Question

netty4 能不能运行在android上

Answer 1

是哪些
在修改androidpn，感觉xmpp协议太重了，而且据说很耗流量很耗电。
mina2两年没更新了！spring mvc 竟然还用的是2.5
= - =想迁移到netty4，把xmpp改成轻量的protobuf，但是不知道android上能否流畅使用netty4
netty4的jar包，服务端不要紧可以使用all-in-one，android端怎么使用？最小依赖是哪些
坐等大神解惑，感激不尽。

Answer 2

netty-buffer-4.0.17.Final.jar

netty-codec-4.0.17.Final.jar

netty-common-4.0.17.Final.jar

netty-handler-4.0.17.Final.jar

netty-transport-4.0.17.Final.jar

bootstrap = new Bootstrap();
bootstrap.group(new NioEventLoopGroup());
bootstrap.channelFactory(new ChannelFactory<NioSocketChannel>(){
@Override
public NioSocketChannel newChannel() {
NioSocketChannel channel=new NioSocketChannel();
Log.d("ClientConnection", PooledByteBufAllocator.DEFAULT.toString());
channel.config().setAllocator(PooledByteBufAllocator.DEFAULT);
return channel;
}
});

解决传输文件的时候爆没有sun buf类的问题
channel.config().setAllocator(PooledByteBufAllocator.DEFAULT);

Answer 3

相比Netty3, Netty4有很多显著的变化：
NioEventLoopGroup 是一个处理I/O操作的多线程事件环。即为Netty4里的线程池，在3.x里，一个Channel是由ChannelFactory创建的，同时新创建的Channel会自动注册到一个隐藏的I/O线程。 4.0使用新的名为EventLoopGroup的接口来替换ChannelFactory，它由一个或多个EventLoop来构成。一个新的 Channel不会自动注册到EventLoopGroup，但用户可以显式调用EventLoopGroup.register（）来注册。在Server端的Bootstrap参数中，有两个EventLoopGroup，第一个通常称为'boss'，用于接收发来的连接请求。第二个称为'worker',，用于处理boss接受并且注册给worker的连接中的信息。

ChannelInitializer是一个特殊的handler，用于方便的配置用户自定义的handler实现，如代码中所示。在channelRegistered的生命周期中会触发用户复写的initChannel(C ch)方法，并且在调用后会讲自身从channelPipeline中移除。
代码示例
?
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.serialization.ClassResolvers;
import io.netty.handler.codec.serialization.ObjectDecoder;
import io.netty.handler.codec.serialization.ObjectEncoder;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import io.netty.handler.ssl.SslContext;
import io.netty.handler.ssl.util.SelfSignedCertificate;

/**
* DateTime: 2015年1月5日 上午9:56:10
*
*/
public class HelloWorldServer {
static final boolean SSL = System.getProperty("ssl") != null;
static final int PORT = Integer.parseInt(System.getProperty("port", "8007"));

public static void main(String[] args) throws Exception {
// Configure SSL.
final SslContext sslCtx;
if (SSL) {
SelfSignedCertificate ssc = new SelfSignedCertificate();
sslCtx = SslContext.newServerContext(ssc.certificate(), ssc.privateKey());
} else {
sslCtx = null;
}

// Configure the server.
EventLoopGroup bossGroup = new NioEventLoopGroup(1);
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 {
ChannelPipeline p = ch.pipeline();
if (sslCtx != null) {
p.addLast(sslCtx.newHandler(ch.alloc()));
}
p.addLast(new LoggingHandler(LogLevel.INFO));
p.addLast(
new ObjectEncoder(),
new ObjectDecoder(ClassResolvers.cacheDisabled(null)),
new HelloWorldServerHandler());
}
});

// Start the server.
ChannelFuture f = b.bind(PORT).sync();

// Wait until the server socket is closed.
f.channel().closeFuture().sync();
} finally {
// Shut down all event loops to terminate all threads.
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
}

class HelloWorldServerHandler extends ChannelInboundHandlerAdapter {

@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) {
ctx.write("server write msg:"+msg);
}

@Override
public void channelReadComplete(ChannelHandlerContext ctx) {
ctx.flush();
}

@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
// Close the connection when an exception is raised.
cause.printStackTrace();
ctx.close();
}
}
import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.serialization.ClassResolvers;
import io.netty.handler.codec.serialization.ObjectDecoder;
import io.netty.handler.codec.serialization.ObjectEncoder;
import io.netty.handler.ssl.SslContext;
import io.netty.handler.ssl.util.InsecureTrustManagerFactory;

/**
* DateTime: 2015年1月5日 上午9:56:22
*
*/
public class HelloWorldClient {
static final boolean SSL = System.getProperty("ssl") != null;
static final String HOST = System.getProperty("host", "127.0.0.1");
static final int PORT = Integer.parseInt(System.getProperty("port", "8007"));

public static void main(String[] args) throws Exception {
// Configure SSL.git
final SslContext sslCtx;
if (SSL) {
sslCtx = SslContext.newClientContext(InsecureTrustManagerFactory.INSTANCE);
}
else {
sslCtx = null;
}

// Configure the client.
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 {
ChannelPipeline p = ch.pipeline();
if (sslCtx != null) {
p.addLast(sslCtx.newHandler(ch.alloc(), HOST, PORT));
}
p.addLast(new ObjectEncoder(), new ObjectDecoder(ClassResolvers.cacheDisabled(null)),
new HelloWorldClientHandler());
}
});

// Start the client.
ChannelFuture f = b.connect(HOST, PORT).sync();

// Wait until the connection is closed.
f.channel().closeFuture().sync();
}
finally {
// Shut down the event loop to terminate all threads.
group.shutdownGracefully();
}
}
}

class HelloWorldClientHandler extends ChannelInboundHandlerAdapter {

private final String msg = "hello java world";

/**
* Creates a client-side handler.
*/
public HelloWorldClientHandler() {
//TODO
}

@Override
public void channelActive(ChannelHandlerContext ctx) {
ctx.writeAndFlush(msg);
}

@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) {
System.out.println(msg);
// ctx.write(msg);
}

@Override
public void channelReadComplete(ChannelHandlerContext ctx) {
ctx.flush();
}

@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
// Close the connection when an exception is raised.
cause.printStackTrace();
ctx.close();
}
}