在前一篇中，實現了一個簡單的Http Server，這次來實現一個Http客戶端。
為了方便進行測試，這次把這個Http客戶端整合到SpringBoot裡邊，呼叫流程是：PostMan -> SpringBoot Controller -> Http客戶端 -> Http Server

簡單Http連線

每次請求：客戶端建立到服務端的連線，發請求，收相應，然後關閉連線。
SimpleNettyHttpClient:

@Slf4j
@Component
public class SimpleNettyHttpClient {

	private static final int _1M = 1024 * 1024;

	private EventLoopGroup workerGroup;

	@PostConstruct
	public void init() {
		workerGroup = new NioEventLoopGroup();
	}

	public String sendRequest(String url, String requestBody) throws Exception {
		Bootstrap boot = new Bootstrap();
		boot.group(workerGroup);
		boot.channel(NioSocketChannel.class);
		boot.remoteAddress("127.0.0.1", 8080);

		SynResponse<String> synResponse = new SynResponse<>();

		boot.handler(new ChannelInitializer<NioSocketChannel>() {

			@Override
			protected void initChannel(NioSocketChannel ch) throws Exception {
				ch.pipeline().addLast(new StringEncoder());
				ch.pipeline().addLast(new HttpClientCodec());
				ch.pipeline().addLast(new HttpObjectAggregator(_1M));
				ch.pipeline().addLast(new TestHandler(synResponse));
			}
		});

		ChannelFuture f = boot.connect().sync();
		log.info("已連線");

		URI uri = new URI(url);

		DefaultFullHttpRequest request = new DefaultFullHttpRequest(HttpVersion.HTTP_1_1, HttpMethod.GET,
				uri.toASCIIString(), Unpooled.wrappedBuffer(requestBody.getBytes("UTF-8")));
		request.headers().set(HttpHeaderNames.CONTENT_LENGTH, request.content().readableBytes());
		log.info("組裝Request");

		Channel channel = f.channel();
		channel.writeAndFlush(request);
		log.info("寫Request");

		channel.closeFuture().sync();
		log.info("關閉Channel");

		//workerGroup.shutdownGracefully();

		log.info("同步阻塞獲取Response Content");
		return synResponse.getResponseContent();
	}

	public static class TestHandler extends ChannelInboundHandlerAdapter {

		private SynResponse<String> synResponse;

		public TestHandler(SynResponse<String> synResponse) {
			this.synResponse = synResponse;
		}

		@Override
		public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {

			FullHttpResponse response = (FullHttpResponse) msg;
			String content = response.content().toString(CharsetUtil.UTF_8);
			log.info("收到服務端response：{}", content);

			synResponse.setResponseContent(content);
			log.info("Response content放入result");

		}
	}
}
 

Controller:

@Autowired
private SimpleNettyHttpClient simpleNettyClient;

@RequestMapping(value = "/postStringSimple", method = RequestMethod.POST)
	public String postStringSimple(@RequestBody String data) throws Exception {
		
		String res = simpleNettyClient.sendRequest("http://127.0.0.1:8080/test", data);
		logger.info("Controller返回：{}", res);
		return res;
	}