip = inetSocketAddress.getAddress().getHostAddress();
int port = inetSocketAddress.getPort();
System.out.println(Thread.currentThread().getName() + ">>>>>与服务端" +
ip + ":" + port + "断开连接,3秒后尝试重试连接……");
Thread.sleep(3000);
NettyClientUtil.connect(ip, port);
super.channelInactive(ctx);
}
}
4. 结果展示
连接服务端
服务端推送消息
关闭服务端
再次打开服务端