nio学习之netty入门（3）---发送对象

1、项目结构：

看下项目的结构：

2、项目源码：

2.1、服务器端：

EchoServer.java

package send_object.server;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import send_object.coder.PersonDecoder;

/**
* • 配置服务器功能，如线程、端口 • 实现服务器处理程序，它包含业务逻辑，决定当有一个请求连接或接收数据时该做什么
*
*/
public class EchoServer {

private final int port;

public EchoServer(int port) {
this.port = port;
}

public void start() throws Exception {
EventLoopGroup eventLoopGroup = null;
try {
//创建ServerBootstrap实例来引导绑定和启动服务器
ServerBootstrap serverBootstrap = new ServerBootstrap();
//创建NioEventLoopGroup对象来处理事件，如接受新连接、接收数据、写数据等等
eventLoopGroup = new NioEventLoopGroup();
//指定通道类型为NioServerSocketChannel，一种异步模式，OIO阻塞模式为OioServerSocketChannel
//设置InetSocketAddress让服务器监听某个端口已等待客户端连接。
serverBootstrap.group(eventLoopGroup).channel(NioServerSocketChannel.class).localAddress("localhost",port)
.childHandler(new ChannelInitializer<Channel>() {
//设置childHandler执行所有的连接请求
@Override
protected void initChannel(Channel ch) throws Exception {
//注册解码的handler
ch.pipeline().addLast(new PersonDecoder());  //IN1  反序列化
//添加一个入站的handler到ChannelPipeline
ch.pipeline().addLast(new EchoServerHandler());   //IN2
}
});
// 最后绑定服务器等待直到绑定完成，调用sync()方法会阻塞直到服务器完成绑定,然后服务器等待通道关闭，因为使用sync()，所以关闭操作也会被阻塞。
ChannelFuture channelFuture = serverBootstrap.bind().sync();
System.out.println("开始监听，端口为：" + channelFuture.channel().localAddress());
channelFuture.channel().closeFuture().sync();
} finally {
eventLoopGroup.shutdownGracefully().sync();
}
}

public static void main(String[] args) throws Exception {
new EchoServer(20000).start();
}
}

EchoServerHandler.java

package send_object.server;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import send_object.bean.Person;

import java.util.Date;

public class EchoServerHandler extends ChannelInboundHandlerAdapter {

@Override
public void channelRead(ChannelHandlerContext ctx, Object msg)
throws Exception {
System.out.println("接收客户端消息：");
Person person = (Person) msg;
System.out.println(person.getName());
System.out.println(person.getAge());
System.out.println(person.getSex());

//向客户端写数据
System.out.println("server向client发送数据");
String currentTime = new Date(System.currentTimeMillis()).toString();
ByteBuf resp = Unpooled.copiedBuffer(currentTime.getBytes());
ctx.write(resp);
}

@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
System.out.println("server 读取数据完毕..");

ctx.flush();//刷新后才将数据发出到SocketChannel
}

@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
throws Exception {
cause.printStackTrace();
ctx.close();
}

}

2.2、客户端：

EchoClient.java

package send_object.client;

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
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 send_object.coder.PersonEncoder;

import java.net.InetSocketAddress;

/**
* • 连接服务器 • 写数据到服务器 • 等待接受服务器返回相同的数据 • 关闭连接
*
* @author wilson
*
*/
public class EchoClient {

private final String host;
private final int port;

public EchoClient(String host, int port) {
this.host = host;
this.port = port;
}

public void start() throws Exception {
EventLoopGroup nioEventLoopGroup = null;
try {
// 创建Bootstrap对象用来引导启动客户端
Bootstrap bootstrap = new Bootstrap();
// 创建EventLoopGroup对象并设置到Bootstrap中，EventLoopGroup可以理解为是一个线程池，这个线程池用来处理连接、接受数据、发送数据
nioEventLoopGroup = new NioEventLoopGroup();
// 创建InetSocketAddress并设置到Bootstrap中，InetSocketAddress是指定连接的服务器地址
bootstrap.group(nioEventLoopGroup)//
.channel(NioSocketChannel.class)//
.remoteAddress(new InetSocketAddress(host, port))//
.handler(new ChannelInitializer<SocketChannel>() {//
// 添加一个ChannelHandler，客户端成功连接服务器后就会被执行
@Override
protected void initChannel(SocketChannel ch)
throws Exception {
// 注册编码的handler
ch.pipeline().addLast(new PersonEncoder());  //out
//注册处理消息的handler
ch.pipeline().addLast(new EchoClientHandler());   //in
}
});
// • 调用Bootstrap.connect()来连接服务器
ChannelFuture f = bootstrap.connect().sync();
// • 最后关闭EventLoopGroup来释放资源
f.channel().closeFuture().sync();
} finally {
nioEventLoopGroup.shutdownGracefully().sync();
}
}

public static void main(String[] args) throws Exception {
new EchoClient("localhost", 20000).start();
}
}

EchoClientHandler.java

package send_object.client;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import send_object.bean.Person;

public class EchoClientHandler extends SimpleChannelInboundHandler<ByteBuf> {
// 客户端连接服务器后被调用
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
Person person = new Person();
person.setName("angelababy");
person.setSex("girl");
person.setAge(18);
ctx.write(person);
ctx.flush();
}

// • 从服务器接收到数据后调用
@Override
protected void channelRead0(ChannelHandlerContext ctx, ByteBuf msg)
throws Exception {
System.out.println("client 读取server数据..");
// 服务端返回消息后
//      ByteBuf buf = (ByteBuf) msg;
//      byte[] req = new byte[buf.readableBytes()];
//      buf.readBytes(req);
byte[] req = new byte[msg.readableBytes()];
msg.readBytes(req);
String body = new String(req, "UTF-8");
System.out.println("服务端数据为 :" + body);
}

// • 发生异常时被调用
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
throws Exception {
System.out.println("client exceptionCaught..");
// 释放资源
ctx.close();
}
}

2.3、其他：

Person.java

package send_object.bean;

import java.io.Serializable;

public class Person implements Serializable {
private static final long serialVersionUID = 1L;
private String name;
private String sex;
private int age;

public String toString() {
return "name:" + name + " sex:" + sex + " age:" + age;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public String getSex() {
return sex;
}

public void setSex(String sex) {
this.sex = sex;
}

public int getAge() {
return age;
}

public void setAge(int age) {
this.age = age;
}
}

PersonDecoder.java

package send_object.coder;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.ByteToMessageDecoder;
import send_object.utils.ByteBufToBytes;
import send_object.utils.ByteObjConverter;

import java.util.List;

/**
* 反序列化
* 将Byte[]转换为Object
* @author wilson
*
*/
public class PersonDecoder extends ByteToMessageDecoder {
@Override
protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
//工具类：将ByteBuf转换为byte[]
ByteBufToBytes read = new ByteBufToBytes();
byte[] bytes = read.read(in);
//工具类：将byte[]转换为object
Object obj = ByteObjConverter.byteToObject(bytes);
out.add(obj);
}

}

PersonEncoder.java

package send_object.coder;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToByteEncoder;
import send_object.bean.Person;
import send_object.utils.ByteObjConverter;

/**
* 序列化
* 将object转换成Byte[]
* @author wilson
*
*/
public class PersonEncoder extends MessageToByteEncoder<Person> {

@Override
protected void encode(ChannelHandlerContext ctx, Person msg, ByteBuf out) throws Exception {
//工具类：将object转换为byte[]
byte[] datas = ByteObjConverter.objectToByte(msg);
out.writeBytes(datas);
ctx.flush();
}
}

ByteBufToBytes.java

package send_object.utils;

import io.netty.buffer.ByteBuf;

public class ByteBufToBytes {
/**
* 将ByteBuf转换为byte[]
* @param datas
* @return
*/
public byte[] read(ByteBuf datas) {
byte[] bytes = new byte[datas.readableBytes()];// 创建byte[]
datas.readBytes(bytes);// 将ByteBuf转换为byte[]
return bytes;
}
}

ByteObjConverter.java

package send_object.utils;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;

public class ByteObjConverter {
/**
* 使用IO的inputstream流将byte[]转换为object
* @param bytes
* @return
*/
public static Object byteToObject(byte[] bytes) {
Object obj = null;
ByteArrayInputStream bi = new ByteArrayInputStream(bytes);
ObjectInputStream oi = null;
try {
oi = new ObjectInputStream(bi);
obj = oi.readObject();
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
bi.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
oi.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return obj;
}
/**
* 使用IO的outputstream流将object转换为byte[]
* @param obj
* @return
*/
public static byte[] objectToByte(Object obj) {
byte[] bytes = null;
ByteArrayOutputStream bo = new ByteArrayOutputStream();
ObjectOutputStream oo = null;
try {
oo = new ObjectOutputStream(bo);
oo.writeObject(obj);
bytes = bo.toByteArray();
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
bo.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
oo.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return bytes;
}
}

3、最后结果：

服务器端：

开始监听，端口为：/127.0.0.1:20000
接收客户端消息：
angelababy
18
girl
server向client发送数据
server 读取数据完毕..

客户端：

client 读取server数据..
服务端数据为 :Thu Dec 22 10:32:34 CST 2016