一、Http 服务
1、项目需求
1）服务器监听8001端口，浏览器发送请求 http://localhost:8001
2）服务器可以回复消息给客户端 “Hello 我是服务器”，并对特定请求资源进行过滤
2、案例代码
2.1、Service
public class HttpService {
public static void main(String[] args) throws Exception {
/*create BossGroup and WorkerGroup*/
EventLoopGroup bossGroup = new NioEventLoopGroup();
EventLoopGroup workerGroup = new NioEventLoopGroup();
try{
/*create server serverBootstrap*/
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(bossGroup,workerGroup)
.channel(NioServerSocketChannel.class)
.childHandler(new HttpServiceInitializer());
ChannelFuture channelFuture = serverBootstrap.bind(8001).sync();
channelFuture.channel().closeFuture().sync();
}finally{
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
}
2.2、ServiceInitializer
public class HttpServiceInitializer extends ChannelInitializer<SocketChannel> {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
/*gain pipeline*/
ChannelPipeline pipeline = ch.pipeline();
/*add http server codec(coder and decoder*/
/*Http Server Codec is and coder and decoder which supported by netty
* it used to tackle the encode and decode task of http request and http response
* */
pipeline.addLast("MyHttpServerCodec",new HttpServerCodec());
/*add a customize handler*/
pipeline.addLast("MyHttpServiceHandler", new HttpServiceHandler());
}
}
2.3、ServiceHandler
/**
* @author 彭友聪
* SimpleChannelInboundHandler is child class of ChannelInboundAdapter
* HttpObject is Encapsulation for the data of communication between server side and client side
*/
public class HttpServiceHandler extends SimpleChannelInboundHandler<HttpObject> {
/**
* this is method used to read the data come from client side
* @param ctx context of channel
* @param msg message from client
* @throws Exception exception
*/
@Override
protected void channelRead0(ChannelHandlerContext ctx, HttpObject msg) throws Exception {
/*verified the msg whether is http request or not*/
if(msg instanceof HttpRequest){
System.out.println("msg type= " + msg.getClass());
System.out.println("client address: " + ctx.channel().remoteAddress());
/*reply information to client, the reply data must use http protocol to encapsulation*/
ByteBuf content = Unpooled.copiedBuffer("Hello I am Server side",
CharsetUtil.UTF_8);
/*build a http response*/
FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1,
HttpResponseStatus.OK, content);
response.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/plain");
response.headers().set(HttpHeaderNames.CONTENT_LENGTH, content.readableBytes());
/*sent the response*/
ctx.writeAndFlush(response);
}
}
}
2.4、请求过滤
/*gain header of client request*/
HttpRequest httpRequest = (HttpRequest) msg;
/*get uri*/
URI uri = new URI(httpRequest.uri());
String path = "/favicon.ico";
if(path.equals(uri.getPath())){
System.out.println("Client has request favicon.ico, not response");
return;
}
在 ServiceHandler 的channelRead0 方法里添加上述代码段，就可以对特定的请求进行过滤，不做响应。
二、WebSocket 长连接
1、案例要求
1）基于WebSocket 实现长连接的全双工交互
2）改变 http 协议多次请求的约束，实现长连接，服务器可以发送消息
3）客户端和服务器端可以相互感知，如服务器关闭了，浏览器会感知；浏览器关闭了，服务器端同样会感知
2、案例代码
2.1、Server
public class Server {
public static void main(String[] args) throws Exception {
EventLoopGroup bossGroup = new NioEventLoopGroup();
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap bootstrap = new ServerBootstrap();
bootstrap
.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
/*add a log handler*/
.handler(new LoggingHandler(LogLevel.INFO))
.childHandler(
new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
pipeline.addLast(new HttpServerCodec());
/*tackle http data which is a data block type*/
pipeline.addLast(new ChunkedWriteHandler());
/*the follow handler can to aggregate(combine) different segment
* of the same http data
* */
pipeline.addLast(new HttpObjectAggregator(8192));
/* the data of websocket sent or gain in the way that used one type called frame
* so that we must use the follow handler to tackle
* in browser we should use the usi: ws://localhost:8001/hello to request server to support
* its service
* WebSocketServerProtocolHandler can upgrade the http protocol into websocket protocol
* so that we can achieve long connect
* */
pipeline.addLast(new WebSocketServerProtocolHandler("/hello"));
/*
* add ourselves' handler of tackle request from browser and handle task of request
* */
pipeline.addLast(new MyWebsocketHandler());
}
});
ChannelFuture future = bootstrap.bind(8001).sync();
future.channel().closeFuture().sync();
} finally {
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
}
2.2、ServerHandler
public class MyWebsocketHandler extends SimpleChannelInboundHandler<TextWebSocketFrame> {
@Override
protected void channelRead0(ChannelHandlerContext ctx, TextWebSocketFrame msg)
throws Exception {
System.out.println("received msg: " + msg.text());
ctx.channel().writeAndFlush(new TextWebSocketFrame("server time: " +
LocalDateTime.now() + msg.text()));
}
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
/*use id().asLongText we can get the Uniquely Identifies of current websocket */
System.out.println(ctx.channel().remoteAddress() + "上线, id=[" +
ctx.channel().id().asLongText() + "]");
}
@Override
public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
System.out.println(ctx.channel().remoteAddress() + "下线, id=[" +
ctx.channel().id().asLongText() + "]");
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
System.out.println("Exception= " + cause.getMessage());
ctx.close();
}
}
2.3、Client
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>WebSocketClient</title>
</head>
<body>
<script>
let socket;
/*Judging current browser whether is support websocket or not*/
if(window.WebSocket){
socket = new WebSocket("ws://localhost:8001/hello");
/*onmessage like read channel, can receive the msg form server*/
socket.onmessage = function (event){
let rt = document.getElementById(`responseText`);
rt.value = rt.value + "\n" + event.data + "\n";
}
socket.onopen = function (event) {
let rt = document.getElementById(`responseText`);
rt.value = "connect startup !!\n";
}
socket.onclose = function (event) {
let rt = document.getElementById(`responseText`);
rt.value = rt.value + "connect shutdown !!\n";
}
}else{
alert("Sorry, your browser is not support websocket");
}
function send(message) {
if(socket.readyState === WebSocket.CLOSED){
alert("Websocket has closed!!");
return;
}
if(socket.readyState === WebSocket.OPEN){
socket.send(message);
}else{
alert("websocket connect has not been built");
}
}
</script>
<form onsubmit="return false">
<label>
<textarea name="msg" style="height: 300px; width: 300px"></textarea>
</label>
<input type="button" value="sent" onclick="send(this.form.msg.value)">
<label for="responseText">服务器回复：</label>
<textarea id="responseText" style="height: 300px; width: 300px"></textarea>
<input type="button" value="清空内容"
onclick="document.getElementById('responseText').value=''">
</form>
</body>
</html>
2.4、测试
在这里插入图片描述