注:源代码来自享学课堂,略有修改,学习之后所做笔记,方便回顾,也给大家一个参考
目录
单播
单播没有服务端和客户端概念
回应端ansoweHandler
和平常的handler没两样,只是writeAndFlush的时候,不是byteBuf,而是DatagramPacket了
public class MyAnswerHandler extends
SimpleChannelInboundHandler<DatagramPacket> {
/**
* 应答的具体内容从常量字符串数组中取得,由nextQuote方法随机获取
*/
private static final String[] DICTIONARY = {
"只要功夫深,铁棒磨成针。",
"旧时王谢堂前燕,飞入寻常百姓家。",
"洛阳亲友如相问,一片冰心在玉壶。",
"一寸光阴一寸金,寸金难买寸光阴。",
"老骥伏枥,志在千里,烈士暮年,壮心不已"};
private static Random r = new Random();
private String nextQuote() {
return DICTIONARY[r.nextInt(DICTIONARY.length - 1)];
}
@Override
protected void channelRead0(ChannelHandlerContext ctx,
DatagramPacket packet)
throws Exception {
//获得请求
String req = packet.content().toString(CharsetUtil.UTF_8);
System.out.println(req);
if (MyUdpQuestion.QUESTION.equals(req)) {
/**
* 重新 new一个DatagramPacket对象,我们通过packet.sender()
* 来获取发送者的地址。
* 重新发送出去!
*/
ctx.writeAndFlush(
new DatagramPacket(
Unpooled.copiedBuffer(
MyUdpAnswer.ANSWER + nextQuote(),
CharsetUtil.UTF_8),
packet.sender()));
}
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
throws Exception {
ctx.close();
cause.printStackTrace();
}
}
回应端主函数
只是channel变成了.channel(NioDatagramChannel.class),其他没有变化
public class MyUdpAnswer {
public final static String ANSWER = "古诗来了:";
public void run(int port) throws Exception {
EventLoopGroup group = new NioEventLoopGroup();
try {
/*和tcp的不同,udp没有接受连接的说法,所以即使是接收端,也使用Bootstrap*/
Bootstrap b = new Bootstrap();
/*由于我们用的是UDP协议,所以要用NioDatagramChannel来创建*/
b.group(group)
.channel(NioDatagramChannel.class)
.handler(new MyAnswerHandler());
//没有接受客户端连接的过程,监听本地端口即可
ChannelFuture f = b.bind(port).sync();
System.out.println("应答服务已启动.....");
f.channel().closeFuture().sync();
} finally {
group.shutdownGracefully();
}
}
public static void main(String[] args) throws Exception {
int port = 8080;
new MyUdpAnswer().run(port);
}
}
发送端
读写数据都是使用DatagramPacket
public class MyQuestionHandler extends
SimpleChannelInboundHandler<DatagramPacket> {
@Override
protected void channelRead0(ChannelHandlerContext ctx, DatagramPacket msg)
throws Exception {
//获得应答,DatagramPacket提供了content()方法取得报文的实际内容
String response = msg.content().toString(CharsetUtil.UTF_8);
if (response.startsWith(MyUdpAnswer.ANSWER)) {
System.out.println(response);
ctx.close();
}
}
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
//将UDP请求的报文以DatagramPacket打包发送给接受端
ctx.writeAndFlush(new DatagramPacket(
Unpooled.copiedBuffer("告诉我一句古诗", CharsetUtil.UTF_8),
new InetSocketAddress("127.0.0.1", 8080)
));
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
throws Exception {
cause.printStackTrace();
ctx.close();
}
}
发送端主函数
ublic class MyUdpQuestion {
public final static String QUESTION = "告诉我一句古诗";
public void run(int port) throws Exception {
EventLoopGroup group = new NioEventLoopGroup();
try {
Bootstrap b = new Bootstrap();
b.group(group)
/*由于我们用的是UDP协议,所以要用NioDatagramChannel来创建*/
.channel(NioDatagramChannel.class)
.handler(new MyQuestionHandler());
//不需要建立连接
Channel ch = b.bind(0).sync().channel();
//不知道接收端能否收到报文,也不知道能否收到接收端的应答报文
// 所以等待15秒后,不再等待,关闭通信
if (!ch.closeFuture().await(15000)) {
System.out.println("查询超时!");
}
} catch (Exception e) {
group.shutdownGracefully();
}
}
public static void main(String[] args) throws Exception {
int answerPort = 8080;
new MyUdpQuestion().run(answerPort);
}
}
执行结果
服务端
应答服务已启动.....
告诉我一句古诗
发送端
古诗来了:旧时王谢堂前燕,飞入寻常百姓家。
广播:模拟日志发送:
广播端:
.option(ChannelOption.SO_BROADCAST,true)
接收端:
//设置套接字选项 SO_BROADCAST
.option(ChannelOption.SO_BROADCAST, true)
//允许端口重用
.option(ChannelOption.SO_REUSEADDR,true)
日志发送对象
@Data
public class LogMsg {
public static final byte SEPARATOR = (byte) ':';
/**
* 源的 InetSocketAddress
*/
private final InetSocketAddress source;
/**
* 消息内容
*/
private final String msg;
/**
* 消息id
*/
private final long msgId;
/**
* 消息发送或者接受的时间
*/
private final long time;
/**
* 用于传入消息的构造函数
*/
public LogMsg(String msg) {
this(null, msg, -1, System.currentTimeMillis());
}
/**
* 用于传出消息的构造函数
*/
public LogMsg(InetSocketAddress source, long msgId,
String msg) {
this(source, msg, msgId, System.currentTimeMillis());
}
public LogMsg(InetSocketAddress source, String msg, long msgId, long time) {
this.source = source;
this.msg = msg;
this.msgId = msgId;
this.time = time;
}
}
日志发送工具
public class LogConst {
public final static int MONITOR_SIDE_PORT = 9998;
private static final String[] LOG_INFOS = {
"20180912:mark-machine:Send sms to 10001",
"20180912:lison-machine:Send email to james@enjoyedu",
"20180912:james-machine:Happen Exception",
"20180912:peter-machine:人生不能象做菜,把所有的料都准备好了才下锅",
"20180912:deer-machine:牵着你的手,就象左手牵右手没感觉,但砍下去也会痛!",
"20180912:king-machine:我听别人说这世界上有一种鸟是没有脚的," +
"它只能一直飞呀飞呀,飞累了就在风里面睡觉,这种鸟一辈子只能下地一次," +
"那一次就是它死亡的时候.",
"20180912:mark-machine:多年以后我有个绰号叫西毒,任何人都可以变得狠毒," +
"只要你尝试过什么叫妒嫉.我不介意其他人怎么看我," +
"我只不过不想别人比我更开心.我以为有一些人永远不会妒嫉," +
"因为他太骄傲 . 在我出道的时候,我认识了一个人," +
"因为他喜欢在东边出没,所以很多年以后,他有个绰号叫东邪.",
"20180912:lison-machine:做人如果没有梦想,那和咸鱼有什么区别",
"20180912:james-machine:恐惧让你沦为囚犯,希望让你重获自由," +
"坚强的人只能救赎自己,伟大的人才能拯救别人." +
"记着,希望是件好东西,而且从没有一样好东西会消逝." +
"忙活,或者等死.",
"20180912:peter-machine:世界上最远的距离不是生和死," +
"而是我站在你的面前却不能说:我爱你",
"20180912:deer-machine:成功的含义不在于得到什么," +
"而是在于你从那个奋斗的起点走了多远.",
"20180912:king-machine:一个人杀了一个人,他是杀人犯.是坏人," +
"当一个人杀了成千上万人后,他是英雄,是大好人",
"20180912:mark-machine:世界在我掌握中,我却掌握不住对你的感情",
"20180912:lison-machine:我害怕前面的路,但是一想到你,就有能力向前走了。",
"20180912:james-machine:早就劝你别吸烟,可是烟雾中的你是那么的美," +
"叫我怎么劝得下口。",
"20180912:peter-machine:如果你只做自己能力范围之内的事情,就永远无法进步。" +
"昨天已成为历史,明天是未知的,而今天是上天赐予我们的礼物," +
"这就是为什么我们把它叫做现在!",
"20180912:deer-machine:年轻的时候有贼心没贼胆,等到了老了吧," +
"贼心贼胆都有了,可贼又没了。",
"20180912:king-machine:别看现在闹得欢,小心将来拉清单。"};
private final static Random r = new Random();
public static String getLogInfo(){
return LOG_INFOS[r.nextInt(LOG_INFOS.length-1)];
}
}
广播主函数
public class LogEventBroadcaster {
private final EventLoopGroup group;
private final Bootstrap bootstrap;
public LogEventBroadcaster(InetSocketAddress remoteAddress) {
group = new NioEventLoopGroup();
bootstrap = new Bootstrap();
//引导该 NioDatagramChannel(无连接的)
bootstrap.group(group).channel(NioDatagramChannel.class)
//设置 SO_BROADCAST 套接字选项
.option(ChannelOption.SO_BROADCAST,true)
.handler(new LogEventEncoder(remoteAddress));
}
public void run() throws Exception {
//绑定 Channel
Channel ch = bootstrap.bind(0).sync().channel();
long count = 0;
//启动主处理循环,模拟日志发送
for (;;) {
ch.writeAndFlush(new LogMsg(null, ++count,
LogConst.getLogInfo()));
try {
//休眠 2 秒,如果被中断,则退出循环;
Thread.sleep(2000);
} catch (InterruptedException e) {
Thread.interrupted();
break;
}
}
}
public void stop() {
group.shutdownGracefully();
}
public static void main(String[] args) throws Exception {
//创建并启动一个新的 UdpQuestionSide 的实例
LogEventBroadcaster broadcaster = new LogEventBroadcaster(
//表明本应用发送的报文并没有一个确定的目的地,也就是进行广播
new InetSocketAddress("255.255.255.255",
LogConst.MONITOR_SIDE_PORT));
try {
broadcaster.run();
}
finally {
broadcaster.stop();
}
}
}
广播主函数编码
public class LogEventEncoder extends MessageToMessageEncoder<LogMsg> {
private final InetSocketAddress remoteAddress;
/**
* LogEventEncoder 创建了即将被发送到指定的 InetSocketAddress的 DatagramPacket 消息
*/
public LogEventEncoder(InetSocketAddress remoteAddress) {
this.remoteAddress = remoteAddress;
}
@Override
protected void encode(ChannelHandlerContext channelHandlerContext,
LogMsg logMsg, List<Object> out) throws Exception {
byte[] msg = logMsg.getMsg().getBytes(CharsetUtil.UTF_8);
//容量的计算:两个long型+消息的内容+分割符
ByteBuf buf = channelHandlerContext.alloc()
.buffer(8*2 + msg.length + 1);
//将发送时间写入到 ByteBuf中
buf.writeLong(logMsg.getTime());
//将消息id写入到 ByteBuf中
buf.writeLong(logMsg.getMsgId());
//添加一个 SEPARATOR
buf.writeByte(LogMsg.SEPARATOR);
//将日志消息写入 ByteBuf中
buf.writeBytes(msg);
//将一个拥有数据和目的地地址的新 DatagramPacket 添加到出站的消息列表中
out.add(new DatagramPacket(buf, remoteAddress));
}
}
广播接收者
public class LogEventMonitor {
private final EventLoopGroup group;
private final Bootstrap bootstrap;
public LogEventMonitor(InetSocketAddress address) {
group = new NioEventLoopGroup();
bootstrap = new Bootstrap();
//引导该 NioDatagramChannel
bootstrap.group(group)
.channel(NioDatagramChannel.class)
//设置套接字选项 SO_BROADCAST
.option(ChannelOption.SO_BROADCAST, true)
//允许端口重用
.option(ChannelOption.SO_REUSEADDR,true)
.handler( new ChannelInitializer<Channel>() {
@Override
protected void initChannel(Channel channel)
throws Exception {
ChannelPipeline pipeline = channel.pipeline();
pipeline.addLast(new LogEventDecoder());
pipeline.addLast(new LogEventHandler());
}
} )
.localAddress(address);
}
public Channel bind() {
//绑定 Channel。注意,DatagramChannel 是无连接的
return bootstrap.bind().syncUninterruptibly().channel();
}
public void stop() {
group.shutdownGracefully();
}
public static void main(String[] args) throws Exception {
//构造一个新的 UdpAnswerSide并指明监听端口
LogEventMonitor monitor = new LogEventMonitor(
new InetSocketAddress(LogConst.MONITOR_SIDE_PORT));
try {
//绑定本地监听端口
Channel channel = monitor.bind();
System.out.println("UdpAnswerSide running");
channel.closeFuture().sync();
} finally {
monitor.stop();
}
}
}
广播接受者handler
public class LogEventHandler
extends SimpleChannelInboundHandler<LogMsg> {
@Override
public void exceptionCaught(ChannelHandlerContext ctx,
Throwable cause) throws Exception {
//当异常发生时,打印栈跟踪信息,并关闭对应的 Channel
cause.printStackTrace();
ctx.close();
}
@Override
public void channelRead0(ChannelHandlerContext ctx,
LogMsg event) throws Exception {
//创建 StringBuilder,并且构建输出的字符串
StringBuilder builder = new StringBuilder();
builder.append(event.getTime());
builder.append(" [");
builder.append(event.getSource().toString());
builder.append("] :[");
builder.append(event.getMsgId());
builder.append("] :");
builder.append(event.getMsg());
//打印 LogMsg 的数据
System.out.println(builder.toString());
}
}
接受者解码
public class LogEventDecoder extends MessageToMessageDecoder<DatagramPacket> {
@Override
protected void decode(ChannelHandlerContext ctx,
DatagramPacket datagramPacket, List<Object> out)
throws Exception {
//获取对 DatagramPacket 中的数据(ByteBuf)的引用
ByteBuf data = datagramPacket.content();
//获得发送时间
long sendTime = data.readLong();
System.out.println("接受到"+sendTime+"发送的消息");
//获得消息的id
long msgId = data.readLong();
//获得分隔符SEPARATOR
byte sepa = data.readByte();
//获取读索引的当前位置,就是分隔符的索引+1
int idx = data.readerIndex();
//提取日志消息,从读索引开始,到最后为日志的信息
String sendMsg = data.slice(idx ,
data.readableBytes()).toString(CharsetUtil.UTF_8);
//构建一个新的 LogMsg 对象,并且将它添加到(已经解码的消息的)列表中
LogMsg event = new LogMsg(datagramPacket.sender(),
msgId, sendMsg);
//作为本handler的处理结果,交给后面的handler进行处理
out.add(event);
}
}
结果
接受者接收到的日志
接受到1590052211879发送的消息
1590052211962 [/172.17.4.102:61921] :[1] :20180912:lison-machine:做人如果没有梦想,那和咸鱼有什么区别
接受到1590052213884发送的消息
1590052213884 [/172.17.4.102:61921] :[2] :20180912:lison-machine:Send email to james@enjoyedu