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使用Netty传输POJO对象，重点在于对象的序列化，序列化后的对象可以通过TCP流进行网络传输，结合Netty提供的对象编解码器，可以做到远程传输对象。
下面我们来看一个例子：模拟订票
首先Java序列化的POJO对象需要实现java.io.Serializable接口。
火车车次和余票量POJO：
package bookticket;
import java.io.Serializable;
/**
* 火车pojo对象
* @author xwalker
*/
public class Train implements Serializable {
private static final long serialVersionUID = 1510326612440404416L;
private String number;//火车车次
private int ticketCounts;//余票数量
public Train(String number,int ticketCounts){
this.number=number;
this.ticketCounts=ticketCounts;
}
public String getNumber() {
return number;
}
public void setNumber(String number) {
this.number = number;
}
public int getTicketCounts() {
return ticketCounts;
}
public void setTicketCounts(int ticketCounts) {
this.ticketCounts = ticketCounts;
}
}
车票POJO：
package bookticket;
import java.io.Serializable;
import java.util.Date;
/**
* 订票POJO对象
* @author xwalker
*/
public class Ticket implements Serializable {
private static final long serialVersionUID = 4228051882802183587L;
private String trainNumber;//火车车次
private int carriageNumber;//车厢编号
private String seatNumber;//座位编号
private String number;//车票编号
private User user;//订票用户
private Date bookTime;//订票时间
private Date startTime;//开车时间
public String getNumber() {
return number;
}
public void setNumber(String number) {
this.number = number;
}
public Date getBookTime() {
return bookTime;
}
public void setBookTime(Date bookTime) {
this.bookTime = bookTime;
}
public Date getStartTime() {
return startTime;
}
public void setStartTime(Date startTime) {
this.startTime = startTime;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
public String getTrainNumber() {
return trainNumber;
}
public void setTrainNumber(String trainNumber) {
this.trainNumber = trainNumber;
}
public int getCarriageNumber() {
return carriageNumber;
}
public void setCarriageNumber(int carriageNumber) {
this.carriageNumber = carriageNumber;
}
public String getSeatNumber() {
return seatNumber;
}
public void setSeatNumber(String seatNumber) {
this.seatNumber = seatNumber;
}
}
用户POJO：
package bookticket;
import java.io.Serializable;
/**
* 用户POJO对象
* @author xwalker
*/
public class User implements Serializable {
private static final long serialVersionUID = -3845514510571408376L;
private String userId;//身份证
private String userName;//姓名
private String phone;//电话
private String email;//邮箱
public String getUserId() {
return userId;
}
public void setUserId(String userId) {
this.userId = userId;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getPhone() {
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}
请求指令集：
package bookticket;
/**
* 指令集
* @author xwalker
*
*/
public class Code {
public static final int CODE_SEARCH=1;//查询车票余量
public static final int CODE_BOOK=2;//订票
public static final int CODE_NONE=-1;//错误指令 无法处理
}
客户端发送的请求信息：
package bookticket;
import java.io.Serializable;
import java.util.Date;
/**
* 订票人发送查询余票和订票使用的请求信息
* @author xwalker
*
*/
public class BookRequestMsg implements Serializable {
private static final long serialVersionUID = -7335293929249462183L;
private User user;//发送订票信息用户
private String trainNumber;//火车车次
private int code;//查询命令
private Date startTime;//开车时间
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
public String getTrainNumber() {
return trainNumber;
}
public void setTrainNumber(String trainNumber) {
this.trainNumber = trainNumber;
}
public Date getStartTime() {
return startTime;
}
public void setStartTime(Date startTime) {
this.startTime = startTime;
}
public int getCode() {
return code;
}
public void setCode(int code) {
this.code = code;
}
}
服务器接收订票和查票后处理完业务反馈客户端的信息：
package bookticket;
import java.io.Serializable;
import java.util.Date;
/**
* 订票成功与否反馈信息
* @author xwalker
*/
public class BookResponseMsg implements Serializable {
private static final long serialVersionUID = -4984721370227929766L;
private boolean success;//是否操作成功
private User user;//请求用户
private String msg;//反馈信息
private int code;//请求指令
private Train train;//火车车次
private Date startTime;//出发时间
private Ticket ticket;//订票成功后具体出票票据
public boolean getSuccess() {
return success;
}
public void setSuccess(boolean success) {
this.success = success;
}
public String getMsg() {
return msg;
}
public void setMsg(String msg) {
this.msg = msg;
}
public Ticket getTicket() {
return ticket;
}
public void setTicket(Ticket ticket) {
this.ticket = ticket;
}
public int getCode() {
return code;
}
public void setCode(int code) {
this.code = code;
}
public Train getTrain() {
return train;
}
public void setTrain(Train train) {
this.train = train;
}
public Date getStartTime() {
return startTime;
}
public void setStartTime(Date startTime) {
this.startTime = startTime;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
}
订票服务器：
package bookticket;
import java.util.ArrayList;
import java.util.List;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
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;
/**
* 订票服务器端
* @author xwalker
*
*/
public class BookTicketServer {
public static List<Train> trains;
/**
* 初始化 构造车次和车票余数
*/
public BookTicketServer() {
trains=new ArrayList<Train>();
trains.add(new Train("G242",500));
trains.add(new Train("G243",200));
trains.add(new Train("D1025",100));
trains.add(new Train("D1235",0));
}
public void bind(int port) throws Exception{
//配置NIO线程组
EventLoopGroup bossGroup=new NioEventLoopGroup();
EventLoopGroup workerGroup=new NioEventLoopGroup();
try{
//服务器辅助启动类配置
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
protected void initChannel(SocketChannel ch) throws Exception {
//添加对象解码器 负责对序列化POJO对象进行解码 设置对象序列化最大长度为1M 防止内存溢出
//设置线程安全的WeakReferenceMap对类加载器进行缓存 支持多线程并发访问 防止内存溢出
ch.pipeline().addLast(new ObjectDecoder(1024*1024,ClassResolvers.weakCachingConcurrentResolver(this.getClass().getClassLoader())));
//添加对象编码器 在服务器对外发送消息的时候自动将实现序列化的POJO对象编码
ch.pipeline().addLast(new ObjectEncoder());
ch.pipeline().addLast(new BookTicketServerhandler());
}
});
//绑定端口 同步等待绑定成功
ChannelFuture f=b.bind(port).sync();
//等到服务端监听端口关闭
f.channel().closeFuture().sync();
}finally{
//优雅释放线程资源
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
public static void main(String[] args) throws Exception {
int port =8000;
new BookTicketServer().bind(port);
}
}
服务器端网络IO处理器，查票订票业务处理和反馈：
package bookticket;
import java.util.Date;
import java.util.Random;
import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;
/**
* 订票server端处理器
* @author xwalker
*
*/
public class BookTicketServerhandler extends ChannelHandlerAdapter {
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg)
throws Exception {
BookRequestMsg requestMsg=(BookRequestMsg) msg;
BookResponseMsg responseMsg=null;
switch (requestMsg.getCode()) {
case Code.CODE_SEARCH://查询余票
for(Train train:BookTicketServer.trains){
//找到车次与请求车次相同的 返回车次余票
if(requestMsg.getTrainNumber().equals(train.getNumber())){
responseMsg=new BookResponseMsg();
responseMsg.setUser(requestMsg.getUser());
responseMsg.setCode(Code.CODE_SEARCH);
responseMsg.setSuccess(true);
responseMsg.setTrain(train);
responseMsg.setStartTime(requestMsg.getStartTime());
responseMsg.setMsg("火车【"+train.getNumber()+"】余票数量为【"+train.getTicketCounts()+"】");
break;
}
}
if(responseMsg==null){
responseMsg=new BookResponseMsg();
responseMsg.setUser(requestMsg.getUser());
responseMsg.setCode(Code.CODE_SEARCH);
responseMsg.setSuccess(false);
responseMsg.setMsg("火车【"+requestMsg.getTrainNumber()+"】的信息不存在！");
}
break;
case Code.CODE_BOOK://确认订票
for(Train train:BookTicketServer.trains){
//找到车次与请求车次相同的 返回车次余票
if(requestMsg.getTrainNumber().equals(train.getNumber())){
responseMsg=new BookResponseMsg();
responseMsg.setUser(requestMsg.getUser());
responseMsg.setSuccess(true);
responseMsg.setCode(Code.CODE_BOOK);
responseMsg.setMsg("恭喜您，订票成功！");
Ticket ticket=new Ticket();
ticket.setBookTime(new Date());
ticket.setUser(requestMsg.getUser());
ticket.setStartTime(requestMsg.getStartTime());
ticket.setNumber(train.getNumber()+System.currentTimeMillis());//生成车票编号
ticket.setCarriageNumber(new Random().nextInt(15));//随机车厢
ticket.setUser(requestMsg.getUser());//设置订票人信息
String[] seat=new String[]{"A","B","C","D","E"};
Random seatRandom=new Random();
ticket.setSeatNumber(seat[seatRandom.nextInt(5)]+seatRandom.nextInt(100));
ticket.setTrainNumber(train.getNumber());
train.setTicketCounts(train.getTicketCounts()-1);//余票减去一张
responseMsg.setTrain(train);
responseMsg.setTicket(ticket);
break;
}
}
if(responseMsg==null){
responseMsg=new BookResponseMsg();
responseMsg.setUser(requestMsg.getUser());
responseMsg.setCode(Code.CODE_BOOK);
responseMsg.setSuccess(false);
responseMsg.setMsg("火车【"+requestMsg.getTrainNumber()+"】的信息不存在！");
}
break;
default://无法处理
responseMsg=new BookResponseMsg();
responseMsg.setUser(requestMsg.getUser());
responseMsg.setCode(Code.CODE_NONE);
responseMsg.setSuccess(false);
responseMsg.setMsg("指令无法处理！");
break;
}
ctx.writeAndFlush(responseMsg);
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
throws Exception {
cause.printStackTrace();
ctx.close();
}
}
客户端：
package bookticket;
import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
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;
/**
* 订票客户端
* @author xwalker
*/
public class BookTicketClient {
public void connect(int port,String host) throws Exception{
//配置客户端线程组
EventLoopGroup group=new NioEventLoopGroup();
try{
//配置客户端启动辅助类
Bootstrap b=new Bootstrap();
b.group(group).channel(NioSocketChannel.class)
.option(ChannelOption.TCP_NODELAY, true)
.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
//添加POJO对象解码器 禁止缓存类加载器
ch.pipeline().addLast(new ObjectDecoder(1024,ClassResolvers.cacheDisabled(this.getClass().getClassLoader())));
//设置发送消息编码器
ch.pipeline().addLast(new ObjectEncoder());
//设置网络IO处理器
ch.pipeline().addLast(new BookTicketClientHandler());
}
});
//发起异步服务器连接请求 同步等待成功
ChannelFuture f=b.connect(host,port).sync();
//等到客户端链路关闭
f.channel().closeFuture().sync();
}finally{
//优雅释放线程资源
group.shutdownGracefully();
}
}
public static void main(String[] args) throws Exception{
new BookTicketClient().connect(8000, "127.0.0.1");
}
}
客户端处理网络IO处理器 发送查票和订票请求：
package bookticket;
import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;
import java.util.Calendar;
/**
* 客户端处理器
*
* @author xwalker
*/
public class BookTicketClientHandler extends ChannelHandlerAdapter {
private User user;
public BookTicketClientHandler() {
user=new User();
user.setUserName("xwalker");
user.setPhone("187667*****");
user.setEmail("909854136@qq.com");
user.setUserId("3705231988********");
}
/**
* 链路链接成功
*/
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
// 链接成功后发送查询某车次余票的请求
Calendar c = Calendar.getInstance();
c.set(Calendar.YEAR, 2015);
c.set(Calendar.MONTH, 1);
c.set(Calendar.DATE, 2);
c.set(Calendar.HOUR, 11);
c.set(Calendar.MINUTE, 30);
// G242查询余票
BookRequestMsg requestMsg1 = new BookRequestMsg();
requestMsg1.setCode(Code.CODE_SEARCH);
requestMsg1.setStartTime(c.getTime());
requestMsg1.setTrainNumber("G242");//设置查询车次
requestMsg1.setUser(user);//设置当前登陆用户
ctx.write(requestMsg1);
// D1235查询余票
BookRequestMsg requestMsg2 = new BookRequestMsg();
requestMsg2.setCode(Code.CODE_SEARCH);
requestMsg2.setStartTime(c.getTime());
requestMsg2.setTrainNumber("D1235");//设置查询车次
requestMsg2.setUser(user);
ctx.write(requestMsg2);
ctx.flush();
}
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg)
throws Exception {
BookResponseMsg responseMsg = (BookResponseMsg) msg;
switch (responseMsg.getCode()) {
case Code.CODE_SEARCH://收到查询结果
System.out.println("==========火车【"+responseMsg.getTrain().getNumber()+"】余票查询结果:【"+(responseMsg.getSuccess()?"成功":"失败")+"】=========");
System.out.println(responseMsg.getMsg());
//查询发现有余票的话 需要发送订票指令
if(responseMsg.getTrain().getTicketCounts()>0){
//构造查询有余票的火车的订票指令
BookRequestMsg requestMsg = new BookRequestMsg();
requestMsg.setCode(Code.CODE_BOOK);
requestMsg.setUser(user);
requestMsg.setStartTime(responseMsg.getStartTime());
requestMsg.setTrainNumber(responseMsg.getTrain().getNumber());
ctx.writeAndFlush(requestMsg);
}else{
System.out.println("火车【"+responseMsg.getTrain().getNumber()+"】没有余票，不能订票了！");
}
break;
case Code.CODE_BOOK://收到订票结果
System.out.println("==========火车【"+responseMsg.getTrain().getNumber()+"】订票结果:【"+(responseMsg.getSuccess()?"成功":"失败")+"】=========");
System.out.println(responseMsg.getMsg());
System.out.println("========车票详情========");
Ticket ticket=responseMsg.getTicket();
System.out.println("车票票号：【"+ticket.getNumber()+"】");
System.out.println("火车车次：【"+ticket.getTrainNumber()+"】");
System.out.println("火车车厢：【"+ticket.getCarriageNumber()+"】");
System.out.println("车厢座位：【"+ticket.getSeatNumber()+"】");
System.out.println("预定时间：【"+ticket.getBookTime()+"】");
System.out.println("出发时间：【"+ticket.getStartTime()+"】");
System.out.println("乘客信息：【"+ticket.getUser().getUserName()+"】");
break;
default:
System.out.println("==========操作错误结果=========");
System.out.println(responseMsg.getMsg());
break;
}
}
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
ctx.flush();
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
throws Exception {
cause.printStackTrace();
ctx.close();
}
}
最后测试结果：
Netty5入门学习笔记004-使用Netty传输POJO对象（上）
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原文地址：http://my.oschina.net/imhoodoo/blog/361076
