我想使用Netty编写一个简单的程序，用于代理浏览器发送的HTTP请求。我认为它可以分为三个步骤：
1. 获取浏览器发送的请求。
2. 将请求发送到网站。
3. 接收网站数据并将其发送回浏览器。
问题：
1. 当我使用Bootstrap.connect（主机，端口）时，如何将URL翻译成主机和端口？
2. 当我使用HttpServerResponseHandler.connect和ChannelHandlerContext.writeAndFlush（httpMessage）向网站发送数据时，如何获取来自网站的响应数据并将其发送回浏览器？
这是我学习Netty的第一天，请尽量简单易懂地回答。非常感谢您。
1. 获取浏览器发送的请求。
2. 将请求发送到网站。
3. 接收网站数据并将其发送回浏览器。
问题：
1. 当我使用Bootstrap.connect（主机，端口）时，如何将URL翻译成主机和端口？
2. 当我使用HttpServerResponseHandler.connect和ChannelHandlerContext.writeAndFlush（httpMessage）向网站发送数据时，如何获取来自网站的响应数据并将其发送回浏览器？
这是我学习Netty的第一天，请尽量简单易懂地回答。非常感谢您。
public class Server {
public static void main(String[] args) throws InterruptedException {
final int port = 8888;
// copy from https://github.com/netty/netty/wiki/User-guide-for-4.x
EventLoopGroup bossGroup = new NioEventLoopGroup();
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap b = new ServerBootstrap();
b.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
public void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast(new HttpRequestDecoder(), new HttpServerRequestHandler());
}
})
.option(ChannelOption.SO_BACKLOG, 128)
.childOption(ChannelOption.SO_KEEPALIVE, true);
// Bind and start to accept incoming connections.
ChannelFuture f = b.bind(port).sync();
// Wait until the server socket is closed.
// In this example, this does not happen, but you can do that to gracefully
// shut down your server.
f.channel().closeFuture().sync();
} finally {
workerGroup.shutdownGracefully();
bossGroup.shutdownGracefully();
}
}
}
public class HttpServerRequestHandler extends ChannelInboundHandlerAdapter {
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) {
// step 1 get data from browser
if (msg instanceof LastHttpContent) {
ctx.close();
return;
}
DefaultHttpRequest httpMessage = (DefaultHttpRequest) msg;
System.out.println("浏览器请求====================");
System.out.println(msg);
System.out.println();
doWork(ctx, httpMessage);
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
cause.printStackTrace();
ctx.close();
}
private void doWork(ChannelHandlerContext ctx, final DefaultHttpRequest msg) {
// step 2 send data to website
// translate url into host and port
String host = msg.uri();
int port = 80;
if (host.startsWith("https://")) {
host = host.replaceFirst("https://", "");
port = 443;
} else if (host.startsWith("http://")) {
host = host.replaceFirst("http://", "");
port = 80;
}
if (host.contains(":443")) {
host = host.replace(":443", "");
port = 443;
}
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
Bootstrap b = new Bootstrap();
b.group(workerGroup);
b.channel(NioSocketChannel.class);
//b.option(ChannelOption.AUTO_READ, true);
b.handler(new ChannelInitializer<SocketChannel>() {
@Override
public void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast(new HttpServerResponseHandler(msg), new HttpRequestEncoder());
}
});
// question 1
ChannelFuture f = b.connect(host, port).sync();
//ChannelFuture f = b.connect("www.baidu.com", 443).sync();
f.channel().closeFuture().sync();
} catch (Exception e) {
e.printStackTrace();
} finally {
workerGroup.shutdownGracefully();
}
}
}
public class HttpServerResponseHandler extends ChannelOutboundHandlerAdapter {
private Object httpMessage;
public HttpServerResponseHandler(Object o) {
this.httpMessage = o;
}
@Override
public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) {
System.out.println("网页请求结果=========================");
System.out.println(httpMessage);
System.out.println();
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) { // (4)
cause.printStackTrace();
ctx.close();
}
@Override
public void connect(ChannelHandlerContext ctx, SocketAddress remoteAddress,
SocketAddress localAddress, ChannelPromise promise) throws Exception {
System.out.println("connect !!!!!!!!!!!");
// question 2
ctx.writeAndFlush(httpMessage);
}
}