import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.util.CharsetUtil;
import lombok.extern.slf4j.Slf4j;
import java.io.IOException;
import java.net.InetSocketAddress;
/**
* I/O data read and write processing class
*
* @author xiaobo
*/
@Slf4j
public class CarTcpNettyChannelInboundHandlerAdapter extends ChannelInboundHandlerAdapter {
/**
* When new data is received from the client, this method will be called when the message is received.
*
* @param ctx
* @param msg
*/
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception, IOException {
// Here is the DelimiterBasedFrameDecoder in the previous section to be converted to ByteBuf to verify whether it is ByteBuf
if (msg instanceof ByteBuf) {
ByteBuf byteBuf = (ByteBuf) msg;
try {
String receivedData = byteBuf.toString(CharsetUtil.UTF_8);
// Receive complete data
handleReceivedData(receivedData);
} finally {
// Release resources occupied by ByteBuf
byteBuf.release();
// Reply to the message
ctx.writeAndFlush(Unpooled.copiedBuffer("Received over", CharsetUtil.UTF_8));
}
}
}
private void handleReceivedData(String receivedData) {
// Data processing
// If you want to implement bean injection in spring, you can use geBean to obtain it
}
/**
* Called when new data is received from the client and read is completed
*
* @param ctx
*/
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws IOException {
log.info("channelReadComplete");
ctx.flush();
}
/**
* When a Throwable object appears, it will be called, that is, when Netty is thrown due to an IO error or an exception thrown by the processor when processing an event
*
* @param ctx
* @param cause
*/
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws IOException {
cause.printStackTrace();
ctx.close();// Throw an exception and disconnect from the client
}
/**
* Execute when the client and the server establish a connection for the first time
*
* @param ctx
* @throws Exception
*/
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception, IOException {
super.channelActive(ctx);
ctx.channel().read();
InetSocketAddress socket = (InetSocketAddress) ctx.channel().remoteAddress();
String clientIp = socket.getAddress().getHostAddress();
// Cannot use() here, otherwise the client will never be able to establish a connection with the server
System.out.println("channelActive:" + clientIp + ctx.name());
// Here is a response to the client
ctx.writeAndFlush(Unpooled.copiedBuffer("Received over", CharsetUtil.UTF_8));
}
/**
* When the client and the server are disconnected, execute
*
* @param ctx
* @throws Exception
*/
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception, IOException {
super.channelInactive(ctx);
InetSocketAddress socket = (InetSocketAddress) ctx.channel().remoteAddress();
String clientIp = socket.getAddress().getHostAddress();
// When disconnecting, it must be closed, otherwise it will cause waste of resources and may cause downtime if the concurrency is large.
ctx.close();
log.info("channelInactive:{}", clientIp);
}
/**
* When the read timeouts on the server, this method will be called
*
* @param ctx
* @param evt
* @throws Exception
*/
@Override
public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception, IOException {
super.userEventTriggered(ctx, evt);
InetSocketAddress socket = (InetSocketAddress) ctx.channel().remoteAddress();
String clientIp = socket.getAddress().getHostAddress();
ctx.close();// Disconnect when timeout
log.info("userEventTriggered:" + clientIp);
}
@Override
public void channelRegistered(ChannelHandlerContext ctx) throws Exception {
log.info("channelRegistered");
}
@Override
public void channelUnregistered(ChannelHandlerContext ctx) throws Exception {
log.info("channelUnregistered");
}
@Override
public void channelWritabilityChanged(ChannelHandlerContext ctx) throws Exception {
log.info("channelWritabilityChanged");
}
}
