simplest possible POJO echo with netty

问题

How do I initiate an infinite loop between the client and server, to send and receive POJO PingPong objects between the client and server?

When a connection is established, which seems to be happening, the client should send a PingPong, and the server should reply with a PingPong POJO as well. The client should (preferably) respond with another PingPong, creating an infinite loop.

the server receives an object:

BUILD SUCCESSFUL
Total time: 2 seconds
Jul 20, 2014 2:43:17 PM io.netty.handler.logging.LoggingHandler channelRegistered
INFO: [id: 0x2cd55a8d] REGISTERED
Jul 20, 2014 2:43:17 PM io.netty.handler.logging.LoggingHandler bind
INFO: [id: 0x2cd55a8d] BIND(0.0.0.0/0.0.0.0:4454)
Jul 20, 2014 2:43:17 PM io.netty.handler.logging.LoggingHandler channelActive
INFO: [id: 0x2cd55a8d, /0:0:0:0:0:0:0:0:4454] ACTIVE
Jul 20, 2014 2:43:24 PM io.netty.handler.logging.LoggingHandler logMessage
INFO: [id: 0x2cd55a8d, /0:0:0:0:0:0:0:0:4454] RECEIVED: [id: 0xe7c06459, /127.0.0.1:33182 => /127.0.0.1:4454]
^Cthufir@dur:~/NetBeansProjects/NettyServer$ 
thufir@dur:~/NetBeansProjects/NettyServer$ 

which was sent by the client:

BUILD SUCCESSFUL
Total time: 2 seconds
Jul 20, 2014 2:43:24 PM io.netty.handler.logging.LoggingHandler channelRegistered
INFO: [id: 0x0f1fc251] REGISTERED
Jul 20, 2014 2:43:24 PM io.netty.handler.logging.LoggingHandler connect
INFO: [id: 0x0f1fc251] CONNECT(localhost/127.0.0.1:4454, null)
Jul 20, 2014 2:43:24 PM io.netty.handler.logging.LoggingHandler channelActive
INFO: [id: 0x0f1fc251, /127.0.0.1:33182 => localhost/127.0.0.1:4454] ACTIVE
^Cthufir@dur:~/NetBeansProjects/NettyClient$ 
thufir@dur:~/NetBeansProjects/NettyClient$ 

server code:

package net.bounceme.dur.netty;

import io.netty.channel.ChannelHandler.Sharable;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import java.net.Socket;
import java.util.logging.Logger;

@Sharable
public class PingPongServerHandler extends SimpleChannelInboundHandler<PingPong> {

    private static final Logger log = Logger.getLogger(PingPongServerHandler.class.getName());
    protected Socket socket = null;

    @Override
    protected void channelRead0(ChannelHandlerContext chc, PingPong pingPong) throws Exception {
        log.info(pingPong.getClass().getSimpleName());
        chc.writeAndFlush(new PingPong());
    }

}

client code:

package net.bounceme.dur.netty;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import java.util.logging.Logger;

public class PingPongClientHandler extends SimpleChannelInboundHandler<PingPong> {

    private static final Logger log = Logger.getLogger(PingPongClientHandler.class.getName());

    public PingPongClientHandler() {
    }

    @Override
    protected void channelRead0(ChannelHandlerContext chc, PingPong pingPong) throws Exception {
        log.info("reading...");
        chc.writeAndFlush(new PingPong());
    }
}

adapted from:

https://github.com/netty/netty/tree/4.0/example/src/main/java/io/netty/example/objectecho

branch 4.0

see also:

https://community.jboss.org/wiki/NettyExampleOfPingPongUsingObject

which uses 3.x and not 4.x, and is overly complex for my purposes.

server:

src/
├── net
│   └── bounceme
│       └── dur
│           └── netty
│               ├── EchoServer.java
│               ├── MyProps.java
│               ├── PingPong.java
│               └── PingPongServerHandler.java
└── server.properties

client:

src
├── net
│   └── bounceme
│       └── dur
│           └── netty
│               ├── EchoClient.java
│               ├── MyProps.java
│               ├── PingPongClientHandler.java
│               └── PingPong.java
└── server.properties

I'm trying to adapt the Echo Netty example to use POJO's instead of ByteBuf.

来源：https://stackoverflow.com/questions/24855307/simplest-possible-pojo-echo-with-netty